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WI-FI Final Report - Electrical and Computer Engineering

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1. Folder Filename File Format root Readme txt ASCII text file Documentation Final Document doc Microsoft Word Document Word 2000 Presentation ppt Microsoft PowerPoint HostiSockets TCPConnect sln Visual Studio Solution file Host DirectSound NetTalker sln Visual Studio Solution file Remote WaveForm API DialogApp vcw eMbedded Visual C 4 0 workspace file Remote Sockets TCPConnect vcw eMbedded Visual C 4 0 workspace file Remote DirectShow DialogApp vcw eMbedded Visual C 4 0 workspace file Remote DirectSound DialogApp vcw eMbedded Visual C 4 0 workspace file WavSamples White wav Generated White noise waveform audio WavSamples Pink wav Generated Pink noise waveform audio WavSamples Whitespkr wav PDA Speaker White noise waveform audio WavSamples Pinkspkr wav PDA Speaker Pink noise waveform audio WavSamples Whitemic wav PDA mic White noise waveform audio WavSamples Pinkmic wav PDA mic Pink noise waveform audio Each directory for host or remote contains the source and the environment setup files for each of the methods we had coded to find a solution The source for each project is handled by the project files listed in the table above For each platform the WaveForm APT folder holds the solution that we finally developed for presentation The WavSamples folder on the root contains audio samples that were recorded or generated for frequency response testing The Generated sounds were created using NCH tone generator available for
2. Function Input Occurs Output Description Start Playback none when user presses the Play button request for audio stream sent to host When the user presses the Play button on the SRU the playback filter graph is created and a play command is sent to the host to request an audio stream of the last recorded track Play Sound streamed audio from host when the host responds to with a host ready play audio to the built in speaker or headset When the host confirms it is ready the playback filter graph is run and the audio stream from the host begins The audio is played back through the SRU s built in speaker Change Track Forward none during playback when user presses the Track Forward button skip to file request sent to host When the user presses the Track Forward button while an audio stream is playing back a request is sent to the host to stop streaming of the current track and begin streaming of the next recorded track Change Track Back none during playback when user presses the Track Back button skip to file request sent to host When the user presses the Track Back button while an audio stream is playing back a request is sent to the host to stop streaming of the current track and begin streaming of the previously recorded track Function Stop Playback Input none Occurs during playback when user presses either the Play or Stop button Output end stream command sent to host Desc
3. Fig E 3 Creating a CLSID DSNetReceive variable and using it to allocate a filter into memory How does the host program find the CLSID for the filter so it can use it The answer is that it doesn t you hard code the value into your program after discovering it in the registry or in the filter DLL source The example above shows how a program stores the CLSID in a variable for use by CoCreatelnstance 2 2 5 Creating The Filter Graph and its Filters in Memory The filters we used in our DirectShow RRS include an Audio Network Receiver and an Audio Network Sender Both of these were derived from Microsoft sample code included in the Summer 2003 Update of the DirectX 9 SDK specifically the DSNetwork project They originally used multicasting see the Windows Sockets documentation but we modified them to send over a simpler peer to peer scenario Here is a step by step algorithm in order to do this 1 Build the DLL project or set the solution s build order such that the DLL is built and registered before your main application project compiles If this works it will send the appropriate CLSIDs into the registry 2 Declare your DLL s CLSIDs somewhere in your main program as was done in Figure E 3 3 Initialize COM and create an instance of the Filter Graph object itself 20 CoInitialize NULL CoCreateInstance CLSID FilterGraph NULL CLSCTX INPROC SERVER D IGraphBuilder void
4. Do Fig E 14 Connecting a socket to a remote computer We are making the telephone call on this end being implicitly bound to the local address Remember that connect also needs its port and address in network byte order 5B Listen to client Server Side The data transfer socket provided by accept SOCKET sock trans 0 sock val listen sock SOMAXCONN Check for errors OMITTED sock trans accept sock Socket to accept connections on NULL Pointer to contain client s address NULL Size of above F Check for errors OMITTED Fig E 15 Listen and accept and a new data socket The receiver code is always trickier than the sending code in network programming 1isten is analogous to plugging a phone into the telephone jack and accept is like picking up the phone when you hear the phone start ringing Notice that the accept function returns the value of a new socket which will be used to move data back 30 and forth as the original socket continues listening for other connections This behavior isn t terribly useful for a simple test program but it s how sockets work so you just need to know it Again you must set up the addresses you send these functions in a network byte order struct as done in step 4 An important fact to remember is that by default accept will block This means that the program will wait for incoming connections as long as it needs to or until a tim
5. EC COMPLETE evCode EC_USERABORT CleanUp break hr pMEvent gt GetEvent amp evCode amp paraml amp param2 0 return hr Fig E 10 Handling filter graph events For simple event handling like we did we didn t need to worry about the specifics of what the event parameters paraml and param2 were other than they needed to be freed after every GetEvent call 2 2 8 De allocating Objects After the graph is done running and you re done with all your DirectShow objects call the Release method on each one The filter connection algorithm shown in Fig E 6 demonstrates the PinList pointer being released every time it contained a new value Every time the filter graph needs to do a new playback or recording session it needs to be Re leased and recreated connected in this same manner Failure to Re lease all the objects you create will result in memory leaks and runtime errors after your DirectShow graph is done doing its job 2 2 9 Concluding Remarks About DirectShow The hardest parts about using DirectShow are setting up the filter graph correctly and verifying your event handler works It cannot be stressed enough that a programmer needs to do error checking on the return value of each and every DirectShow method call especially if they are just starting out Look at Fig E 5 or the RRS source code for examples of error checking If the program doesn t prop
6. 2000 00 2000 00 Total Cost 6074 00 We supplied our own personal computer to develop this project For a developer just starting out this would be an anticipated cost for a development computer Our sponsor requested that we use this handheld computer and they supplied it and covered the cost In theory this project could be developed on any handheld computer that is based on the same ARM architecture and that includes an audio device speaker and microphone E l WINDOWS DEVELOPMENT ENVIRONMENT DOCUMENTATION E 1 1 Introduction If you have never developed a Windows program before buckle up and take notes Windows development is a completely different experience from the Unix terminal editor compiler experience that lower level college programming courses at colleges such as the University of Idaho teach One must know object oriented programming quite well before they can use Microsoft s class based tools effectively This section describes application development for Windows XP and Windows CE NET using the Visual Studio NET and eMbedded C 4 0 development environments along with the entire Windows CE SDK and multiple versions of the DirectX SDK This is a very broad overview of the processes used to develop this software The technical notes section of the appendix contains how to information for using specific Visual Studio and eMbedded C functionality All the software we used was obtained either from the University of I
7. Construct Buffer DSBUFFERDESC dsbd DSCBUFFERDESC dscbd Description 6 Create Sound Device DirectSoundCreate DirectSoundCaptureCreate 7 Set Priority Level pDS8 gt SetCooperativeLevel 8 Create Buffer pDS8 gt CreateSoundBuffer pDSC gt CreateCaptureBuffer 9 Begin Capture pDSCB gt Start 10 Lock Buffer Section pDSB gt Lock pDSCB gt Lock 11 Copy Buffer Data memcopy function memcopy function 12 Unlock Buffer pDSB gt Unlock pDSCB gt Unlock 13 Begin Playback pDSB gt Play 14 Stop Buffer pDSB gt Stop pDSCB gt Stop Table E 5 Steps to create and use DirectSound buffers used only for capture or playback 38 1 Initialize the COM Library Call Colnitialize NULL before doing any DirectSound code in order to initialize COM Colnitialize returns an HRESULT which will indicate if the call completed successfully or failed 2 Construct Sound Device Call the constructor for the DirectSound or DirectSoundCapture device LPDIRECTSOUND pDS8 NULL LPDIRECTSOUNDCAPTURE pDSC NULL Fig E 27 Constructing a DirectSound object 3 Construct Buffer Call the constructor for the Secondary Buffer or Capture buffer PDIRECTSOUNDBUFFER pDSB NULL PDIRECTSOUNDCAPTUREBUFFER pDSCB NULL Fig E 28 Constructing a DirectSound Buffer object 4 Construct WaveFormat Structure The WAVEFORMATEX structure is used to specify the number of channels sampling rate and bit p
8. SETUP oe 4 USING THE SYSTEM ia 5 TROUBLESHOOTING da 5 B SPECIFICATIO Sacando nana ba Eras o So patas Baco JE Sc EI sass SUS DA CSN do cd sess eaacueceasessoacsaececsbacbswsueeeseetse 7 C ORGANIZATION OF CODE AND DOCUMENTS ON ACCOMPANYING CD oonoccccnnnnccnonnonconnnonccnnoncononos 8 D BILL OF MATERIALS sc csssssenio caccessinoencanoicacas tudes dado coc evsescasestednsveasecesscedeconbensescesceSencdeedcedsose sostectesvodcesecteceaseose 9 E 1 WINDOWS DEVELOPMENT ENVIRONMENT DOCUMENTATION cccccccssssscssscccssssssscsscceeees 10 E 1 1 EN TRODUC TION AEE E EEEE E A ae aa Miche doa Sok SG EEE a Sata a a 10 E 1 2 THE DIRECTX SOFTWARE DEVELOPMENT KIT SDK 0 ceeceesseessessceeeceeeeeecesecsecneceaecaeeeneeeaeenseeneeereeas 11 E 1 3 HOST DEVELOPMENT MICROSOFT VISUAL C NET cccccccccccccessssscesececsesessscescceceesesssaeeeeeceeeentsaeeeeees 12 E 1 4 REMOTE DEVELOPMENT MICROSOFT EMBEDDED C 4 0 ccccccsessscecececeesessscecccecseseseseceeeceesenssaeeeeees 14 E 1 5 WINDOWS CE PLATFORM BUILDER AND WINDOWS CE EMULATOR cccesessssssceeecececeensececeeeceesenssaeeeeecs 16 E 2 WINDOWS APL DOCUMENTATION cases sesesrisiaco dentases dias antena eras setvoccesesesosssaveededesesesctessosesesvecstcbessedes 17 E 21 INTRODUCTION AA amor oii ai T he ote tia coil 17 E 2 2 DIRECTSHOW a Sei eau ea e CIEE BC YG i a Bee hv EER 18 E 2 3 WINDOWS SOCKETS voii ri mentes dono adiestrado baba are a 27 E 2 4 AFX OBJECTS CSOCKET CCESOCKET CSOCKET
9. 3 Type a name for your project and click Next Then click Application Settings to define a few important properties for your project 4 Click Application Type Console Application and choose to Add Support for MFC 5 Under Additional Options uncheck the box for Precompiled Headers 6 Click Finish to close and start the project You are now ready to start inserting code that uses the MFC base In Closing The host application uses the Microsoft Foundation Classes to make functionality operate more smoothly and more efficiently under Windows environments Using MFC makes the host application work well with the other common objects used by Windows 59 Platform Builder Windows CE OS Images and Platform SDKs Justin Cassidy Revision 3 Introduction The Platform Builder is used to create a fine tuned version of Windows CE with exactly the hardware support and protocols your embedded device needs There are two important steps most developers need to take in order to test applications that use APIs such as DirectX 1 Create a Windows CE platform with the required DirectX libraries 2 Create a Software Development Kit SDK so you can use the OS image with the remote device through the eMbedded C IDE Our team needed to make an image with DirectX support as we were getting registry errors for classes not included on our default emulator image The platform builder can automatically bu
10. CSocket pointer variable 3 Create the Socket Call the Create member of the new CSocket object and specify the port nPort type of socket SOCK STREAM and IP address of the local computer s network adapter you wish to create the socket on The Create function returns a zero on failure if m pSocket gt Create nPort SOCK STREAM myAddress delete m_pSocket m pSocket NULL cout lt lt Socket Create Failed n return 0 Fig E 21 Creating the socket on the specified network adapter and port 4 Start Listening On the server application call the Listen member of the CSocket to listen for incoming socket connection requests on that port The Listen function takes one parameter which is the number of connection requests it is allowed to queue up Listen is a blocking function meaning program execution halts on that call until a connection request is received 5 Seek a Connection Once the server is listening for a connection the client can request a connection using the Connect member of the CSocket The Connect member takes two passing arguments the IP address of the server and the port on which the server is listening for a connection The Connect function returns a zero on failure if m pSocket gt Connect ServerAddress nPort delete m_pSocket m pSocket NULL cout lt lt Connect to server failed n return 0 Fig E 22 Connecting the Client socket to the Server 6 Construct new Socket Once
11. Effect Analysis 1 Potential Failure Modes Together we brainstormed what we thought were potential failure modes however likely or unlikely they might be The list is below see Table 3 List of Potential Failure Modes TABLE 4 LIST OF POTENTIAL FAILURE MODES 1 Unit out of network range or obstruction 2 Low battery life 3 Physical damage 4 Other systems down WAP 5 HD fullon host 6 Microphone malfunction 7 DirectShow or library failure 8 Host OS not working 9 DLL doesn t run at startup 10 No soundcard or network card detected 11 DirectX not installed 12 Other DirectX applications using resources libraries occupied 13 Memory leak or memory full 14 Tracks unavailable deleted or pointer corrupted 15 Host OS not working 2 Assign a Severity rating for each effect Here we decided on a number to scale how severe the specified event would be if it were to occur A higher number on an event means such an event occurring would have more severe or detrimental effects 3 Assign an Occurrence rating for each failure mode The following list outlines the occurrence rating we assigned to each failure mode based on how often the failure mode would be likely to occur In this case higher numbers mean that the event is more likely to occur 4 Assign a Detection rating for each failure mode Here we assigned a number to each failure mode to describe how easily a given failure mode would be to dete
12. SDK Static Libraries dsound lib Main DirectSound library Runtime Installed DirectX 8 0 or later not included on Symbol OS Image 2 5 1 Using DirectSound Buffers To use the DirectSound API you must first initialize the COM library Once this is done you can create the DirectSound device and use the device to create a DirectSound buffer in the format specified in a DirectSound Buffer Description structure Once the buffer is created you can then lock a portion of the buffer or the entire buffer and using a memcopy routine copy data into or out of the buffer Using a Playback buffer you must first memcopy the data into the buffer then Play the buffer With a Capture buffer you do the opposite and first Play the buffer to allow the sound device to capture audio into the buffer then lock the captured portion of the buffer and memcopy the data out of the buffer Once the memcopy is complete you Unlock the buffer which frees that part of the buffer back to the sound device Description Secondary Playback Buffer Capture Buffer 1 Initialize COM library CoInitialize CoInitialize Construct Sound PDIRECTSOUND pDS8 PDIRECTSOUNDCAPTURE pDSC Device 3 Construct Buffer PDIRECTSOUNDBUFFER pDSB PDIRECTSOUNDCAPTUREBUFFER pDSCB 4 Construct WAVEFORMATEX wfx WAVEFORMATEX wfx WaveFormat 5
13. addr yourlP server sin family AF_INET server sin port sPort server sin addr S un S addr ADDR ANY sockval bind sock my ip sizeof my ip Stores address in form for connect Stores address for explicit bind IP address and port htons 65074 send ip address 192 168 0 1 twork byte order INADDR NON GI Fig E 13 Address conversion to network byte order and binding to that address 29 Network byte order is the order in which the bits are sent over the network The functions and structures above are standard across most sockets implementations and they convert the input from whatever form provided to a big endian form which is either an unsigned long the IP address or an unsigned short the port number depending on how many bits are used to store the field in the IP header bind and other functions expect a structure containing the network byte order form of the local address and port it is using 5A Connect to server Client Side struct sockaddr in saddr usPort and ulIP have been converted to network byte order using htons and inet addr respectively OMITTED saddr sin family AF INET saddr sin port usPort saddr sin addr S un S addr ulIP Attempt to connect to the remote machine sock val connect sock LPSOCKADDR amp saddr sizeof saddr
14. amp pFGraph Fig E 4 Allocating space for a Graph Builder object in memory It will make life much easier if you either make the pointer to the graph memory either global or in a readily accessible class Do the same for all of the filters you create 4 Next create any filters you need using the same technique as in step 3 If your filters are not homemade look up the CLSID FilterName variable for that filter so you can call it with CoCreatelnstance Pay attention in the API documentation to what classes this filter derives from ie IBaseFilter or IFileSinkFilter the fourth argument of CoCreatelnstance This determines what methods are available to your filter and what methods are available to its pins 5 Now you ll need to set up each filter s special parameters Most filters have unique methods that need to be called in order to find the right audio hardware or to set the input or output file For the network filters you need to set their destination or source IP address These methods and parameters are described in the Microsoft DirectShow documentation under DirectShow Reference as well as in our source code 6 So you ve created the filter graph and the filters but there s one step left If you have created all your filters but have problems later this is a likely cause Remember to associate these filters in memory with the filter graph object by addi
15. and hear what the recognizer thought you just said so the pointer table would have been for the more musical user rather than the dictation user At this point the only operations that are correctly working are the recording of audio data and the playback of that same audio data The host is not yet automatic in that someone has to also sit at the host computer and tell it to start listening or sending Another shortcoming in our current system is that the operations have no graceful stop In order to switch from recording to playback the users of both ends must shut down the applications and restart them then change the modes they use by answering the prompts differently We have not yet tried to attach voice recognition to the host Our audio data is sampled such that the fidelity should be more than good enough to accommodate descent accurate voice recognition but we cannot say that is true with any certainty This part of the project then is entirely untested Il OPERATIONAL SPECIFICATION A Operational Overview The driver program and the wireless remote sound recording unit SRU work together to take audio recorded on the device and provide it to the host computer as a virtual microphone input Together they create a Remote Recording System RRS The RRS starts with the host driver running in the background on a host machine with a wireless network adapter and a SRU that is powered down The SRU is turned on and it per
16. b Select WEP encryption and provide an arbitrary key It will tell you how long your key can be Remember the key you used for this step as you ll need it when configuring the remote unit Our key was a ten character hex key i e characters in the set 0 f which made it a 40 bit WEP key c Make sure you check the option for ad hoc network 7 Usually neither computer on a peer to peer network knows how to self configure an IP address using DHCP So you ll need to set a static IP address a Right click your Wireless Ethernet Connection icon again select Properties and then find Internet Protocol TCP IP and click properties b In the next window tell it to use the address you specify We chose an address that wouldn t likely be on the other networks the host may be connected to namely 192 168 0 108 Remote 1 Double tap the network card icon on the Windows CE taskbar and select WLAN Profiles 2 Create a new profile and do the following a Give the profile the same name you gave your host profile Locus b Click the check box to set the connection to ad hoc mode c Click the encryption tab and provide the same key you did earlier If you did a 10 character key earlier as described select 40 bit Shared Key as the encryption algorithm d Click the IP Config tab and give yourself a static address Ours was 192 168 0 108 e Back at the WLAN Profiles window connect to the ne
