Branching Playback Library User`s Manual
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1. Execute the Branching Playback Server Execute the stream server Execute the server function of Branching playback complete status Destination selection wait state 1 button B negative no input Select a destination Destination determined state No destination state Decoding completion check 15 chgsw ON Branch execution switch on ret BPL_GetNextStm KEY_MAX stmtbl Get a destination stream if ret gt 0 If there is a destination destoroyDecodeHn dc_hn Clear the decoder handle dc hn createDecodeHn stmtbl Create a decoder handle break destoroyDecodeHn dc_hn Clear the decoder handle The BPL automatically opens and closes a stream by using the Stream System Fora description of the decoder refer to the applicable library manuals i SEGA 6 Data Specifications 6 1 Basic Data Title Data Data Name No Data specifications Basic data 1 0 1 Basic Data pes Descripton Unsigned 1 byte integer Signed 1 byte integer Unsigned 2 byte integer Sint16 Signed 2 byte integer Uint32 Unsigned 4 byte integer Sint32 Signed 4 byte integer Boolean 4 byte integer logical constants are used as Boolean 2 Logical Constants Logical constants are used as Boolean values Description FALSE 0 Represents the FALSE logical value 0 Represents the switch off FALSE state 1 Represents the switch2. Stream System STM CD Communication Interface CDC Software Hardware SIMM SPINE SCSI File Figure 1 1 Organization of CD related libraries The Branching Playback Library requires each of the following libraries Stream Sys tem File System and CD Communication Interface S EGA 1 2 Summary of Branching Playback Library Functions 1 Setting the Branch Destination Scenario Information This function sets destination stream candidates as destination scenario information 2 Pre reading the Streams Necessary for Branching The BPL manages the opening closing of streams to smoothly branch between streams By pre reading an open stream a branching destination stream candidate into the CD buffer the stream can be fetched without interruption when the branch destination is determined 3 Destination Selection Function The BPL selects the actual destination from the destination candidates 4 Destination Stream Notification Function Based on the selected destination the BPL notifies the application of the next stream to be played Set initialization and destination information Select a Application destination gt Stream handle STM_Open STM_Close Create EntryNext Stream System Decoder Cinepak MPEG etc Figure 1 2 Stream system overview diagram Branching Playback Library User s Manual 2 Basic Items 2 1 Definitions Table 2 1 Terminology Mea
3. When the branch execution switch is ON performs branching switches branch streams 1 Branching playback state Description BPL SVR COMPLETED Branching playback completed Wait for the selection of a destination Destination selected BPL SVR NOBRN No destinations For branching playback states see Section 3 3 Changing Branching