17. back at the first track in the list Troubleshooting If you have problems with the system try to troubleshoot the problems with the following table Steps you take here will make it much easier to fix the system if you have to call Support for help Symptoms Possible Causes Solution Device will not record Dead Battery Charge the batteries according to the Quick Start Guide supplied with the remote Host has no free disk space Free some disk space on the host computer Host and Remote unable to communicate over network Ensure the host s wireless card is properly installed and configured and the remote and host are within range of each other Host s Remote Management Application not running Start the Remote Management Application and ensure it is in the Startup folder in Programs on the Start menu Remote is not configured to communicate with Host Use the Host s Remote Management Application to add your Remote to the list of known Remotes Remote unit software not installed properly Follow the directions in step ii 3 to install the remote software on the remote unit Device will not playback No tracks have been recorded Record a track to playback Dead Battery Charge the batteries according to the Quick Start Guide supplied with the remote Host and Remote unable to communicate over network Ensure the host s wireles
18. free download 6 The PDA spkr samples were the result of playing the generated sound over the PDA s spkr and the PDA mic samples were recorded on the PDA using the PDA s microphone D BILL OF MATERIALS This project required few materials for solution They are listed below along with a table that details the total costs of this project if the developer were to start from scratch and buy each component Gr pe Ooh Microsoft Visual Studio NET 2003 Microsoft Windows CE Platform Development Kit includes eMbedded Visual C 4 0 Microsoft eMbedded Visual C 4 0 SP3 Microsoft DirectX Software Developer s Kit Development computer PRmoe ae sp Windows XP Professional edition Pentium 4 or Athlon processor 256 MB RAM 3000 MB free hard disk space for Visual Studio NET 2003 and documentation 300 MB free hard disk space for Windows CE Platform Development Kit and service packs 100 MB free hard disk space for project files and builds 500 MB free hard disk space for DirectX SDK Wireless network card capable of transmitting over 802 11b Wi Fi standard Windows CE 4 2 NET based handheld computer For our project we used the Symbol PPT8846 handheld Description Qty Unit Cost Extended Price 1 Visual Studio 1 1 079 00 1 079 00 2 WinCE Platform Kit 1 995 00 995 00 3 eVC4 SP3 1 0 00 0 00 4 DirectX SDK 1 0 00 0 00 5 Development computer 1 2000 00 2000 00 6 Symbol PPT8846 1
19. from the drop down list Note that you can only host one remote at a time Using the System Dictation To use the dictation feature simply press the Rec button once on the unit When the Record indicator light stops flashing and stays on steady the system is ready to receive audio data and transmit it to the host computer for processing To stop recording press the stop button on the remote On the host computer you should be able to see the effects of your recording either in the voice recognition program or in the audio application you are using depending upon your situation By pressing record you started recording a new audio track and by pressing stop you signal the end of the track The number of tracks you can record and store at a time is controlled by the Host s Remote Management Application The default number of tracks is set to ten but this number can be changed easily by opening the settings in the Remote Management Application The only limit on the size of audio data that can be stored is the size of your free hard disk space Please note that the size of tracks you record increases with the amount of time stored in the track If your host computer is out of hard disk space to take dictation you may be unable to record new audio data or translate voice into text In this case you will need to clear some disk space Refer to your computer s help system for information on freeing some disk space Playback
20. is simply a dialog with buttons for playback recording and so on Console applications run within the Windows command prompt and resemble the Unix terminal applications of old They can use printf and scanf calls For those experienced with Unix programming as we were a console app was the simplest way to test the Windows APIs we were learning 1 3 3 Finding Variable Function Class Method Declarations Part of the power of Visual Studio is that developers are freed from their documentation and can rapidly find class and variable definitions The class list drop down and context menus help to navigate through objects and their methods rapidly Additionally by placing your cursor on any function or method name and pressing F12 you will be taken to where that variable or function is defined even if that definition is contained in a different file from the one you re viewing When you type in a class name followed by two colons both Visual Studio and eMbedded C will show a scrollable list of methods and variables for that class This auto completion list is very useful to help find variables that your program might need such as a window handle for sending the window s memory address to other functions Another handy tip is to switch between the IDE s child editor windows by pressing CTRL TAB or CTRL SHIFT TAB This can be used in most document style applications that handle more than one open document 1 3 4 Static and Dynamic Li
21. plug it into the cradle or cable firmly Windows will automatically find the handheld device and ask you to establish a Partnership with the device Here you can allow the device ability to connect to more than one host computer for synchronization or to sync with only one computer eliminating partnerships with other computers that are stored on the handheld device Once you have a partnership established you can connect to the remote device much like a disk drive that is attached to your computer 6 For Serial COM port cradles and cables a b c After Windows is finished loading open the Properties Page for My Computer Make sure you have administrative privileges On the Hardware tab click Device Manager In the hardware list that appears find the Ports section of the hardware category tree Make sure you are viewing the devices by type not by connection Double click the COM port that your cradle or cable is attached to open the properties for that port Usually this is COM1 or COM2 but your specific setup may vary Now click the button for Advanced settings In the dialog that appears make sure the box is unchecked for Use FIFO buffers Restart your computer After Windows is finished reloading turn on the handheld device and connect it to the cradle or cable firmly Click Start All Programs ActiveSync Windows should automatically find your devi
22. string make sure they are set up correctly For test programs I find it easier to make static arrays of the form const char than to use dynamic buffers but your mileage may vary 7 Monitor the Socket State The select function is confusing but it serves an important purpose it will tell you the state of your socket Say the client has been sending data for a little while and decides to close the socket on its side The server will 31 continue listening and accepting data on this connection oblivious to the fact that the client has closed its side of the socket There s probably no reason to keep this socket open once either side has closed So what you do is call select to figure out the state of the socket after every send or recv and if either side has closed down you ll do the same sock val select sock val select NULL amp sockets NULL NULL NULL NULL NULL amp sockets NULL NULL The first select function is checking a list of sockets to see if they are readable while the other list is checking to see if the sockets are writeable Look up the FD_SET and FD_ZERO to see how to modify this special sockets list 8 Disconnect Close the Socket sock val shutdown sock SD RECEIVE sock val shutdown sock SD SEND sock val closesocket sock Fig E 18 Shutdown procedure for closing the sock socket 9 Shutdown the Runtime Library Just call WSACleanup with
23. the data rate This comes out to 187 milliseconds Theoretically in order for the system to keep up with itself and remain in Real time operation the total latency due to network must me less than the latency due to audio buffering it must take less time to send data over the network than it does to record it or play it back By this calculation our theoretical system latency is at most 374 milliseconds which is 25 off the measured value We believe this discrepancy may come from other processes running on either end of the system since Windows is made for multitasking but we have not verified that idea This delay may also come from the fact that the version of code we were running on both ends were the debug versions of the build so they had the debugging symbols and extra information that makes the program run inefficiently To verify that the handheld unit would meet our audio specifications we ran a few speaker and microphone frequency response tests For an accurate test Mr Stear generated a sample of pink noise the inverse of all frequencies and a sample of white noise all frequencies To perform the speaker test the noise samples were recorded from the handheld unit s speaker using a highly sensitive microphone The microphone test used a similar technique Using the speakers on the development computer as the source the white and pink noise samples were recorded on the handheld unit s microphone Then using a
24. the server has received a connect request a new socket needs to be constructed to accept the incoming request on This way the server always has one socket used for listening for new connection requests and always creates a new socket to connect to any socket connection requests 35 7 Accept Connection Using the newly created socket that has not yet been initialized or connected the server calls the Accept member of the original listening CSocket and passes the newly created socket as it s only parameter Accept then connects the newly created socket to the Client socket that requested the connection The Accept function returns a zero on failure if m pSocket gt Accept m pConnectedSocket delete m_pSocket m pSocket NULL cout lt lt Server Accept Failed n return 0 Fig E 23 Accepting an incoming client connection request 8 Construct File Object Once a CSockets connection is established a new CSocketFile object needs to be created and attached to the connected CSocket The CSocketFile object acts as both a buffer for storing sent and received data and as a standardized File type interface so that reading and writing data to the CSocket connection is as simple as reading and writing data to a file You can construct the CSocketFile directly or create a pointer and call the new command to construct the object CSocketFile m pFile NULL m pFile new CSocketFile m pConnectedSocket Fig E 24 Cons
25. understand how to create network programs that use sockets after following the steps presented in this short overview of Winsock programming Headers Static and Dynamic Libraries Windows XP Headers winsock2 h Main Winsock 2 header ws2tcpip h TCP IP specific definitions and prototypes Static Libraries Ws2_32 1ib Main static library for Winsock version 2 Runtime Part of Windows XP Headers Static and Dynamic Libraries Windows CE NET 4 1 and 4 2 Headers winsock h Main Winsock 1 1 header Static Libraries winsock lil Winsock 1 1 static library Runtime Part of Windows CE 2 3 1 Using Connection State TCP IP Sockets TCP IP sockets work much like a telephone call one socket attempts to connect to a remote machine hopefully the remote machine answers and then data can be moved back and forth in full duplex fashion If the remote machine does answer the connection state guarantees reliable data transmission unless a hardware catastrophe occurs The following steps demonstrate what needs to be done for two sockets to talk to each other over TCP IP 27 To a beginner many of the socket functions are named confusingly It is just best to know when they need to be called rather than understand precisely what their purpose is in order to create simple programs Here s the recipe after this we ll dive into more detail If the steps for the client and server diverge we ll describe these differences in c
26. value to plug into the Error 28 3 Set Socket Options SO REUSEADDR char t T sock val RUE setsockopt Fig E 12 Setting socket options sock SOL SOCKET SO REUSEADDR char amp t sizeof t r The only socket option we care about is the one that lets us create multiple connecting sockets on the same port with the same source address By default calls to the bind or connect functions will fail if there is another socket on this port with a connection already 4 Bind Addres s to Socket Binding is a strange thing Some functions such as connect which we ll use on the client side later just automatically provide the socket with the client s own address This is called implicit binding For the server we need to bind the socket to the server s own address explicitly This involves a conversion step for putting the IP address and port number into network byte order struct soc struct soc Set up unsigned s const char Transla te these the Listener hort usPort nto net kaddr in client kaddr in server i unsigned long myIP INADDR ANY unsigned long yourIP inet _addr send ip address if myIP INADDR NONE yourlP shutdown sock SD RECEIVE shutdown sock SD SEND return 1 client sin family AF INET client sin port usPort client sin addr S un S
27. very important and should be done before recording begins with waveInStart However buffer allocation is a detailed process that is related more to the next step in our algorithm so it is omitted here HWAVE N hwin Stores the identifier of the open wave device after a call to wavel InOpen 43 RetVal wavelnOpen amp hwin Will point to open wave device WAVE MAPPER Device identifier amp wfx Format request NULL Callback function for event handling NULL No instance data CALLBACK NULL Flags E3 Allocate buffers to the sound device NOT SHOWN Start recording RetVal wavelnStart hwin Fig E 40 Opening the sound device for recording 4 5 and 6 Allocating Preparing and Unpreparing Buffers The Buffer Loop This is by far the most important part of the audio I O process These buffers are where the audio data is stored as it is transported from memory to the audio device Loops that read buffers from the audio device for recording follow the same process as loops that write buffers to the audio device for playback Don t worry about what preparing and unpreparing buffers means Just know that these steps must be done every time a buffer is to be used by the audio I O device The following code snippet creates two buffers that wave data can be put into Here s a quick rundown of th
28. 2 gt 0 m pArchive0ut Write pvAudioPtr2 dwAudioBytes2 Fig E 36 Sending captured audio data out on a connected socket 12 Unlock Buffer After copying the buffer data the locked portion of the buffer needs to be given back to the sound device This is done using the Unlock member of the DirectSound Buffer Unlock takes four parameters which should be the same two pointers and integers that the Lock command returned so that the exact same portion of buffer is unlocked as was previously locked hr pDSB gt Unlock pvAudioPtr1 dwAudioBytesl pvAudioPtr2 dwAudioBytes2 Fig E 37 Unlocking the locked portion of buffer 13 Begin Playback Because the playback buffer starts out empty it should not be played until sufficient audio data has first been written into the buffer Once enough audio data has been written to the playback buffer begin audio playback using the Play member of the DirectSound Buffer The Play member takes three parameters The first is reserved and should always be NULL the second is the priority of the sound playback must be zero unless the DSBCAPS LOCDEFER flag was set in the buffer description and a control flag hr pDSB gt Play 0 0 DSBPLAY LOOPING Fig E 38 Playing the playback buffer 14 Stop Buffer The Playback and Capture buffers can be stopped at any time using the Stop member of the buffer 41 E 2 6 Microsoft Waveform API Microsoft s Waveform API is the lowest lev
29. Algorithm for Manually Connecting Filters In order to get the correct pins from a filter you have to enumerate them all and do a quick search for the proper pin by checking the pin s direction as shown in the while loop above Input pins are always the first pins in the enumerated list so for the Infinite Tee we just chose the first pin using the Next method After we connect the actual pins on the filter they will remain connected even after we release the InPin and Out Pin variables we were using One line that might confuse you is the Reset method used by the PinList list This resets the list pointer to the head of the list just incase somehow PinList wasn t released properly and is just a safety measure 22 The Connect method won t work if you re trying to connect a filter that hasn t been added to the filter graph so you might want to check for errors with that hr value in your code Remember to call AddFilters to add the created filters to the graph in your allocation routines This process of connecting the filters is called manual connection DirectShow has many methods for automatically connecting filters together when it s working with simpler tasks like pull mode audio compression or local playback operations However these could not be used for our project because of our desire to use both push mode and pull mode filters Look at the RenderF i le method which creates a playback graph specifically tailored for its file argu
30. ECE Senior Design Project Final Documentation for Remote Recording System 6 May 2004 Sponsor Leighton R Wall Advanced Input Devices Team Dialect Justin M Cassidy lan D Olson Thomas R Stear cass0664 uidaho edu olso4398 uidaho edu stea7935 uidaho edu Instructor Dr Richard Wall Project Advisor Dr Richard Wall I INTRODUCTION ess rerrererenerereneorerarenesacennecereneseerasonasae sense sense censores atoa arara cenas casas es acena sc sans avant snasas 1 As BACKGROUND Ecce stereo errar a id il db data od a DAR iE 1 Bo INTENDED UG SE A A EE E E EE EE Re 1 C PROBLEM SOLUTION A te 1 D FUNCTIONAL AND NON FUNCTIONAL PARTS OF THE PROJECT oooooconcnccononononanonocncnnnnanonononnononnanononconononnanononcnnos 1 TL OPERATIONAL SPECIFICATION vcssssiscesseseneteosvenscvessenesvessdecsvsesasessscsecessevsesssusctsestevevesebuccdevecnecsssecnssvexsesesee 2 A OPERATIONAL OVERVIEW scssssccccccecsssseececececsessnsecesccecsesseaececececsensaseeeeececeessaeaeeecccsesenseaeeececsesesaaeeeeeesesensaaeas 2 B OPERATIONAL METAPHOR ecccccesssssssececececeeecsececececeessaueseecceceeauececececseaaeeeeeescseneaaeseeececseseaaaeeeeeceesensaaeeeeess 2 HI FUNCTIONAL SPECIFICATION sivecsecccssts cacseccocsssdeetcecesecodsascese idas de ca So se Una da do asa Go cocdvceseuacascaees desista o ascos 3 As BUNCIIONAL OVERVIEW d5csacoccences scsudedue col ii 3 Ba BUNCTIONAL METAPHOR oi dias 3 G EUNCIT
31. ET 4 2 Development Kit Microsoft Host Operating 31 December 2006 Windows XP System Microsoft Remote 30 June 2007 eMbedded Development C Environment Platform Builds WinCE 30 June 2007 Builder OS Images Intel Xscale Remote Hardware Estimated 2 3 years Architecture platform B Failure Rate Calculations The following scores are the product of using the Relex program to compute hardware reliability scores The use of Relex is outlined in the appendix section titled Using Relex to Calculate Hardware Reliability Scores Since we used a demonstration version of the program there is a limit to the number of parts that could be added into a system As a result the host computer system is built of three separate systems the power supply the mainboard CPU RAM I O controllers and chipsets and the overall PC with video sound modem and network cards as well as input devices and a display In a tree view the PC system is a root and the power supply and mainboard subsystems are the leaves The table below outlines the device tested the Failure Rate of the device in failures per million hours and the Mean Time Between Failure in hours see Table 2 Reliability Scores for Hardware Systems TABLE 3 RELIABILITY SCORES FOR HARDWARE SYSTEMS Part Failure Rate MTBF hours Host Computer 56 367 17 741 Power Supply 20 992 47 637 Mainboard CPU 14 738 67 851 Handheld Unit 0 109 9 096 360 C Failure Modes and
32. FILE AND CARCHIVE ocococcccconononononcnnnnnananononcnnoninnnnonoss 34 E 2 5 DIRECISOUND BUFRERS n a inca es du a veboedensetecucessoeahab ve oulcabe E a a Gde cado SENTA Odes ciones 38 E 2 6 MICROSOFT WAVEFORM API annn a citas salen ii E a E cidcid 42 E 2 7 BENEFITS AND DISADVANTAGES OF WINDOWS PROGRAMMING ccccecessessscecececsesesseseceeeceenesssaeeeeececeentaaees 49 F TECHNICAL NOTES SHEETS wiisssccsssseescsiasessessvsecesssesesacedesesscsdacessessssedsescecssaseesssenstedssvesdesteesoscasesedeseveostuseeec 50 G REFERENCES nereti ce sascccctiicess coto acid asi foda de de coeo Dra ea aa ida Us at ada ai ds cdas Nvidia dci S a 64 Remote Recording System using Wireless Networking in Windows platforms May 2004 Justin M Cassidy lan D Olson and Thomas R Stear Abstract This paper describes in detail the process we undertook to develop a system centering around a handheld unit capable of transmitting voice and audio data over a wireless network to a host computer for further processing including but not limited to voice recognition Among the named processes are a few technologies that could not be made to function by us They are included merely as reference Index Terms Wireless Networking Wi Fi Windows CE DirectX Waveform API Windows sockets I INTRODUCTION A Background he Wi Fi enabled Remote Recording System was designed to transmit audio data over Wi Fi networks between a handheld Windows CE device a
33. Fast Fourier Transform program the resulting waveforms were analyzed on a third octave scale to determine the range of active frequencies Those frequencies that fell outside a 10 dB drop were ignored The resulting frequency responses are given in the table below see Table 1 Handheld Speaker and Microphone Frequency Response TABLE 1 HANDHELD SPEAKER AND MICROPHONE FREQUENCY RESPONSE Pink Noise White Noise V f 1 f V f PDA Speaker 20Hz 16KHz 25Hz 16KHz PDA Microphone 16Hz 16KHz 16Hz 16KHz 3 7 Instruction Manual Our instruction manual will be based off our operational specifications and any usability guidelines documented in our technical notes sheets The instruction manual will consist of two main sections one for setting up the device on a wireless network and one for using the SRU and host software to record play and manage audio The wireless network section will be written specifically for a trained IT professional as this may be too complicated for easy installation by a doctor especially for setting up the device for use over an entire WAN It will describe how to set up the wireless communications between either a host and SRU or a WAN and a SRU The usage manual will detail how to play record change tracks and use the host on a level understandable to someone who has never used a modern stereo Additionally we will write a section to prime users of previous USB units on the new SRU host com
34. IGraphBuilder void amp m pGB if FAILED hr im pGB return E NOINTERFACE return NOERROR Figure 1 Calling the Graph Builder We re trying to create a filter graph with the graph builder allocating memory m PGB and checking to see if the operation worked If it did m_PGB will point to a non zero memory address and hr will be greater than zero thus making the condition fail 55 Instantiating the Filter Graph Whether doing audio playback or capture when using DirectShow the first step is to initiate the GraphBuilder The sample code in Figure 1 was copied from the DirectShow audio sample program When put into a method it was found that hr was failing and the pointer m pGB was NULL The CoCreateInstance was failing in Figure 1 After putting the error code contained in the hr value into Tools gt Error Lookup I learned I was getting a Class not registered error What does this mean REGDB E CLASSNOTREG A specified class is not registered in the registration database Also can indicate that the type of server you requested in the CLSCTX enumeration is not registered or the values for the server types in the registry are corrupt Figure 2 Microsoft Help Description ofthe CoCreateInstance Registry error I presumed this meant the default emulator image doesn t have all the DirectX libraries installed correctly So we created a new one a long and painful process See the Platform Builder te
35. ONS Geen ee des EERE EE EEEE aaa 4 IV MANUEACTURING T E AEE E N 6 A PRODUCT LIFECYCLE PLAN oeseoeoseeoreesseeseesereserseressrosseeoteettetttestts stts otto steo tetere speet te stts stts oreore recae oe eeens eese 6 B FAMURERATECALCULATIONS tds 9 C FAILURE MODES AND EFFECT ANALYSIS c cccccssccsscssccssecsccsssessecssesssesscesscesscsascsascssecseecaescsssesseesseeseess 10 Vi SOCIAL IMPACT A AE votan also vo ones TU atas bU Co SONDA O st TAIE qua suveuea sasaas asvevessisesees 10 A HEALTH AND SAFETY ISSUES aeee eae ne era a aerea nara t aaa narrar Sess r cancion 10 B ENVIRONMENTAL ISSUES ct sguestn est nDa tico dec pow o idad 11 VI SPECIFICATIONS NOT YET MET sricssscdecesssasecitssedcdsestveivsesedecsusssasusccsd scusssdbavosdedasedsesseitsssdeetsstedeaessse 11 VII FUTURE MODIFICATIONS Ss codtissssaoeadocise tarto Leco deco destas inseccdecesocssasvscedsoedesdhcesesssedesuscatsecsevedecusostcabe ss 11 No O eS IEEE ES NI A RS A OS AI 11 Bo REMOTE rta do Is os do ted dote dos ee Id dd es do recto Nal A A ON 11 VIII APPENDICES 00 cocci cstscaccnsctessascsesete cocsscocccunscaseasoonesaceeess sosseovecasvouse cossoosstecsesbesossbecscdecsesousdsocsacveseceveseaseese 2 AS USERS MANUAL sccdecssccttseccdssesoodsededsisecdeasessseessaseveseseesddessecesdeusecess seceaessenee no d dado pisa ads GU bb cade seesteosassdeesseceseonsecess 3 INTRODUCTION coi dais 3 ABOUT THIS GUIDE la eecoica 3 INSTALLATION Toda 3 INITIAL
36. S or simply bugs in the release software that were not found during testing Product updates will also be a key part of the product maintenance Any new technology or functionality added the Windows CE platform in the future that would be beneficial to the product can be integrated into the RRS Some key technologies that may be integrated in the future would be newer wireless networking standards that allow for higher fidelity or longer operating range of the system newer compression algorithms better suited to the system or speech to text conversion directly on the remote unit 6 End of Life The end of life conditions for the Remote Recording System will occur when maintenance of the software becomes expensive or impossible The main component of this RRS project is the software which can be reused on other architectures with Windows and network support Also writing for DirectShow dictates that we are writing for general audio and network functions rather than specific sound or network hardware This makes figuring out when this projects lifecycle will end difficult to say The table in the next column gives estimates of end of support for the key technologies in our project solution see Table 1 End of Life Estimates for Hardware and Software Technologies 6 1 Hardware From a hardware perspective on the original PPT 8846 XScale architecture a life cycle can be guessed based on how long previous generations of technology have
37. SoundCreate and DirectSoundCaptureCreate system calls take a newly created DirectSound Device object as a parameter and return it as a configured and ready to use object hr DirectSoundCreate NULL amp pDS8 NULL hr DirectSoundCaptureCreate NULL amp pDSC NULL Fig E 31 DirectSound Create system call 7 Set Priority Level When using a DirectSound Playback buffer the application must first call the SetCooprerativeLevel member of the DirectSound device This function takes the handle to the current window and a DirectSound defined flag to set the priority level of the application s sound playback The most commonly used priority level is DSSCL PRIORITY which allows the application to playback sound whether the window is active or inactive but also does not give the highest priority control over the sound device hr pDS8 gt SetCooperativeLevel hWnd DSSCL PRIORITY Fig E 32 Setting the sound playback priority level 8 Create Buffer Now that the sound device has been created and set up the DirectSound Buffer now needs to be configured to use that sound device This is done by passing the buffer and buffer description to the CreateSoundBuffer member of the DirectSound device hr pDS8 gt CreateSoundBuffer amp dsbd ppDSB NULL hr pDSC gt CreateCaptureBuffer amp dscbd ppDSCB NULL Fig E 33 Creating and configuring the DirectSound Buffer 9 Begin Capture When using a DirectSou
38. T terminology a project is a vcproj file containing a group of headers and source code files that creates a single static library DLL or executable A solution is a sln file that contains multiple projects A solution and its component projects can be copied together between computers To do so you must copy all files referenced by the solution and keep all the relative pathnames between the solution the project and the source files intact Solutions are used because often times a project requires a library to be built by another project before it can compile In this case you have a list of dependencies between your projects Not only can developers specify which projects depend on one another but they can also change the build order Both these options are available when you right click the solution name on the class or file view in the IDE 13 2 Project Wizards and Windows GUI Projects Like with Microsoft Office in Visual Studio a wizard is a way to create an empty Windows interface that your program can be built off of There are as many types of application wizards as there are Windows user interface libraries but the three primary types are document dialog and console Document applications have a menu bar at the top and usually a user either creates or modifies files within the interface They often call smaller dialog windows to set options these dialogs can be full featured applications in themselves The RRS remote application
39. To playback what you recorded simply press the Play button once on the remote You should hear the audio you just recorded play back over the speaker on the remote unit In the case of a voice recognition program you should hear the voice recognition program reading back the text you spoke into the remote If you have not yet recorded audio with the remote unit you will not be able to playback any audio This is also the case if you restarted your computer or closed the audio or voice recognition program you were using to record audio data The playback feature always plays back the last track you recorded unless you have used the track skipping buttons to navigate among tracks you recorded Note that if you record another track after skipping among the tracks the playback feature will again play back the last track you recorded Skipping Tracks To skip between tracks you have recorded press the Next or Prev buttons on the remote unit Each press will skip one track in the specified direction If you have not recorded any tracks then the skip buttons will not have any effect on the system The track skipping buttons work in a circular fashion For example if you recorded five tracks of audio data and you try to skip backward past the first track in the list you will effectively return to the top of the list and hear track five again If you try to skip forward beyond the number of tracks you have recorded you will arrive
40. When the record button is pressed once the SRU will verify the host is ready to receive audio The activity LED will turn on signaling the user to begin talking into the SRU Either the record or stop buttons can be pressed to finish the record operation As the sound is recorded it is streamed into the host driver as a virtual sound card input and simultaneously saved as an audio file for playback by host programs or later by the SRU Ten of these recorded audio sessions will be stored as files numbered from 0 to 9 most recent to least recently recorded For every hardware address name pair the host driver is configured for ten audio sessions will be stored 4 Playing Sound The SRU has an internal speaker used for playing back audio When the play button is pressed once the SRU will verify the host is ready to send the previously recorded audio session The activity LED will tum on signaling the audio has begun playing on the SRU Either the play or stop buttons can be pressed to finish the play operation The previous next track buttons cycle through the recorded sessions on the host session selecting a different session to be streamed back to the SRU for playback Pressing these buttons initiates the playback operations for this audio session Either the play or stop buttons can be pressed to finish this play operation SRU Interface The built in speaker is on the back of the unit and the microphone is on the top RRS Remo
41. are the first buffer to receive audio RetVal wav InPrepareHeader hwin amp first buffer sizeof WAVEHDR y Add buffer RetVal wav to the sound device nAddBuf fer hwin amp first buffer sizeof WAVEHDR RetVal wav InPrepareHeader hwin amp second buffer sizeof WAVEHDR Do RetVal wav nAddBuf fer hwin amp second buffer sizeof WAVEHDR Do Call waveInStart HERE Omitted int cnt nLoops ent 0 nLoops DESIRED TIME SECS 3 PRAIA ARS PE LEE The buffer loop while cnt lt nLoops EL Fd Device handle WAVEHDR structure Size of the buffer structure Device handle WAVEHDR structure Size of the buffer Device handle WAVEHDR structure Size of the buffer Device handle WAVEHDR structure Size of the buffer structure structure structure Capture a few seconds of audio Poll to see when the first buffer is done being written to while first_buffer dwFlags WHDR_ wavelnUnprepareHeader hwin amp first buffer sizeof WAVI Call MFC method right HERE omitted Prepare R DONE TRUE EHDR to write first buffer to a file or socket the first buffer while the second one is filling up RetVal wavelnPrepareHeader
42. ber of inputs depending on what hardware functionality the device driver supports If a filter doesn t have enough outputs it is connected to an Infinite Tee filter which converts a single output for a filter into any number of equivalent output pins DirectShow pins are either output pin objects or input pin objects and they all have a MEDIA TYPE a MEDIA SUBTYPE and a MEDIA FORMAT variable When filters connect to each other the combination of TYPE SUBTYPE and FORMAT must be compatible between the output pin and the input pin Alternatively if the graph builder finds proper intermediary filters to add that will convert the output pin to agree with the input pin s type it will add those in transparently For local file operations auto connection usually makes filter graph creation extremely easy Unfortunately the same cannot be said of streaming operations such as those needed for the RRS 2 2 2 c Data Flow in a Filter Graph The final point to note about DirectShow pins is that they are either synchronous deriving from the IMemInput class or asynchronous deriving from TAsyncInput Most of the Microsoft documentation refers to these as push mode and pull mode respectively The difference between the two is that in pull mode the filter graph s progress is determined by the downstream sink filter as it is the one that sends messages back up the graph to the upstream source to send data In push
43. bination 4 Release Plans The release of our product will be a package that includes a PDA with remote software preinstalled a disk with host software remote image and remote image installation program and a set of documentation either on disk or in paper format For use in hospitals the IT department will likely perform the installation and address management setup In the case of a private consumer the 8 user will likely be the installer so the documentation needs to be thorough enough to direct a person without formal computer training Our system is not overly complicated so the initial setup should be rather easy for any skill level To invite feedback on the new system we could setup an email address or phone number to collect opinions and feedback from users of the system Using the feedback we can develop upgrades or patches to improve and expand the operation of the system 5 Maintenance Once the Remote Recording System is released for distribution the maintenance process will begin As with any commercial software product a large part of the maintenance process will be fixing any software bugs that were not found before product release These bugs could arise from compatibility issues with certain host systems and OS versions that were not tested incompatibility with other software that may be running simultaneously on some host systems host OS updates that break compatibility with some features used in the RR
44. braries with Windows XP Windows programs often work with both lib format static libraries and dll format runtime or dynamically linked libraries DLLs When building a DLL project it will build a DLL and an exports lib file The idea without going into extreme detail is that without the lib file the application won t know what the DLL file contains Some programs solely use static libraries and build the final application with those but 12 this results in very large executables DLLs also have the handy property of being reusable by more than one program When working with Application Programming Interfaces such as Windows Sockets or DirectShow you need to go to your Linker Input settings and add the required lib files as per the API documentation For instance when building sockets applications for XP you need to add ws2 32 lib to the list of input libraries to include in addition to including the winsock2 h header file in your source code If your solution builds an application that relies on a DLL that is also built by your solution the application needs the output lib file made by the DLL project in addition to having the created DLL registered by the system DLLs are registered using the regsvr32 utility included with Windows XP In the Project Settings for a project there is an option under Linker settings that will register your DLL automatically after it is successfully built Finally before you start playing
45. cancode Enter Enter Fl Tab F2 Left Cursor F3 Right Cursor F4 Escape Working with a Windows button named amp Play the PDA Enter key could be assigned to keyboard scancode P but these keystroke values are reset every time the PDA does a hard reset So reassigning PDA keys in CE isn t recommended Because Windows buttons have a tab order by default the two PDA buttons F1 and Enter could be used to cycle between all the functionality of the dialogue box However we want each button to have a function Since we wish to interrupt stopping and starting audio with these keys our program will have to worry about event handling Our technical notes on event handling are discussed in the DirectShow section of our final report Debugging Overview I have not found a way to use printf or scanf or redirect stdin and stdout to a terminal within the eMbedded C IDE Not for lack of trying I can t find any documentation on how the little output window at the bottom of the IDE works although it does work with a vcl file HTML formatted in the project top level directory for its build log I tried redirecting output to that file but it doesn t work 53 Breakpoints are useful for seeing where you are in the code and assert statements in the debugger can look at variable values as the program is running This is the same sort of functionality debugging printf statements provide although there is no analogue for
46. ce and ask you to establish a partnership between the host 57 computer and the handheld device Here you can allow the device ability to connect to more than one host computer for synchronization or to sync with only one computer eliminating partnerships with other computers that are stored on the handheld device h Once you have a partnership established you can connect to the remote device much like a disk drive that is attached to your computer In Closing While the hard connection is not necessary for everyday use of the remote unit it will allow for testing and software repairs or updates later 58 Creating a MFC Console Application Project Tommy Stear and Justin Cassidy Revision 1 Introduction This paper describes how to setup and start a new project in Visual Studio that uses the Microsoft Foundation Classes What it is The Host Application uses the Microsoft Foundation Classes MFC to set the basis for certain Windows specific types and other global objects The MFC establishes objects global constants and type definitions that programmers can use to make applications operate more efficiently under Windows environments This includes useful wrappers to Windows Sockets network connections and writing files 1 Open Microsoft Visual Studio NET 2003 2 Start a New Project from the File menu Navigate through Visual C to the Win32 category and choose the Win32 Console Application
47. ch architecture Windows CE runs on including an emulator platform that runs on the host machine That said most of the function keys for debugging and searching F5 F10 etc are the same 1 41 Projects and Workspaces Visual C NET projects are incompatible with eMbedded C projects and vice versa Developers porting to Windows CE must create a new eMbedded C project and add all the files from the C NET project by hand Projects in eMbedded C follow the same rules and have the same properties as those in C NET Workspaces serve much the same function as solutions do in C NET grouping projects together handling dependencies and building projects in developer defined orders 1 42 Platforms For all versions of the Windows CE SDK installed PPT 88xx custom STANDARD SDK to name a few there will appear a platform profile In addition each profile will let the developer build programs for a specific hardware architecture such as the ARMVI MIPS or WinCE Emulator Finally the developer can choose to send this code to any target Windows CE devices attached to the development machine Usually this is just a single PDA device and the Emulator If the target is incompatible with the profile and architecture combination a warning message typically appears Some combinations will allow the program to be sent but then any attempt to run the program will fail because the binary format is incorrect for that architecture 143 Configuri
48. chnical notes on how to do this Hopefully Helpful Notes m_pGB and other filter graph pointer variables are protected in DialogappDl1g h so they can t be called unless the function is a method in the DialogappDlg class So don t use HRESULT Record but rather HRESULT DialogappDlg Record 56 Making ActiveSync Work Tommy Stear Revision 1 Introduction This paper tells how to install Microsoft ActiveSync file and database synchronization software on the host computer and to configure the host computer to connect with the remote unit What is it ActiveSync is a tool made by Microsoft that allows owners of handheld computing devices that are based on the Embedded Windows platforms to synchronize files with a desktop computer system running Windows With this tool users can synchronize their email and calendar databases to do lists and phone and address books and make them mobile on the handheld device The remote unit in the Remote Recording System is a device based on the Windows CE embedded computing platform 1 Download the latest version of ActiveSync from the Microsoft website in the Downloads area http download microsoft com 2 3 4 5 a b c Install ActiveSync on the host computer Install the cradle or cable supplied with the remote unit on the host computer Restart the host computer For USB cradles and cables After Windows is finished loading turn on the handheld device and
49. ct or how obvious it would be that that event occurred The higher the number the more detectable the failure mode 5 Calculate the Risk Priority Number for each effect In the table below Table 4 FMEA Table of Ratings we calculated the initial Risk Priority Numbers The RPN in the right hand column gives a scale for judging which risks are the highest priority meaning that they are the most severe most likely to occur and most detectable failure modes we brainstormed for the system The failure modes with the highest RPN values are the most important failure modes and need to be addressed with some form of safeguarding or even eliminated 6 Prioritize Failure modes for action Our top three failure modes are microphone malfunction low battery life and network devices out of range Obviously we can do nothing to safeguard the operating system without building a custom version of the operating system and fixing the bugs we might encounter so there is nothing we can do to reduce or eliminate the risk of the Host Operating System failing Also there is little that can be done to reduce or eliminate the risk of physical damage to the remote device The remote unit that we have been using for the development of this project is made to be very rugged so it will likely withstand a short fall once in a while An action we could take to help make the device more rugged would be to make or purchase a padded case for carrying the re
50. daho CS department for educational use or from the Internet Commercial and educational licenses are available for Visual Studio NET eMbedded C is a free download from the Microsoft Windows Embedded web site source DirectX SDKs are available from Microsoft s DirectX web site for free as well source The Windows CE SDK can either be obtained from Microsoft or a custom version can be created using their Platform Builder tool Vendors often supply their own versions of the Windows CE SDK For development with a Windows CE emulator we were required to build a custom Windows CE SDK with DirectX support On the actual Symbol PPT 8846 device we used the PPT88xx SDK available from the Symbol Developer Zone at http devzone symbol com 10 E 1 2 The DirectX Software Development Kit SDK DirectX is Microsoft s multimedia platform that serves as both a toolkit and a hardware abstraction layer between a program and a video or sound devices All modern versions of Windows after Windows 95 Service Pack 1 SP1 include some form of DirectX runtime DLL In order to develop DirectX applications the entire DirectX software development kit is necessary in order to obtain the correct static compile time libraries Platform Windows Version SDK Used DirectX Version Symbol PPT 8846 CE NET 4 1 Symbol PPT 88xx 8 0 for CE CE Emulator CE NET 4 2 Custom SRU R 8 1 for CE Host PC XP DirectX 9 SDK 9 0b full Table E 1 DirectX ve
51. data sendto recvfrom 5 Shutdown runtime library WSACleanup WSACleanup Table E 3 Steps to create and use a connectionless UDP socket 2 3 3 Practical Information On our PPT 8846 PDA we were able to open a socket and do data transmission from server PC to the client PDA in other words playback functionality in the RRS system even when the PDA was turned off When the PDA was turned back on the playback through the PDA speaker resumed as if nothing happened However the audio data sent while the device was off was lost We re not sure if the socket remains open and the PDA remains in a sleep state or whether the host just sits and waits for the device to turn back on 32 If we had more time we would have made an event handler for socket events such as turning off the PDA or host computer Windows does have event handling tools outside of DirectShow s special IMediaEvent interface but we didn t have time to learn them For a robust commercial application event handling for sockets and media streaming is essential otherwise the socket routines will run and nothing will be tending to updating the GUI as it paints or buttons that might be pressed As always make sure error checking is done every time a socket function is called Our strategy was to do this error checking in a separate function that passed the sockval to be checked for the SOCKET ERROR case as in Fig E 11 33 E 2 4 MFC Objects CSocket CCeSocket CS
52. devised this format as an idea for describing the steps to making a Windows console application with certain features Description Format The two main sections are the Introduction and the Description section plus whatever other main sections you feel are appropriate such as a conclusion or results section In order to keep all of these documents perfectly consistent I propose sticking to Times New Roman 12pt font with the exact same heading formatting for main sections and subsections as this document The files should be in the MSWord doc format and use the PNG format for inlaid images Content The introduction is one or two short paragraphs which summarize the goal behind the note sheet and summarize the content of the paper The description should be concise and only contain what information is needed Pictures graphs tables and lists of instructions are the name of the game Think of a recipe that is easy to refer to and communicate later In terms of writing for an audience write for people in the following order of importance 1 Yourself 2 Other members of Team Dialect 3 Sponsors at AID 4 Other Computer Engineers or Programmers not used to the concepts you re describing 51 Dialog Window Applications Microsoft Windows CE NET 4 2 Justin Cassidy Revision 2 Introduction Since the Sound Recording Unit we are using has no screen we don t need to make a full fledged Windows application on the remote end Th
53. e click on the file named remoteapp exe and then choose Copy from the Edit menu 6 In the file browser for your remote unit double click on My Computer and Paste the file in that folder using the Paste command on the Edit menu Creating a Startup Shortcut 1 Right click on the icon for remoteapp exe and choose Create Shortcut Now cut this shortcut using the Cut command on the Edit menu 2 On the remote device navigate to the Windows folder then to the Startup folder and Paste the shortcut using the command on the Edit menu 3 Close the ActiveSync program AY Initial Setup Configuring the Host for Remote Devices On the Host computer run the Host s Remote Management Application The list of remote units should be empty at first since no remotes have been configured yet Click the Add Remote button next to the Remote Unit List drop down Give your remote unit a clever nickname so that you can keep it straight from any other remote units for example Rodger Kitten Shane or anything easy to remember Also enter the MAC address for your remote The MAC address is usually on a sticker located on the back of the remote Hosting Multiple Remotes It is possible to host multiple remote units from the same host computer Using the Host s Remote Management Application you can easily choose the remote unit you want to host
54. e a wireless microphone of sorts With a remote unit we intend to record and playback audio with help from a host computer that could be in the same room or across the building on a different floor A doctor can easily make chart notes for a patient from the patient s room A student could take notes in class on his dorm room computer with the single click of a button A musician can record studio tracks for a new album from his bedroom at home 1 1 Overview of Hardware and Software Technologies The IEEE established 802 11 in 1997 to standardize wireless communications Since it is not a new technology it has been tested and revised since its inception for reliability and speed Wi Fi is often used implement large building wide networks with hundreds of computers and printers or simple small peer to peer networks with just a few computers Windows CE is a version of Windows that is lightweight It is designed to run on many different embedded architectures and RISC microprocessors Handheld devices cellular phones and other miniaturized computers have been built on Windows CE In spite of being lightweight it has a broad assortment of applications and libraries of all kinds have been developed to support those applications DirectX has been a part of Windows since Windows 95 when game developers asked for a faster set of tools for programming games in Windows Since then DirectX has found other uses and gained APIs for input dev
55. e steps it follows after the WAVEHDR structs are created A Initialize first buffer and second buffer for the first time a Prepare the buffer with wave InPrepareHeader b DoawaveInAddBuffer waveOutWrite if playing B Start the recording process by calling wave InStart first buffer will start receiving wave data at this point C Starta while buffer loop for filling buffers with recorded data a Wait for first buffer to get done being filled the nested while loop b Unprepare this buffer with wave InUnprepareHeader c Send the unprepared buffer to a file using a MFC object d Waitfor second buffer to get done being filled the nested while loop e Unprepare this buffer with wave InUnprepareHeader f Send the unprepared buffer to a file using a MFC object D Re initialize the first and second buffers with wave InPrepareHeader and wave InAddBuffer DWORD dwBuffLength 8192 Size of each sound buffer WAVEHDR first buffer first buffer dwBufferLength dwBuffLength first buffer lpData new char dwBuffLength first buffer dwFlags 0 WAVEHDR second buffer second buffer dwBufferLength dwBuffLength second buffer lpData new char dwBuffLength 44 second buffer dwFlags 0 Call waveInOpen HERE Omitted PIPA ITAL ITT ETT LATS TTD A ARA Setting up buffers for the first time Prep
56. ecording and playback Control involves handshaking functions between SRU and host recording involves streaming recorded sound over the network to the host and playback involves streaming saved sound files back over the network to the SRU Logic flowcharts can be seen below see fig 3 Host Flowchart and fig 4 Remote Flowchart B Functional Metaphor The RRS ties the SRU and the host intimately together one cannot function without the other Therefore although functions can be tied to either the SRU or the host the functions themselves fall into three categories control recording and playback Control functions for the system consist of the handshaking signals sent between the SRU and Host in order to either establish the initial connection between the two units or terminate the connection once one of the units powers off Recording functions begin with a handshake between the SRU and host followed by initializing the audio stream on the SRU side As the host receives the stream it routes the data to both a file and a virtual sound input A similar handshaking method closes the stream as well as the file and input on the host side Playback functions begin with a handshake between the SRU and host after which the host begins a stream audio to the SRU The host receives the audio from either the virtual audio device s line input or a recorded file and the audio is streamed to the SRU On the SRU the audio is sent to t
57. el API that can be used to program I O on a Windows compatible soundcard It is an integral part of any version of Windows It has functions that send buffers to and from the sound device and simple playback recording functions Unlike the DirectShow or DirectSound APIs it doesn t use object oriented programming techniques Rather each function is an OS call to the sound hardware It uses PCM uncompressed audio formats for sending and receiving audio to and from the audio device For our code here we use two Microsoft Foundation Classes MFC helper objects to store bytes received from the sound hardware You ll want to be comfortable with these objects for the final step where you write from the buffers to a file or to the network Headers Static and Dynamic Libraries All Platforms Headers mms ystem h The main Waveform API header short for multimedia system Static Libraries None Runtime Part of Windows 2 6 1 Recording Using the Waveform API As with other low level APIs writing a working program is a matter of knowing which functions to call and when rather than understanding exactly what those functions do Description Recording Function Playback Function 1 Check if Audio I O devices wavelInGetNumDevs waveOutGetNumDevs exist 2 Select a wave format sInputFormatSupported IsOutputFormatSupported 3 Open the Audio I O device wa
58. en t connected any of the filters together yet No data can flow until we have a source a sink and whatever transform filters connected together to form a graph The basic idea of this process is to enumerate an output pin on an upstream filter an input pin on a downstream filter connect them together and then deallocate the pin variables so we can use them to connect another pair of filters Here s a snippet of code that demonstrates the connection algorithm The filters in this code must already been created in memory or their methods will fail EnumPins PinList TPin OutPin IPin InPin ULONG fetched hr g pAudioCapFilter gt EnumPins amp PinList hr PinList gt Reset Find the output pin on the Audio Capture filter while PinList gt Next 1 amp OutPin amp fetched S OK PIN D RECTION PinDirThis OutPin gt QueryDirection amp PinDirThis if PinDirThis PIND R_OUTPUT break OutPin gt Release hr PinlList gt Release Find input pin on Infinite Tee hr g pInfTee gt EnumPins amp PinList hr PinList gt Reset PinList gt Next 1 amp InPin amp fetched hr PinList gt Release Connect the Audio Capture filter to the Infinite Tee hr g pGraphBuilder gt Connect OutPin InPin InPin gt Release OutPin gt Release Fig E 6
59. ent those features While this Software Development Kit is targeted at PC versions of Windows rather than the embedded versions like Windows CE we can still apply some of the principles demonstrated in the SDK to our project since Windows CE does support a limited set of DirectX tools and libraries including DirectShow 2 2 Learning Curve Since we are new to all of the technologies in our solution there is a fair amount of learning to do before we can program The sample code helps quite a bit with the steepness of our learning curve but it can only do so much Apart from the Microsoft website there is little help on the Internet for us and there are only a few books that promise to offer us any assistance Many classes and utilities are left for us to learn on our own The documentation available for some of the tools we are using is often difficult to understand It seems that some documentation is out of date or just inaccurate so when we read the help files we have to then translate them to apply the directions they give to our build environments For example when we first started building Windows CE images we followed the directions in the help file Through frustrating experimentation we learned that there are a few libraries that cannot be included in the image for emulators along with other small discoveries that caused big problems Whenever we discover a problem or quirk in the environment the documentation or the outpu
60. eout value is reached rather than go on to the next instruction 6A Send data to the server Client Side Buffer consists of a message and its length WSABUF sendbuf sendbuf buf message Some constant length input string sendbuf len strlen message sock val sendto sock Socket identifier sendbuf buf Address of the list of buffers to send sendbuf len Size of the list of buffers NULL LPSOCKADDR amp saddr sizeof saddr y Fig E 16 Listen and accept and a new data socket The send function can also be used but our code uses sendto so we have the added power of specifying the IP address we re sending to over this socket regardless of whether it is bound or not to a specific IP address with bind Using the WSABUF object keeps the string and its length in one place which is also convenient 6B Receive data from the client Server Side sock val recv sock trans Data socket message Some constant length string strlen message Its length 0 y Fig E 17 Listen and accept and a new data socket On the receiving end either this or recv from can be used recvfrom looks like sendto while this looks like send Both are acceptable but these figures show our code as it was originally written in a form we ve verified that works So even if it is inconsistent at least both sides have been tested to work correctly When using dynamic buffers for the input
61. er this will require the main application to have an event handling strategy 2 2 7 Detecting Events The filter graph runs in its own execution thread so your program can continue doing whatever else it needs to do such as print status or diagnostic information while a graph is running Being that the filter graph is in its own thread it is the main programs responsibility to know what that thread is up to DirectShow has its own IMediaEvent interface that allows you to do precisely this Using IMediaEvent methods you can tell the filter graph to send event messages to the main application Although very useful for sending events IMedi aEvent is a DirectShow specific object and cannot be used in event handling for programs with no filter graph 23 Constant representing the code for our filter graph message define WM GRAPHNOTIFY WM APP 1 IMediaEvent q pMediaControl hr hr FGraph gt QueryInterface IID IMediaEvent void amp pMEvent MEvent gt SetNotifyWindow OAHWND m hWnd WM GRAPHNOTIFY 0 tg O Fig E 8 Obtaining the controller for the filter graph and using it to run the graph Every Windows application has a window handle named hwnd or something of that ilk When building GUI applications such as a simple dialog application or a more typical document application this variable is contained by one of the parent classes fo
62. erly connect or create filters step through debugging will almost always reveal a bad return value for some DirectShow method 25 Error checking makes this much easier to see because you can watch the value of the hr variable as it is assigned For extra advice on event handling deadlock might occur between two threads if any system calls are made in the WindowProc function DirectShow methods don t make system calls to my knowledge so this only comes into play if you try calls to lower level APIs such as Windows Sockets or the Waveform API in your WindowProc function The Microsoft documentation states that DirectX shouldn t be used in high security computing environments and the deadlock issue above might be one reason why For high security sound programming the Waveform API is more appropriate 26 E 2 3 Windows Sockets The concept of sockets was created by Unix network programmers in the 80s and has since been adopted by every major operating system that uses networking in any form A socket is a sort of network jack created by an operating system For instance a TCP IP socket is given a port number and an IP address Any data sent to this socket using the proper functions will be sent using the socket s protocol port and address information The socket might be set to listen for incoming connections or to make a connection to a remote machine A good synopsis of a socket is that it contains all necessary addressi
63. es used by eMbedded C must either be included with the Windows CE SDK or built from source code using the eMbedded C compiler 1 4 5 Debugging Helper Tools and ActiveSync Even if the IDE isn t the same the eMbedded C debugger shares all the same major functionality with its Visual C counterpart There is also an error lookup tool and a registry editor that work exactly like 14 the XP counterparts One important difference is that the Windows CE registry editor runs from the development machine and must connect to the remote device using Microsoft ActiveSync Using ActiveSync with the PPT 8846 is a chore It took random fumbling around with the COM port settings in the Windows Device Manager The final settings that worked for us were as follows 115200 baud 8 data bits No Parity 1 Stop Bit Xon Xoff flow control FIFO disabled this was the main problem at the port settings tab click Advanced 15 E 1 5 Windows CE Platform Builder and Windows CE Emulator The purpose of the Windows CE platform builder is twofold it is used to build Windows CE operating system images from a user selectable catalogue of features It also builds a specialized SDK for your platform that includes documentation and libraries for precisely the features you include in your platform build Since the STANDARD SDK default platform didn t include DirectX libraries we needed to build a new one for the purpose of testing remote end code o
64. ese are technical notes on Windows programming and event handling targeted for someone with no prior Windows programming experience using the eMbedded Visual C 4 2 development environment The notes describe the development of a simple button based dialog window application Although a console application was also considered embedded Visual C does not document how these are created and for accepting simple keyboard scancodes dialog applications seem to do just as well as the stdio scanf solution Description Project Creation File gt New gt WCE Application gt Dialog gt Windows Sockets The files created set up the dialog box with a default TODO message which can be removed using the Resource Viewer Editor tools User Interface By clicking the Resource Viewer and clicking on the dialog resources you have access to what the dialog window will look like and you can even add buttons or text simply by hand These changes are stored along with accelerators in resource files that are called by the C code The changes are not made in the C code itself which can be confusing Double clicking on a created button will make a class method in the proper code file that can be edited Every new button created has an incremented ID and this can be changed with a right click not sure if this matters Each button and probably each GUI object has special events associated with it and once they are defined to exist a proper class me
65. fers for the first time H ERE 0 uN ECS 3 Update wait on and then reinitiali e buffers HERE ends Fig E 42 Our buffer loop itty witty baby version 46 This easier loop makes the timing of our algorithm clearer Each time we readin first buffer and second buffer with a buffer size of 8k we ve read in 16k Experimentally this gives us about 0 32 seconds of audio every time we read in a buffer This is where the nLoops value comes from calculated from the number of seconds we want If our loop were in a function we would want this time in seconds to be an argument to that function For a smarter program this loop would run in its own thread and run indefinitely until the program received a message that it should stop like say from the network computer sending or receiving data using this loop You might be interested just how we would add file writing functionality or network functionality to a loop like this That step is next on our list 7 Read or write a buffer to an outside interface This is the other tricky part about writing record or playback routines There are countless ways to read in information from files buffers streams or networks The charm of using the MFC classes is that the objects we use are relatively simple and make way for short and easy helper functions if they are needed at all The following code initializes the objects and illustra
66. forms a quick diagnostic battery life check connecting to the host The SRU can then record or play sound with the press of a button When in record mode the microphone picks up sound and the sound is transmitted via DirectShow over the network connection When in play mode the host will stream audio to the device for it to play through its internal speaker Recent recorded audio streams are stored on the host and the driver can track forward and backward through the stored streams during playback B Operational Metaphor 1 First Use The driver software is installed on a computer designated to listen to the SRU a host computer An IT professional will run the driver software and configure it with one or more SRU s network addresses and names This will enable the SRU selected in the driver software to communicate with the host when the unit is powered on While a host can be configured to communicate with multiple remote units note that only one remote unit should be used at a given moment with the same host 2 Powering On Off The SRU unit has an on off switch for turning on the unit A 3 7V rechargeable Lithium lon battery powers the unit When it is turned on it connects to the host computer via an ad hoc wireless network connection If it cannot find a host to communicate with the activity LED will flash red and the SRU will need to be powered off 3 Recording Sound The SRU uses an internal microphone to record audio
67. g While presenting our project at the University of Idaho s Engineering Expo we were able to test out system in a crowded room with other Wi Fi projects also running in the same room Mr Cassidy carried the handheld around the auditorium and reached an approximate maximum distance of 150 feet from the host with minor obstructions and the host computer and the handheld maintained constant connection and communication However when Mr Cassidy carried the handheld unit through the auditorium entrance and began to walk down the brick corridor the two computers lost communication On the other hand when the remote was brought back within range of the host they began communicating again and transmitting data We felt that we had satisfied the network test over distances and noisy network conditions We also tested latency of the system by snapping into the microphone on the handheld unit and holding the handheld close to the speakers on the host In this manner we recorded a snap and its respective echo through the system We then looked at the waveform sample in a sound editing program and measured half a second of total system latency We also calculated the total theoretical system latency We are recording at about 44Kilobytes per second On the host computer there is a 2Kilobyte buffer and on the handheld unit there is a 6Kilobyte buffer The total latency due to audio buffering then is the total size of the buffers divided by
68. he on board sound module and played through the internal speaker On the SRU the user has the ability to cycle through 10 stored files on the host for streaming playback When the user chooses to play a different recorded session the SRU handshakes with the host which skips to the desired file Wait for SRU network connection SRU Power on Wait for SRU Command Host Boot up load driver SRU Record Reproduce SRU Power Off recorded file to SRU incoming stream at mic in and record to file SRU Record or Stop SRU Next Track SRU Play or Stop SRU Prey Track Skip to previous track Fig 3 Host Flowchart This chart shows the logic for the host application running in the background This application would start with Windows so that it is ready and waiting for a remote unit all the time Power On Connect to host blink green LED Blink red LED wait for power off Connected Ready green LED solid on Disconnect from host power off Fig 4 Remote Flowchart This chart outlines the logic flow for the Handheld application passing the Through message remote asks the host to perform control procedures for recording or playback C Functions 1 Control Function
69. he reference material included with the API documentation included with versions of Visual Studio We assume readers have access to this documentation also available on the MSDN website as well as a basic understanding of Windows drivers processes and threads C class syntax and related terminology It will help you to read our Windows Development documentation as well as Table E 1 for the various versions of DirectX employed in the different versions of Windows 17 E 2 2 DirectShow Microsoft DirectShow is a media transport API that we believed was capable of implementing all audio compression network transfer and audio playback functionality on both the host side and the remote side Although most of our development time was spent trying to develop DirectShow sample code into a form suitable for host and remote development we ran into significant problems with how DirectShow transfers data between its component objects that made rapid development of our RRS system impossible Regardless of its absence from our final solution since we spent most of our time working with DirectShow we have gathered enough documentation to discuss how to develop DirectShow applications and describe how DirectShow is useful in practice rather than in theory Headers Static and Dynamic Libraries All Platforms Headers dshow h Main DirectShow header streams h Used for streaming applications Static Libraries strmiids lil CLSIDs and err
70. her Remember that even with the hardware metaphors DirectShow employs these objects are software code and the process of using them doesn t necessarily work like it would real hardware After the filter graph is allocated and the filters are connected the main program calls a Run method and the filter graph will run in its own thread creating or collecting audio or video data as the main program continues doing other things The main program must use some form of event handling to listen to any messages the graph thread might send out in order to determine when it is done with its task 2 2 2 a Filter Varieties There are three main varieties of filter transform filters source filters and sink filters The transform filter is what one might associate with the actual hardware concept of a signal filter it takes an input stream and manipulates each sample of that input stream in some way Two sample transform filters included in the DirectShow SDK are the Gargle filter and the WavDest filter 18 2 2 3 The Gargle filter manipulates sound samples to sound gargly as one would expect The WavDest filter does no modifications to the stream of bytes it receives but it does keep track of the samples it obtains so that after all data has made it through the filter it can append an appropriate wave file header to the beginning of the stream It doesn t write to a file itself it must be connected to a separate file writer filter In this se
71. hwin amp first buffer sizeof WAVEHDR Do RetVal wavelnAddBuffer hwin amp first buffer sizeof WAVEHDR Do Poll to see when buffer is done being while second_ buffer dwFlags amp WHDR_DONE wavelnUnprepareHeader hwin amp second buffer sizeof Device ha WAVEHDR s Size of t Device ha WAVEHDR s Size of t ndle tructure he buffer ndle tructure he buffer written to TRUE WAVEHDR Call MFC method to write first buffer to a file or socket right HERE omitted Prepare the second buffer while the first one is filling up RetVal wavelnPrepareHeader hwin amp second buffer sizeof WAVEHDR Do RetVal wavelnAddBuffer hwin amp second buffer sizeof WAVEHDR Do cnt fi Fig E 41 The buffer loop Device ha WAVEHDR s Size of t Device ha WAVEHDR s Size of t ndle tructure ne buffer ndle tructure ne buffer Hopefully you see that this is just a typical while loop setup where you initialize a variable in this case the buffer before entering the loop for the first time and then you update the buffers every time the loop iterates It really simplifies down to something like this cnt E nLoops DESIRED TIME while cnt lt nLoops Initialize buf
72. ices networking graphics audio and other multimedia Since Wi Fi Windows CE and DirectX are widely used there is plenty of documentation available Though our solution incorporates 802 11b it never really directly uses or manages the Wi Fi connection or hardware That task is left to Windows In that respect we could use just about any type of network connection and as long as Windows can support it our solution will achieve similar results DirectX has long been a part of Windows and assuming it includes backwards compatibly with older programming interfaces as it has done in the past our solution will still function with new versions of DirectX The same goes for new versions of Windows CE These benefits make the gauging the RRS system s end of life difficult 6 1 and 6 2 2 Design 2 1 Windows CE Platform Builder and DirectX The Windows CE toolkit includes a Platform Builder for making custom versions of Windows CE that have only the libraries and headers we need for our system We are also using eMbedded Visual C 4 0 a compiler that targets several different embedded architectures including MIPS x86 SH4 and ARM platforms There is also an Emulator that we can use to load custom OS images and run and test our application The DirectX toolkit includes plenty of sample applications and source code that demonstrates the unique features available to DirectX programmers as well as the libraries required to implem
73. ilds an OS image for the device along with a SDK for the eMbedded IDE Steps I Build the Custom OS Image 1 Run Platform Builder and select the New Platform Wizard from the File menu 2 Choose the Remote Media Server build profile and make sure 802 11 support is included in the network options 3 Look through the Catalog bar docked on the right hand side of the IDE and select the features you wish to add to the operating system The following is a list of features built into the OS image we used not all of which may be necessary DirectShow Core DirectSound ACM Audio Compression Manager 4 Build the image This took 30 minutes on a 1 7GHz 512MB RAM system II Build the SDK 1 Choose Platform gt Configure SDK and make sure eMbedded C support is included as well as all library options ATL MFC etc except for the NET framework Remember the name you give your new SDK ours was SRU R 2 After this is done choose Platform gt Build SDK This takes 10 15 minutes on a 1 7GHz 512MB RAM system III Set up the Emulator Image with eMbedded C In eMbedded C under the list of SDKs you should see an option for the SDK you created In our case we were able to select SRU R for the platform and SRU Emulator for the device from the drop down menus If you ve added all the right features you ll notice the Class Not Registered errors disappear when you run and test your programs 60 IV Set up the OS on a
74. in hardware testing but rather software validation and instrumentation All our instrumentation verification methods for the separate audio and networking routines will be clearly documented in simple technical notes sheets These sheets also illustrate how the build environment is created along with the exact software used 3 1 SRU Playback and Recording Routines Any time the SRU initiates a playback or a recording session data will be streamed to and from the SRU and the host Since the data stream will consist of a DirectShow audio over TCP IP and 802 11b we can abstract the network transfer apart from the actual sound functions Whether sending from the host to the remote unit or vice versa the transfer code will be the same Network routine testing is discussed in 83 3 Ensuring audio fidelity for speech recognition is discussed in 3 4 The playback and record routines need to be both functional and responsive and this can be verified through step by step debugging in tandem with testing Although functionality can be tested on the emulator its speed is a limitation so only the actual device will measure responsiveness properly 3 2 Host Software and Virtual Audio Device The host software consists of a front end for storing SRU profiles a network driver for receiving streaming audio from the host and a Virtual Audio Driver We are using a 3 party VAD that hasn t been tested explicitly on Windows XP but appears to work for a
75. lasted If we consider the project s lifecycle to be tied to this architecture then it would be the factor that determines the project lifespan of the RRS However writing for Windows CE dictates that we are writing software for an operating system rather than an underlying architecture So although AID will likely market actual screen less devices with the SRU software on them the true end of life of the RRS will occur when they cannot easily put the remote software on a standard newer Windows CE device or update the software for newer versions of Windows 6 2 Software The life of the system is also heavily tied to the software and support availability of Windows We should consider the remote software s end of life as tied to the Windows CE NET 4 2 platform as we should consider the host software s end of life as tied to Windows XP Microsoft has strict end of life policies on its software and operating systems Below is a table of their product lifecycle support dates The most important of these is probably the end of life date for the eMbedded C 4 0 IDE used to build this suite We predict using a newer Microsoft IDE will fail to build the software using the same process we documented and require copious amounts of tedious testing and debugging TABLE 2 END OF LIFE ESTIMATES FOR HARDWARE AND SOFTWARE TECHNOLOGIES 1 Product Description End Support Date Microsoft Remote OS with 30 June 2008 Windows CE DirectX N
76. lear detail Description Client Sender Function Server Receiver Function 1 Initialize the runtime library WSAStartup WSAStartup 2 Create the socket socket socket 3 Set Socket Options setsockopt setsockopt 4 Bind address to socket None implicit bind bind 5 Connect to server Listen to client connect listen accept 6 Send receive data send recv 7 Monitor the socket state select Select 8 Disconnect Close socket shutdown Shutdown 9 Shutdown runtime library WSACleanup WSACleanup Table E 2 Steps to create and use a connection state TCP IP socket 1 Initialize the Runtime Library Call WSAStartup with no arguments and Windows knows you are going to be using sockets This is specific to Windows Sockets programming but it is not a version 2 function 2 Create the Socket Create and initialize an actual socket and a return value holder SOCKET sock sockval sock sockval 0 sock socket AF INET SOCK STREAM T RROR if sock SOCKET sockval WSAGetLast Error Handle the error or return exit PPROTO TCP Fig E 11 Creating a socket and checking for errors SOCKET is just a glorified way to specify an unsigned integer that describes a socket value If this or any other socket function fails the version 1 function WSAGet Last Lookup tool to see what was wrong Error will give you a
77. lity also for testing on the actual remote unit 3 4 Fidelity and Latency Testing DirectShow s Audio Compression Manager filter accepts the audio compression format as one of its arguments For particular file formats and sample sizes we can test transmission performance versus recognition quality by simply changing the argument to the ACM filter Our goal is to get accurate speech to text synthesis in real time but if this proves difficult we will optimize for fidelity rather than 7 performance Having an accurate transcription is the highest priority at the hospital more so than a quick performance Latency testing will occur in a number of different indoor and outdoor environments in order to gauge the usefulness of the RRS in a variety of situations Our goal for real time operating distance is 100 feet and we need to be sure this goal is met under common operating conditions 3 5 System Testing After the network and audio routines are completed we will need to validate our final design The RRS interfaces need to be easy to use for a doctor easy to quickly maintain on the host end by trained IT staff and intuitive enough such that someone who can operate a portable CD player or PDA won t have trouble using the SRU Although the scope of our senior year project dictates we may not be redesigning the GUI interface and the hard PDA interface we will at least validate how well they suit the task 3 6 Results of Testin
78. ll our uses However part of the testing process will be making sure the received raw audio data finds its way to the virtual audio driver and that the software works as advertised The Host software will need to be tested initially on the OS specified in the requirements document Windows XP in an ad hoc network configuration with the remote unit Initial Host software testing will be with a hardware audio interface to eliminate possible problems related to the VAD itself Every functionality of the remote unit will be tested such as record playback track forward track back power on and off to ensure the host software responds in the specified manner After the Host software is verified the VAD will be selected in place of the hardware sound device and the same tests will be run on the Host software using the VAD using various different 3rd party packages recording from the VAD audio interface to ensure the functionalities we require of the VAD work correctly 3 3 Networking The job of the DirectX APIs is to abstract the hardware and in this sense once we have verified the network code over Ethernet we can take this code and merely change the data link layer transport medium Our emulator only has Ethernet capability but if we can step by step debug our routines on that medium we can simply change the network we re using once we adapt our routines for the PDA hardware Our development suite has remote step through debug capabi
79. mber of bytes was read m pArchiveOut Write lpData nBytes nReadBytes m pArchiveln Read lpData nBytes Fig E 26 Constructing a CSocketFile object and connecting it to the CSocket 37 E 2 5 DirectSound Buffers DirectSound is part of the Microsoft DirectX API and is used for directly accessing audio playback and capture buffers on any of the system s hardware sound devices that support the DirectSound API A sound buffer is a memory location that can reside in system memory or directly in the sound hardware s memory that is used for storing raw audio data In a playback buffer the application writes the audio data into the buffer and calls the Play function on the DirectSound device to playback the audio through the system s sound hardware In a capture buffer on the other hand the sound hardware writes the audio data to the buffer and the application pulls that data out of the buffer for it s own use There are two types of playback buffers Primary and Secondary There is only one Primary buffer into which multiple Secondary buffer s audio data can be combined mixed for playback For most applications Secondary buffers should always be used for audio playback in order to allow other applications that are running simultaneously on the system to playback sound as well Headers Static and Dynamic Libraries All Platforms Headers dsound h Main DirectSound header dsutil h included in the DirectX
80. ment for more information 2 2 7 Running the Graph In terms of the main programs logic the most important thing a programmer needs to plan on is event handling As soon as the filters and graph are created and connected you grab an IMediaControl pointer from the filter graph object and use its methods to Run and Stop the graph IMediaControl q pMediaControl hr g pGraphBuilder gt QueryInterface IID IMediaControl reinterpret cast lt void gt amp g pMediaControl hr g pMediaControl gt Run Fig E 7 Obtaining the controller for the filter graph and using it to run the graph QueryInterface isa very important method used in many DirectShow objects It is used to allocate memory for a set of class methods used to operate on the calling object Here we create a IMediaControl object named y pMediaControl to control the g pGraphBuilder filter graph object As the variable name might suggest it is useful to put the IMediaCont rol pointer into protected class memory or global memory so you don t have to worry about passing it during calls to the event handling function Up to this point if you ve made a program that implemented the filter creation and filter connection techniques created the media controller and called Run you would have a working graph It will simply run until the stream ends Chances are an application will wish to have the option to stop this stream before 1t is over howev
81. mode the samples are sent and the filters act synchronously on the data as it is moved down the graph A Poor Streaming Platform Although DirectShow is designed for both synchronous streaming and asynchronous non streaming applications Microsoft later designed Windows Media APIs which are centered around streaming their proprietary formats and as such DirectShow remains an immature platform for developing streaming applications The problem is that the filters required to implement streaming and negotiation between IAsync and Mem interfaces are non existent For example it is relatively trivial to construct a graph that takes an input WAV file and converts it to MP3 with the MP3 compressor filter However if that WAV data is streaming 19 right off the Audio Capture filter the developer cannot use the Microsoft MP3 compressor because the Audio Capture filter operates in push mode while the MP3 compressor can only handle asynchronous reads from a file pull mode To further complicate things it is not readily apparent which data flow methods and pin types a filter employs without jumping headlong into documentation Our group might have chosen to develop a sink to source parser filter that makes a buffer that the downstream portion reads asynchronously Unfortunately this would have taken more time than it would take to implement the RRS outside of DirectShow due to the large number of methods needed to instantiate
82. mote unit but that might only protect it while it is not being used TABLE 5 FMEA TABLE OF RATINGS Severity Occurrence Detection RPN Phys Damage 7 4 9 252 Host OS failure 5 3 10 150 Mic Malfunction 3 2 7 42 Low Battery Life 5 8 1 40 Out of Range 5 6 1 30 Library failure 5 2 2 20 External failure 5 2 1 10 No soundcard 5 2 1 10 Memory fail 5 2 1 10 Auto Start fail 5 1 1 5 DirectX absent 5 1 1 5 Tracks unavailable 5 1 1 5 HD full 4 1 1 4 Resources in Use 3 1 1 3 V SOCIAL IMPACT A Health and Safety Issues As this speech recognition unit will be used in hospitals as a transcription tool there is the chance that it could be a vehicle for the spread of infection Recently 10 cellular phones were found to spread dangerous strains of bacteria in hospitals 2 Apart from good hygiene practices our documentation will clearly outline effective methods of sterilizing the wireless unit Cellular phones that operate in the 900MHz band as well as other wireless devices have been known to disrupt pacemakers defibrillators and hearing aids 3 However higher frequency PCS phones operate on much lower power than their predecessors and have an insignificant effect on medical and life critical devices 4 Devices that use 802 11b radios and technology are similar to PCS phones in this regard With any portable audio device there is an issue of possible hearing loss when using headphones particularly bud earphone
83. n actual device This is a matter of using Tools gt Configure Platform Manager and setting up the transport schemes properly For our PPT 8846 PDA we believe Symbol makes it impossible to flash the OS through Platform Builder They have their own tool for this task requiring you to buy only supported binary images from Symbol You may have more luck with a different PDA If your device is set up correctly you can use your SDK to build to your actual target device in eMbedded C in exactly the same way described in part III above 61 Configuring a Wireless Network Between a Host and a PDA Justin Cassidy Revision 2 Introduction It would be nice if wireless peer to peer networks were as simple as two computers together in a room Unfortunately it s slightly more complicated This process describes how to set up a peer to peer wireless connection between a Windows XP host and an 802 11 wireless equipped Symbol PPT 8800 series PDA using static IP addresses Process Host 1 Turn on your wireless network card or if using a laptop insert into your PCMCIA slot 2 Goto Control Panel gt Network Connections 3 Right click the Wireless Ethernet Connection icon and click View Available Wireless Networks 4 At the list of available networks click Advanced 5 Below the list of preferred networks click Add 6 In the box that appears do the following a Give your network an arbitrary name Ours was Locus
84. nctions and methods it calls works Having a DirectShow network filter is wonderful but you won t be able to debug it unless you know how it uses Winsock to create a socket and transfer network data Objects can be powerful tools but they certainly aren t crutches for the uninitiated like we originally presumed 2 7 3 Object Oriented Programming As I mentioned previously there are ways to take object oriented programming to serious extremes as with DirectShow However not all of Microsoft s objects are bad CF ile CSocket and CArchive are wonderful tools for encapsulating the functionality of a lower level class into an object that will do most of the tedious set up for you These objects are easier to work with in dynamic memory than many smaller variables as they can be allocated and deallocated together as necessary API objects generally have a steep learning curve This isn t helped by the dense brief documentation in the MSDN library and the lack of sample source code demonstrating how the objects are used Furthermore the Microsoft way of assigning CLSIDs to objects and storing them in runtime libraries with references in static libraries is very confusing to work with at first These libraries aren t portable like the source code and must be rebuilt and reorganized into new projects when moving between C NET and eMbedded C 49 F TECHNICAL NOTES SHEETS Technical Notes An Example Dialog Applications Instan
85. nd Capture buffer once the buffer has been configured the buffer contains no audio data and is ready to be filled by the sound device Audio Capture begins one the Play member of the Capture Buffer is called The Play member takes one argument which is a flag that can be set to DSCBSTART LOOPING This flag allows the sound device to treat the buffer as a circular buffer and infinitely capture audio to the buffer until the Stop member of the buffer is called hr pDSCB gt Start DSCBSTART LOOPING Fig E 34 Start audio capture to the Capture Buffer 10 Lock Buffer Section In order to access any of the data contained in the DirectSound buffer you must first call the Lock member of the buffer to lock that memory space to allow read write access of the application The Lock member of both the Capture and Playback buffers are identical The first two parameters are integers that indicate the byte offset of where to begin the locked portion of the buffer and the number of bytes to lock after that offset The last four parameters are memory pointers and integers returned by the Lock command a pointer to the first locked portion of the buffer and the number of bytes in that portion and also a pointer to the second portion of locked buffer and the number of bytes in that portion The reason two portions are returned is that if the buffer is circular and the number of bytes requested in the Lock exceeds the end of the buffer the locked sec
86. nd a Windows XP desktop host computer The user can transmit audio over the Wi Fi connection to the host computer that can perform any of various audio tasks with the data archival voice recognition or audio recording The purpose of this project was to replace an existing system that is based on a USB connection rather than a wireless network connection The trouble users have with the USB system is that the user has to stay tied to a desk in order to use the system B Intended Use The intention for this project was to replace the existing system which is being used in a hospital by doctors The users of the existing system primarily take advantage of a voice recognition program to make notes in electronic charts for their patients With a wireless network connection users would be able to wander around a room This work was supported in part by the Electrical and Computer Engineering department at the University of Idaho Moscow Idaho and by Advanced Input Devices Coeur d Alene Idaho J M Cassidy is a graduating senior in Computer Engineering at the University of Idaho Moscow Idaho 83843 USA phone 208 883 4455 e mail cass0664 uidaho edu I D Olson is a graduating senior in Computer Engineering at the University of Idaho Moscow Idaho 83843 USA e mail olso4398 uidaho edu T R Stear is a graduating senior in Computer Engineering at the University of Idaho Moscow Idaho 83843 USA e mail stea7935
87. ng connection and state information for data transfer between two computers Once it is set up the two computers can use a standard set of functions such as send and recv to transmit data back and forth Windows Sockets or Winsock is the Microsoft adaptation of the earlier Berkeley Unix sockets program Winsock is a low level API for programming network transfers between two Windows computers and is standard across all Windows platforms Socket functions are actually OS system calls in fact open sockets on ports within a certain range 0 to 5000 are handled directly by the operating system and will remain open even after a program is shut down There are two major versions of Winsock version 1 and version 2 Version 2 is backwards compatible with version 1 but has a number of new Microsoft additions to the original set of Berkeley Unix socket functions We encountered build issues with Version 2 on the remote side and most of the Microsoft additions didn t seem useful for our purposes Therefore we used solely version 1 functions on both platforms and used version 1 libraries with the remote program Most but not all version 2 functions act similar to version 1 except with more parameters and a WSA prefix socket and WSASocket send and WSASend etc As this is a low level API the functions may be confusingly named but the method and code itself remains simpler than object oriented code Anyone who knows C should
88. ng the Target Device using Platform Manager All the Windows CE development tools use the Windows CE Platform Manager to configure the target devices The Emulator comes pre configured but other CE device profiles might not work off the bat due to problems with serial or wireless communication To access the platform manager select the Tools menu and then select Configure Platform Manager Then select the profile you wish to modify for the remote device choose PPT 800 Device In particular we had trouble communicating over the serial port and the Symbol documentation was of no help whatsoever The Platform Manager settings that worked for us are as follows Transport Server TCP IP Transport for Windows CE Configure Connection over Serial defaults elsewhere Startup Server ActiveSync The target device can also be configured to use a wireless connection if the device is currently connected to your wireless network Just put in the device s wireless address in the TCP IP Transport Server options 1 4 4 Static and Dynamic Libraries with Windows CE As with a DLL project in Visual C NET a DLL project for eMbedded C creates a DLL file and a lib file Also as with other Windows development the lib stub created by this DLL must be linked into applications that want to call the DLL Note that lib files and DLL for the various CE architectures are completely different from the ones compiled for Intel x86 architectures Librari
89. ng them to the filter graph pFGraph gt AddFilter g pSend Network Send Filter The second argument is just the name that your filter is given within this filter graph If g_ pSend is not pointing to a created filter in memory this statement will fail 7 Remember to do error checking any time you allocate memory In the IDE you can check the return values of CoCreateInstance AddFilter and a host of others by creating a test value and setting it equal to the return value of your function under test Since these methods return a value of type HRESULT just do something like this hr CoCreateInstance CLSID FilterGraph NULL CLSCTX_INPROC_SERVER D IGraphBuilder void amp pFGraph if FAILED hr Return an error Fig E 5 Error checking with the return value of a memory allocation function FAILED is a macro that simply checks if hr is greater than zero The convention is that a HRESULT of 0 also defined as S OK is the non error condition while anything else is an error Just to reiterate Build your DLL initialize COM create the filter graph and the filters set up the each filter s unique parameters add the filters to the graph and do error checking along the way to make sure you didn t forget anything So you ve got your filters in a graph Now what do you do 21 2 2 6 Connecting the Filters Y ou might have noticed we hav
90. no arguments and Windows will know you re done using the sockets runtime libraries for now While you may start and shutdown sockets many times while your program runs chances are you ll only initialize and shutdown the runtime libraries only when you first start your program and when your program closes or exits with an error 2 3 2 Using Datagram UDP Sockets We considered using UDP or datagram sockets because they re easier to set up than connection sockets Furthermore because they have no overhead from a connection state they transmit data faster than a TCP socket However datagram sockets do not guarantee data gets from one computer to the next It works more like the postal service information may be sent but not necessarily received For purposes of transcription it is critical to receive all the data that was sent so we chose to use TCP sockets rather than UDP While we won t go into details about the code required the following table is provided as a reference for the order in which to call socket functions so that a simple program can send and receive data on these connectionless sockets Note the lack of connection steps as they aren t needed for datagram sockets Description Client Sender Function Server Receiver Function 1 Initialize the runtime library WSAStartup WSAStartup 2 Create the socket socket socket 3 Set Socket Options setsockopt setsockopt 4 Send Receive
91. nse it is a transform filter as well Source filters are specific for the device drivers on a Windows XP system A sound card will have an Audio Capture Filter and an Audio Renderer filter a video capture card will have a Video Capture filter and so on Any Windows supported audio or video hardware can have a source filter created for it by DirectShow To use these sources in a program you must enumerate the available devices in a particular category and then grab the device you want and include its filter Source filters exist for capturing streamed network data as well these require no device enumeration by the main program as they enumerate the network card within the filter itself Furthermore a source filter could point to an input file such as the File Renderer does Sink filters are the filters that take the input stream and write 1t to an output stream or buffer These might be enumerated devices in the same sense as the source filters described previously or they might be something as simple as a file writer The DirectShow version of the RRS used a network sender filter that essentially was a sink to the network 2 2 2 b Pins and Media Types As described earlier all DirectShow filters have pins These pins have methods that are used to connect themselves to other pins or to other input or output data streams and buffers Most transform filters have one input pin and one output pin while sound card source filters have any num
92. ocketFile and CArchive The CSockets interface is built upon Windows Sockets and is a higher level of abstraction than normal Windows Sockets making it simpler to use CSockets uses a subset of the CAsycnSockets interface and is a more programmer friendly interface The advantages of CSockets over CAsyncSockets is that it is easier to use and guarantees all data sent will be received and in the same order that it was sent Using this type of socket connection the sending and receiving of data between client and host can happen asynchronously and all received data is stored in a buffer until the client or host reads the data out of it s receiving buffer Headers Static and Dynamic Libraries All Platforms Headers afxsock h Main AFX sockets header Static Libraries none Runtime Part of Windows 2 4 1 Using CSockets The basic steps of using the CSocket are to fist establish a connection for the CSocket between the server and client applications Then bind a CSocketFile to the CSocket then bind a CArchive s to the CSocketFile and use the CArchive s for sending and or receiving data to and from the socket connection The CSocket CSocketFile and CArchive objects are all AFX based objects which means that AFX must be initialized in the application before the objects can be used Description Client Sender Function Server Receiver Function 1 Initialize
93. ofa CArchive object Remember that the CSocket object is replaced in Windows CE by a CCeSocket object that has very minor differences in how it handles its internal state 8 Close the Audio I O device waveInStop hwin waveInUnprepareHeader hwin amp first_buffer sizeof WAVEHDR waveInUnprepareHeader hwin amp second buffer sizeof WAVEHDR waveInReset hwin waveInClose hwin Fig E 45 Audio I O shutdown code If you are closing an audio stream for good make sure to call the functions in this order wave InReset may not be necessary here as it just resets the audio device this causes the audio device to go back to the head of whatever buffer it was playing 2 6 2 Hints Tips and Closing Remarks The buffer loop is the most important part of your audio I O routines Every time you allocate a buffer for the audio device you should do error checking which was omitted from the code samples above Generally the I O device has very limited resources so don t try to send 10 or so buffers with 8kB memory each to the device with wavelnAddBuf fer because resources will run out and eventually these calls will start failing After running these routines it is important to deallocate the MFC objects you created in memory with the new keyword Objects left in memory are the source of memory leaks and they will cause your program to shut down with an error after your audio operations have comple
94. oftware we cannot release the applications for commercial use In the cost analysis however we account for the cost of the development tools such that a person could develop the project further and for commercial use VI SPECIFICATIONS NOT YET MET The specifications we did not meet in our implementation are listed below e Software command interface to control IBM s ViaVoice voice recognition software e Track management interface Given more time and had we initially selected the method of solution we finally used these specifications would likely be functional today As it is these may be somewhat simple to implement for another team of programmers VII FUTURE MODIFICATIONS Given more time for this project this list of additional features would likely have been completed A Host e Support for multiple simultaneous remote hosting e Support for WLAN in addition to ad hoc e Support for WEP keys e Create custom docking software to configure remotes and their addresses e Advanced interface for controlling Voice Recognition programs other than ViaVoice B Remote e Change to a headless device implementation e Support for WLAN in addition to ad hoc e Support for WEP keys e Manufacture a new plastic shell and rubber buttons for the playback and record controls as well as the volume adjustment e Add support for other handheld computing platforms Axim iPaq Jornado palmOS etc that are equipped with speake
95. ogramming to make the connection and Waveform API for audio capture and playback we had constructed a system that accomplished our two major goals in this project audio capture and transmission from a handheld device over Wi Fi and playback of the original recorded sound from the host back to the remote unit D Functional and Non functional Parts of the Project There were a few other goals we had set our minds on in the planning stages of this project We also wanted to tie our program into a third party voice recognition program for dictation Our sponsor recommended IBM s ViaVoice for this end since that is what they use in their solutions We also had plans to control tracks or a history of recorded or transmitted sound clips Since no data is stored on the remote the archival or read back would have to be managed on the host end We learned that we could likely control the host s playback and recording operations from the remote unit through message passing a standard Windows procedure that allows an application to perform concurrent operations To manage the tracks or sound clips we had planned on creating a small table of file pointers every time the host application started In this manner skipping tracks from the remote would simply open a new sound file from the chronological listing and begin to play it back over the network This would need a drastic modification to tie directly into the voice recognition program
96. or messages for DirectShow objects strmbase lib Base classes used to develop filters For release builds only strmbasd lib Same as above but for debug builds only Runtime Installed DirectX 8 0 or later 2 2 1 The Microsoft Common Object Model COM Just about everything in DirectShow is a class object Microsoft has a standard for designing these objects called the Common Object Model or COM The important things for application developers who use these objects to know are how to initialize them and how they re stored in memory A quick and dirty summary use CoInitialize NULL to initialize the COM subsystem DLLs and then use CoCreatelnstance to create instances of the objects you need When you re done use the object s Release method to deallocate object memory and CoUninitalize NULL to shutdown COM Once the DLL is registered with Windows it creates global values in the Windows Registry so other programs know where to find it This process will be described once we have described particular DirectShow objects in more detail 2 2 2 Filters Pins and the Filter Graph DirectShow is based around the idea of software filters These filters are objects that obtain data from hardware manipulate it in a vast variety of ways and then write it to any sort of buffer such as a network or audio buffer or a file These filters are allocated under a filter graph object and then the filter s pins are connected toget
97. propriate return call to the lower level handler Adding a condition to check for WM_GRAPHNOTIFY messages will allow your application to handle the messages from the filter graph The final function looks like this LRESULT CDialogappDlg WindowProc UINT message WPARAM wParam LPARAM lParam switch message case WM GRAPHNOTIFY HandleEvent break return CDialog WindowProc message wParam lParam Fig E 9 Our application s WindowProc function 24 WM GRAPHNOTIFY only tells us that something has happened with the filter graph not what that something might be So it calls a HandleEvent function we make to determine what really happened n our filter graph and make the appropriate decision HandleEvent calls MediaEvent GetEvent to obtain the filter graph s state We then take action based on what this state is All the following HandleEvent function acts upon is EC COMPLETE which determines if he entire stream went through the graph or EC_ USERABORT which would be sent if the IMediaControl Stop method was called somewhere Pei HRESULT CDialogappDlg HandleEvent HRESULT hr long evCode paraml param2 hr pMEvent gt GetEvent amp evCode amp paraml sparam2 0 while SUCCEEDED hr hr pMEvent gt FreeEventParams evCode paraml param2 if evCode
98. r and adding them to a completely separate eMbedded C project 2 7 2 Microsoft APIs Having the Windows APIs mostly supported across both Windows CE and Windows XP was very useful For low level code such as Windows Sockets and the Waveform API the code was completely portable between platforms The significance of this cannot be denied On the other hand there were some irritating differences between platform specific MFC objects such as CSocket and CCeSocket DirectShow on CE was a terrible problem and we spent months of time porting over sample code for network DirectShow filters In that time we could have used the lower level APIs to fully implement the functionality we needed and used the extra time for testing and implementing WAP selection into the RRS system This brings me to the biggest problem with Microsoft APIs There are hundreds of them and even though many of them claim to be for a certain task often times this object oriented approach just has too much overhead and isn t worth the time to develop with None of the Microsoft documentation will tell you that a certain task will take less time using one API over another unless you have help and supervision you ll be left trying to find the best tool for your job If you re like us the first few tools and months of work just won t cut it Of all the object oriented work we did we learned one thing you can t debug an object until you know how the lower level fu
99. r debugging threads or iterative algorithms that repeat many times 1 3 6 Helper Tools Two tools necessary for our Windows development with Visual C NET are the Error Lookup tool and the Registry editor The Error Lookup tool accessible from the Tools menu is used to correlate hex values with error messages When debugging an application many API calls will return zero if successful or one of potentially thousands of error messages if not In the debugger by copying the value from the variable watch tab into the Error Lookup tool you can check what that error value means For debugging DLL files it is necessary sometimes to check the registry to see if they were registered correctly with the operating system Each DLL has Globally Unique Identifiers and Class Identifiers in their source code that will find their way into the Windows Registry if they were registered properly Usually they show up under the HKEY CLASSES ROOT CLSID key 13 E 1 4 Remote Development Microsoft eMbedded C 4 0 eMbedded C 4 0 is the standard IDE for developing C applications for Windows CE platforms It would be nice if it shared all the same features as Visual Studio NET but in reality eMbedded C is a offshoot of the Visual C 6 0 line while Visual C NET is another name for Visual C 7 0 The two IDEs have very different interfaces and feature sets in particular because eMbedded C 4 0 has to worry about compiling programs for ea
100. r your application s window painting or display routines Even the visible windows themselves are described by class objects just like the filter graph If you build a dialog application as we did the window handle variable will be m_hWnd but if you created a different type of application your window handle may have a different name To find it type the name of your application class ours was CDialogappD14g followed by two colons and watch the auto completion come up with all the potential methods and variables for that class Chances are the variable containing hwnd in it will be the one you re looking for Unfortunately we re not even close to done making an event handler Our graph is set to send messages to our main application window but the main application doesn t know how to deal with these events The Windows way of handling messages is to set up the WindowProc function from one of your application classes such as CDialogappDlg WindowProc will handle any application level messages and send the rest of them to a lower level handling routine also named WindowProc but within a lower level class You must create this WindowProc using the Class Wizard selectable from the View menu or by pressing Ctrl W Double click WindowProc from the list of messages found in the Class Wizard window under class name CDialogappDlg replace with your application class name It will create an empty WindowProc function with the ap
101. rd 30 MB Free Hard Disk Space Extra Hard Disk Space for Archival of Sound Files Voice Recognition Program For using Voice Recognition capabilities Step by Step Installation 1 Place the Installation CD into the CD drive on your host computer In the dialog box that appears choose to install the Host Application 2 If the installation does not start automatically click Start Run Dihost setup exe where D is the location of your CD drive 3 Choose a location on your computer s hard drive for the program files After you have chosen a location click Next to continue installing the host application 4 Wait for the files to copy to your computer 5 Click Finish once the files are copied 6 Shut down your computer and begin installing the cradle according to the Quick Start Guide supplied with your Remote Unit 7 After the cradle is connected restart your computer 8 fit is not already in your computer s CD drive insert the Installation CD 9 In the dialog box that appears choose to install the ActiveSync remote software synchronization program Follow the on screen directions to install it When you are finished installing ActiveSync your host computer is ready to be configured for remote units Remote software Before Using the Remote Before using the remote be sure to charge the batteries for the remote for the amount of time specified by the Quick Start Guide supplied with your
102. recision of the sound buffer For our purposes we stored these values in global variables so that they could be reassigned in order capture and playback and any supported wave audio format WAVEFORMATEX wfx WAVE FORMAT PCM nChannels SampleRate BytesPerSec BlockSize SampleBits 0 Fig E 29 Setting up the Wave Format structure 5 Construct Buffer Description Structure The DirectSound Buffer Description structure is used in a similar way as the WaveFormat structure but also includes additional flags and settings because of the additional features available in a DirectSound buffer that a normal WaveFormat buffer does not have The Capture Buffer Description is slightly different than the Playback Buffer Description in the types of sound effects flags that can be added to the buffer Capture Buffer dscbd dwSize sizeof DSBUFFERDESC dscbd dwFlags DSBCAPS GLOBALFOCUS dscbd dwBufferBytes CAPBUFFERSIZE dscbd dwReserved 0 dscbhd lpwfxFormat amp wfx dscbd guid3DAlgorithm GUID NULL Playback Buffer dsbd dwSize sizeof DSCBUFFERDESC dsbd dwFlags 0 dsbd dwBufferBytes CAPBUFFERSIZE dsbd dwReserved 0 dsbd lpwfxFormat amp wfx dsbd dwFXCount 0 39 dsbd 1pDSCFXDesc NULL Fig E 30 DirectSound Buffer Description Structures 6 Create Sound Device The Direct
103. remote unit This may take up to 24 hours depending on the remote used for your system System Includes The remote system should come with the proper operating system and remote unit software preinstalled If it seems that the device does not have the proper software installed see the Troubleshooting section of this guide It is possible though unlikely that you will need to reinstall the remote unit software on the remote unit Step By Step Installation To install the software on the remote device first install the cradle onto the host computer as described in the Quick Start Guide for your remote unit The remote software is contained on the Installation CD Installing it on the remote involves simply copying the executable file from the CD onto the remote unit s flash memory then copying a shortcut to the device s startup folder Copying the Executable 1 Insert the Installation CD into your host computer s CD drive Close the dialog box that appears for host software installation Open the CD by double clicking on My Computer Right click on the icon for your CD drive and choose Open 2 Be sure the remote unit is properly connected to the cradle and that ActiveSync is connected to the remote unit so that it can synchronize Click the Explore button on the toolbar at the top of the ActiveSync window A file browser will appear that shows the files on your remote unit 5 In the file browser for your CD driv
104. ription The playback filter graph is stopped and an end stream command is sent to the host Host Function Host Ready Play Input none Occurs when a playback stream request is received from the SRU Output host ready play packet sent to SRU Description When the host receives a playback stream request from the SRU the host confirms to the SRU that the request was received Function Begin Stream Input audio file stored on host machine Occurs immediately following the Host Ready Play function Output audio stream to the SRU Description The host sets up and runs the playback filter graph which begins streaming audio from an audio file to the SRU Function Skip To File Input none Occurs when a skip to file request is received from the SRU Output none Description When the SRU sends a skip to file request the host stops playback of the current file opens the previous or next recorded file specified in the request and begins streaming that file to the SRU Function End Stream Input none Occurs when the SRU sends an end stream command Output none Description The playback filter graph is stopped and streaming of the current audio file is terminated IV MANUFACTURING A Product Lifecycle Plan 1 Introduction The Remote Recording System RRS utilizes three main technologies Windows CE DirectX and 802 11b wireless Internet Our solution incorporates all three technologies to creat
105. rs and microphones e Include volume controls for the recording and playback levels e Add voice command capabilities e Add headphone and microphone jacks for a headset e Add support for sound effects filters reverb Darth Vader etc 11 VIII APPENDICES USER S MANUAL SPECIFICATIONS ORGANIZATION OF CODE AND DOCUMENTS ON ACCOMPANYING CD BILL OF MATERIALS WINDOWS DEVELOPMENT AND API TUTORIALS TECHNICAL NOTES SHEETS BUILD INSTRUCTIONS REFERENCES 10 A USER S MANUAL Introduction Congratulations on purchasing the Remote Recording System This system is one the most advanced dictation system ever constructed The features have been designed for ease of use and mobility to make for responsiveness an easy to use interface and portability We hope you find the system powerful and useful About this guide This guide describes how to install and use the Remote Recording System The topics described herein include Host software installation Host setup Remote Management Application configuration Recording tracks for dictation Playback Skipping tracks Troubleshooting Installation Host Software System Requirements The host software has been tested for use on IBM compatible computers running Windows XP Professional Follow these recommendations for your system Pentium III or Athlon 750 MHz 256 MB RAM DirectX 9 0b Runtimes Wireless Network Interface Card Windows Compatible Sound Ca
106. rsions used on each platform and where they came from The above table shows the version of DirectX that corresponds with the OS on each hardware platform On the host end note that the DirectX 8 runtime DLL is installed with all versions of Windows XP but DirectX 9 is the newest version as of this writing For software development on the host a version of the DirectX SDK was required We decided to use the newer DirectX 9 SDK as it included DirectShow network sample code that was useful for us Newer versions of DirectX are backwards compatible with the older versions though and we were careful to use methods and objects common to both DirectX 8 and 9 runtimes so our application would be backwards compatible On the remote side DirectX is included with the various versions of the Windows CE SDK These versions lack some of the features of the desktop versions and are listed accordingly in the table 11 E 1 3 Host Development Microsoft Visual C NET Visual Studio NET is Microsoft s unified development environment for Windows software supporting a myriad of compilers and tools under a single Integrated Development Environment IDE Visual C NET is designed to work with object oriented program design and emphasizes looking at code not by files but by classes with its class selection menus and wizards It is the only reasonable way to develop using Windows APIs 1 3 1 Projects Solutions and Dependencies In Visual Studio NE
107. runtime lib AFXWinInit AFXWinInit 2 Construct a Socket CSocket sockSrvr CSocket sockClient 3 Create the Socket sockSrvr Create sockClient Create 4 Start Listening sockSrvr Listen 5 Seek a Connection sockClient Connect 6 Construct new socket CSocket sockRecv 7 Accept Connection sockSrvr Accept sockRecv 8 Construct file object CSocketFile CSocketFile file amp sockRecv file amp sockClient 9 Construct Archive CArchive ariIn amp file CArchive arOut amp file CArchive load CArchive store 10 Use the Archive to pass arin gt gt dwValue arOut lt lt dwValue data Table E 4 Steps to create and use AFX CSocket interface 1 Initialize the Runtime Library Call AFXWinnit passing the HINSTANCE of the current module and any command line parameters passed to the console app when the executable was called This can be done in an If statement with an error handler because AfxWinInit returns a FALSE if it fails if AfxWinInit GetModuleHandle NULL NULL GetCommandLine 0 _Eprintf T Fatal Error MFC initialization failed n nRetCode 1 r Fig E 19 Initializing Afx 34 2 Construct a Socket Call the constructor CSocket and specify the name you wish to give the socket object You can also construct CSocket pointers and use the new command to construct the socket CSocket m pSocket NULL m pSocket new CSocket Fig E 20 Constructing a new
108. s SRU Function Input Occurs Output Description Function Input Occurs Output Description Host_Connect Host IP Address Upon SRU power up SRU is linked to a host machine Attempt to connect to the host at the given IP Address over the network waiting for the listening host computer to respond The unit can begin normal operation once a host has been found Host Disconnect none On SRU Power Off command none Sends a Disconnect control signal over the network to the Host and powers down Host Function Input Occurs Output Description Function Input Occurs Output Description Wait for SRU SRU IP Address Any time a connection between host and SRU is not in place If the input packet is a host request from the SRU IP send ACK Waits for a host request packet from the specified SRU whose IP address is selected in the SRU Host Interface Terminal SRU_Power Off none when the SRU sends a power off command none Host software goes into a power off state where it waits for the SRU to reconnect 2 Recording Functions SRU Function Input Occurs Output Description Function Input Occurs Output Description Function Input Occurs Output Description Host Function Input Occurs Output Description Start_record none When the user presses the record button Stream creation functions Creates and sets up the record filter graph and
109. s The simplest option for mitigating the problem of hearing loss with headphones is to set a safe upper limit on headphone volume Many portable music devices employ an AVLS or Automatic Volume Limiting System technology to protect the listener s hearing We could try to develop some method of AVES in hardware or simply set a reasonable limit on the volume dial to which the user will have access B Environmental Issues Two environmental factors are involved in the use of this device speaker volume and radio interference The external speaker should be limited to a reasonable volume that won t disrupt a moderately loud conversation Interference is another important consideration the interference this device causes is discussed in relation to FCC rules in the Regulatory Issues subsection The remote unit is also subject to environmental interference Although the orientation of the internal antenna is primarily responsible for how well signals are received factors such as weather interference walls and other physical obstructions degrade wireless performance Furthermore there is the issue of disposing or reusing components of the device Lithium lon batteries can be recharged or recycled and are safer to dispose of than other common battery types such as Nickel Cadmium Services exist to recycle and refurbish entire cell phones and PDAs as well 5 C Legal Issues Since we developed our project using academically licensed s
110. s card is properly installed and configured Host s Remote Management Application not running Start the Remote Management Application and ensure it is in the Startup folder in Programs on the Start menu Remote is not configured to communicate with Host Use the Host s Remote Management Application to add your Remote to the list of known Remotes B SPECIFICATIONS 1 Audio Characteristics a Sample rate 44100 Hz b Bits per sample 16 c Number of Channels 1 monaural d Compression MPEG Layer 1 audio compression Hardware Specifications a Internal Microphone i Sensitivity 65dB 0dB 1V 0 1Pa Y 1kHz ii Frequency Response 100Hz 15kHz b Internal Speaker i Sensitivity 88dB 1 W ii Frequency Response 600Hz 10kHz 10dB Remote Device Specifications a Processor Intel XScale ARM Processor b Operating System Microsoft Windows CE NET Version 4 2 c Device Size 7 5 2 d Weight 2lbs e Battery Life 3 hrs active use 12 hrs standby use f Battery 4 3V Li Ion Network Specifications a Wireless Protocol 802 11b b Frequency Band 2 401 2 473GHz c Reception Distance 100ft d Network Buffering Time 5s Host PC Operating System Windows NT Variant XP 2000 or newer C ORGANIZATION OF CODE AND DOCUMENTS ON ACCOMPANYING CD The disc is divided into a tree to separate documents code for the remote device and code for the host
111. s will rSec 44100 Ly EX structure as global variables The nOpen with the WAVE FORMAT QUI sInputFormatSupported function is simply a ERY argument which checks to see always be twice the sample rate UINT Byt UINT Samp BlockSize eBits 1 65 MMRES DWORD RetVa 1f Re MMRES VAVEFORMATI ULT RetVal dwBuffLength JAVE _ nChannels SampleRate BlockSize SampleBits 0 2 EX w x FORMAT PCM 0 r BytesPersec r Ts tVal Error h l nputFormat MMSYSERR andlin ULT Is re nputFormat VAVE FORMATEX pwfx 8192 NO g ERROR tSuppor UINT u turn wavel In0pen NULL uDevicel E pwfx NULL NULI uy WAVE FORMAT QUI ted Devicel D tSupported amp wfx ERY was 6000 WAVE MAPPER fe ptr can be The devic NULL for query identifier Defines th format No callback No instance Query only requested data do not open Fig E 39 Checking to see if the wave format is supported by the audio device 3 Open the Audio I O device For a playback routine the wave nStart that tells the microphone or line input to start recording sound is unnecessary The buffer allocation step is
112. scanf 54 Instantiating The Filter Graph Justin Cassidy Revision 3 Introduction DirectShow uses a Filter Graph paradigm i e connect the decode filter to the playback filter to play an encoded media file This document describes how to build the filter graph in a Windows CE application the problems we faced and the corrective measures we took to solve them It is written towards a group which is inexperienced in both DirectX and Windows programming Nomenclature Microsoft s sample programs use naming conventions that are sensible in a way Their protected pointers are named m_pGB m_pCapture etc and these point to memory locations for the graph builder the capture filter graph etc m stands for memory while p probably stands for protected Generally when a Windows function is called to create something or do an event the function returns type HRESULT This is an internally defined 32 bit value which Microsoft has defined constants for such as the values E NOINTERFACE and NOERROR You can easily trace their definitions back to windows h in the Microsoft IDEs by right clicking gt Go To Definition So when this document mulls over code like the following used to instantiate a DirectShow filter graph we can analyze it Get used to arguments that are reserved or meaningless to most programmers such as that second NULL in the CoCreateInstance hr CoCreateInstance CLSID FilterGraph NULL CLSCTX INPROC IID
113. sends a record command to the host and waits for acknowledge from host Begin stream Audio captured from microphone After Start Record when acknowledge is received from host audio data streamed out of network device Runs the record filter graph which begins the audio capture encode and network stream process End stream none When the user presses stop or record stop stream command to the host The filter graph is stopped and a stop stream command is sent to the host Host ready none When the host PC has connected to the SRU on the network acknowledges signal to the SRU that the host is ready Sends a packet to the SRU over the network that tells the SRU that the host connected and ready to function Function Input Occurs Output Description Function Input Occurs Output Description Begin Record record command from SRU While the stream is being transmitted from the SRU Acknowledge message to SRU The host sets up the record filter graph sends an acknowledge message to the SRU and then runs the filter graph to begin receiving the audio stream and decoding it to the virtual sound device input End Record none stop stream command received from SRU none The record filter graph is stopped 3 Playback Functions SRU Function Input Occurs Output Description Function Input Occurs Output Description Function Input Occurs Output Description
114. t of a build we fully document it for educational purposes and to supply a complete list of instructions and good documentation at the end of our project 2 3 Software Technology Costs Since we are students we were able to acquire Windows CE software and development tools from the University of Idaho Computer Science department at no cost However this means we are using educationally licensed tools to build this solution At some point near the end of the project we will need to purchase licenses from Microsoft to make the solution we have built available for full use and for retail sale 2 4 Networking The 802 11b wireless standard we are using is supported by the handheld unit we are targeting for our solution Our solution does not directly use Wi Fi networking but it asks Windows to handle the transfer of network data in that manner In the future then if the standard changes for Wi Fi networking our solution will still be able to ask Windows to handle the networking in the that manner The only changes will be to the Windows CE image we will have to build a new image that will support the new standards and include all the libraries we need for DirectX to function 3 Implementation And Testing Although this is a Computer Engineering Senior Design project the software nature of the design dictates that most of the testing we will do relates to software To this end our testing and implementation methodology exists not
115. te Fig 1 Remote Application Interface This image is what the interface looks like for the remote application which runs and the handheld device For our implementation the buttons will be on the screen and the user can use the pen to tap the buttons and control playback recording and track skipping Host Interface w SRU Host Interface Terminal Speech Recognition Unit Status r Select SAU SRU Name SRU NAME y Add Delete MAC 01 23 45 67 894B IP 128 2 0 1 Pi Settings Network Interface y Audio Device Test se Livel Wave Device y Audio File Location CATEMPY z Bm ES Fig 2 Host s Remote Unit Management Application This is what the host s SRU management application looks like There are fields for the nickname for a device the remote s MAC and IP addresses and the settings for the host s network and sound card The SRU Host Interface Terminal allows the user to add SRUs of any name of choice and the corresponding network address information for that SRU The user chooses which SRU to listen for on the network by selecting it from the SRU Name pulldown menu The user can also select which network interface adapter the program will use to communicate to the SRU and which sound device to send the decoded audio stream to HI FUNCTIONAL SPECIFICATION A Functional Overview The functionalities of the RRS system fall into three categories control r
116. ted For debugging make sure your program has the chance to call wave InClose after it opens the audio device for I O If you fail to do so you might not be able to open the device later because it is still in use On the PDA this would require a soft reset to fix 48 E 2 7 Benefits and Disadvantages of Windows Programming After discussing no less than six different Windows APIs you might be curious about the overall strengths and shortcomings of the Windows way of programming software Even after months of reading through Microsoft documentation and becoming more proficient in C and strange data types we still aren t experts in Windows programming Still we ve seen the ropes and also have special insight on porting between different versions of Windows So let s take a look at the good and the bad of Windows programming 2 7 1 Programming Environments With cross platform Windows development the biggest strengths and weaknesses lie with the development tools The ability to debug your code step by step is crucial when developing GUI interfaces where it is impossible to use debugging output statements like printf With adjustable breakpoints and quick searching for variable and function definitions it is the best debugging utility we have ever used On the flipside the Visual Studio NET project format is not compatible with the eMbedded C project format This caused hours of copying files from one directory to anothe
117. tes how they might be used to receive data from the network and write it to a file CFile myFile NULL CSocket m pConnectedSocket NULL CArchive m pArchiveln NULL void pvAudioPtrl NULL UINT iTemp 0 m pConnectedSocket new CSocket Create the socket as a sender or receiver with your own routine HERE m pFile new CSocketFile m pConnectedSocket m pArchiveIn new CArchive m pFile CArchive load Receive with this home made function iTemp NetSendReceive m pArchiveIn pvAudioPtrl dwAudioBytesl Write void wave memory to a file myFile Write pvAudioPtrl iTemp Fig E 43 Receiving data over a socket with MFC objects The example above initializes all the objects needed to create a MFC socket object a MFC file object and the helpers needed to send buffers over a network interface Information on creating connected or listening CSocket objects is discussed in the MFC documentation in section E 2 4 Notice that our NetSendReceive can look at the socket mode and figure out whether to send or receive data using the same Read and Write method as the CFi le object does UINT NetSendRecieve CArchive amp m pArData void Data UINT nMax if m pArData IsStoring send mode m pArData Write Data nMax m pArData Flush return 1 else receive mode 47 return m pArData Read Data nMax Fig E 44 Network data transfer code that checks the state
118. the filter memory properly and set up all the component pins 2 2 4 CLSIDs GUIDs and the Windows Registry When building a DirectShow filter for use in other applications one aims to create a DLL file loaded by Windows that other applications can use When Windows loads the DLL file that a project builds remember to check the Register DLL option in your Build properties it creates a new Class Identifier CLSID in the Windows Registry The Windows Registry is a huge table of values useable by any program the OS is running and the only way to read or write to it outside of the regsvr32 application is with the regedit tool So when a DLL is registered with the operating system the CLSID is stored in under the HKEY CLASSES ROOT CLSID key in regedit The CLSID is a specific type of Globally Unique Identifier GUID used by objects that are activated at run time Under the GUID key it might give the object name and other properties but it always lists in what DLL the object is found So when the main program wants to use that filter object it instantiates it using the CoCreateInstance function malloc for class objects with the CLSID of that object as one of its arguments static const GUID CLSID DSNetReceive 0x319f0815 Oxacef Ox45fe Oxb4 0x97 Oxa2 Oxe5 Oxd9 Oxa 0x69 Oxd7 CoInitialize NULL CoCreateInstance CLSID DSNetReceive NULL CLSCTX INPROC SERVER D IBaseFilter void amp g pSend
119. thod will be created that can be lovingly coded Topics Related to Keypad Input Accelerators Windows Resource for Assigning Keystrokes to Actions Since the final HW will have no screen so all actions should be accessible with single keystrokes Accelerators are keystrokes that accomplish tasks defined in the user interface IBC BUTTONI seems to define a single button click to Button1 and a key can be mapped to do that same action Two types of keys can be assigned ASCII keys and VirtKeys VirtKeys is the naming system used internally by Windows CE When you add a button and right click it for its properties press the Use next key pressed button to press a key and assign the proper VK This doesn t seem to work when I test using breakpoints although clicking on the buttons with the mouse in the emulator works So we ll avoid accelerators for now 52 Accelerator Alternatives Using a button with a name of amp Play or Pl amp ay makes the P and a keys activate those buttons respectively and this is a working alternative to accelerators i The PPT Keypad On the PPT 8846 a key editor called Keyboard Properties will let you change the unit s buttons to correspond to different keyboard keys Scroll Up Down Keys Application Application Keys y Keys Function Key Power Button Enter Button The default layout for the keys is as follows PDA Keypad Keyboard S
120. tiating the Filter Graph Making ActiveSync Work Creating A MFC Console Application Project Platform Builder Windows CE OS Images and Platform SDKs Configuring a Wireless Network Between a Host and a PDA Our technical notes describe in detail important steps we took to set up a working environment between a PC and a PDA These notes may not be necessary for you in setting up a build environment to duplicate our own results but they will certainly save you time if you do read them They are written from a practical step by step perspective as we were figuring out how to make our project work For those with the same amount of background experience and education as we have these notes should prove useful Justin Cassidy 5 04 2004 50 Technical Notes An Example Justin Cassidy Revision O Introduction Over the course of our Senior Design project we ll be working with a number of technologies that we ve never studied before elsewhere The purpose of a short technical note paper such as this is to compile the work and research you ve done on a topic into a recipe like form that is easy to refer to after the fact I envision our final documentation will have a section devoted to categorically organized technical note sheets The goal of these papers is not to be a writing exercise it is to put the information you are using and are likely to forget or need to look up later into a easily referenced source that is easy to send to others I
121. tion wraps to the beginning of the buffer 40 For instance in a 1000 byte buffer if I call Lock with an offset of 800 and a size of 300 bytes the first pointer would point to the location of byte 800 and number of bytes would be 200 and the second pointer would point to zero the beginning of the buffer and the number of bytes in that portion would be 100 Special care should be taken to not lock a portion of the buffer that is currently being played or captured to by the sound device One way to check for this condition is to poll the position of the playback or capture pointer using the GetCurrentPosition member of the DirectSound Buffer hr pDSB gt Lock dwBeginRead PACKETSIZE amp pvAudioPtrl amp dwAudioBytesl pvAudioPtr2 amp dwAudioBytes2 0 Fig E 35 Locking a portion of the DirectSound Buffer 11 Copy Buffer Data Once a section of the DirectSound buffer is locked audio data can be written to the locked memory block for playback or copied from the block after being captured for the application to use This can be done with a simple memcopy command into an array in memory or in the case of this project the lock pointers and number of bytes can be passed to the Read or Write members of a CArchive object to send that audio data out of the socket or read audio data in from the socket and store it to the DirectSound Buffer m pArchiveOut Write pvAudioPtr1 dwAudioBytesl if dwAudioBytes
122. tructing a CSocketFile object and connecting it to the CSocket 9 Construct Archive The CArchive object is used as the interface for sending or receiving data to the CSocketFile If one way communication over the socket is all that is necessary then only one CArchive needs to be created passing the CSocketFile and the type of CArchive load or store as parameters If two way communication over the socket is necessary then two CArchives must be created one for storing and the other for loading CArchive m pArchiveln NULL CArchive m pArchiveOut NULL m pArchiveln new CArchive m pFile CArchive load m pArchiveOut new CArchive m pFile CArchive store Fig E 25 Constructing a CSocketFile object and connecting it to the CSocket 10 Use the Archive to pass data The CArchive objects can now be used for sending or receiving data over the Socket connection Data transmitting and receiving can happen asynchronously between client and host The CArchive accept or receive data through the overloaded lt lt or gt gt operator much like cin and cout are used Or for larger chunks of data the write and read operators can be used which accept a pointer to the address of the data to be sent and the number of 36 bytes to be sent The read operator returns an integer value of the actual number of bytes read This is useful if the end of the buffer was reached before the requested nu
123. uidaho edu where the host is located or perhaps even use the system in an entirely faraway place so long as the remote and host can communicate with each other over the wireless network C Problem Solution In solving this problem we forged our way through several different methods and Programming Interfaces before finally settling on the Windows Waveform API Initially we had thought it would do us all a favor to use a simply interface for programming such as DirectX Microsoft made the DirectX suite of APIs so that programmers could have access to the speed and power of hardware without worrying about manipulating the hardware on their own As a result games Internet programs and other multimedia rich applications use generic calls to DirectX libraries After several months of developing for the handheld unit our sponsor asked us to use we discovered that the libraries we were using were not installed on the handheld and there was no way for us to put those libraries on the handheld device a critical step in launching our application While our code worked very nicely on desktop computers we were unable to make it run on the handheld device At this point we looked to something much simpler The Waveform API is a low level interface that is purportedly the lowest level of programming available that will easily accommodate audio data transmission With some generic buffering for data collection a touch of Windows Sockets pr
124. utside of the actual handheld Although the Windows CE Emulator has been mentioned before it is for all intents and purposes its own Windows CE Platform It runs approximately 80 speed compared to a real device and has no wireless Ethernet drivers However it accepts socket connections has 802 3 Ethernet functionality and it loads and debugs compiled code exactly like a real physical platform Its major disadvantage outside of not being a real device is that building for real platforms requires additional setup work due to building and including different libraries for different architectures and setting up linker input lists for each architecture can be a chore In particular if the linker directories list is in the wrong order you might not build with the right libraries for your architecture 16 E 2 WINDOWS API DOCUMENTATION E 2 1 Introduction The Windows Application Programming Interfaces APIs used in the Remote Recording System RRS are just a few out of the many hundreds Microsoft has developed to make Windows development and deployment happen faster and sometimes easier Although many Windows APIs support languages such as Visual Basic and the new NET runtime framework all of the primary Windows APIs are designed with C object oriented development in mind This sections provides an overview of functions and class objects for each of the APIs we worked with during the duration of our project These are designed to supplement t
125. veInOpen waveOutOpen wavelnStart 4 Allocate and Prepare buffers wavelnPrepareHeader wave0utPrepareHeader 5 Send or receive audio data waveInAddBuffer waveOutWrite using the buffer 6 Un prepare a buffer waveInUnprepareHeader waveOutUnprepareHeader 7 Read or write buffer to froma CFile Write or CFile Read or file or a socket interface CArchive Write CArchive Read 8 Close the Audio I O device waveInStop waveOutStop wavelnClose waveOutClose Described together as part of a buffering loop Our own functions full source provided Table E 6 Audio Recording and Playback using the Waveform API Not only do the names of the corresponding record and playback functions look similar they have the exact same arguments In fact by changing the variable type names i e HWAVEIN to HWAVEOUT and function names i e waveInAddBuffer to waveOutWrite in the record routine snippets shown in the following steps you ll have a playback routine as well 1 Check if Audio I O devices exist if waveInGetNumDevs lt 1 Are there audio input devices Error 42 2 Select a Wave Format The tricky part here is setting up the structure correctly In our program we store the parameters for the WAVEFORMATI wrapper to the special case of wave 1 if the device will support the given format UINT UINT UINT Sampl For 16 bit sP nChannels eRate 22050 audio thi
126. w Locus profile 62 Remarks Without a key you may create a profile that doesn t find the correct unprotected wireless connection So make sure you set up a key with your profile Also the profile on remote and host ends must have the same name or they won t know to talk to each other DO NOT BRIDGE YOUR WIRELESS CARD TO OTHER CONNECTIONS or you will pay a huge performance penalty on your wireless network We re talking 2kB sec transfers versus 20kB s transfers To avoid using a bridge you can disable other network cards on your computer or set the wireless card as the preferred device in the settings for Windows Networking See your computer s documentation for more details about preferred network devices 63 G REFERENCES 1 Microsoft End Of Life Support Cycle Visited 02 25 04 Avail 2 3 4 5 http support microsoft com default aspx scid fh In LifeEmbedded 6 NCH Tone Generator Visited 4 13 04 Avail http www afreego com Categories Multimedia Audio and Sound Tools 016646 php 64 65
127. with the Linker input list and start including exact pathnames to each and every library file note that Visual C NET has directory lists it searches when it looks for everything from include files to libraries and binaries Go to the Tools menu click Options and click the Directories tab Sometimes library errors arise because the library search directories aren t in the correct order and you re obtaining the wrong version of a particular library To reiterate Windows libraries in four steps Include the proper header files Find where the libraries you need are located and add those paths to the directory list Add the required static libraries to the Linker input list Make sure DLLs are registered 1 3 5 Step Through Debugging The real strength of any Microsoft IDE is its debugger which allows the developer to step through the code line by line as it is executing In addition there are tabs for watching local and user specified variables as the program is running eliminating the need for numerous printf or cout debugging statements Breakpoints are used to halt execution at specific points F9 after which execution can be continued F5 or code can be stepped through one line at a time F10 F11 will step into the currently highlighted function Breakpoints may halt execution if a variable has a specific value or alternatively every n times it is reached Right click a breakpoint to set its options This is extremely useful fo

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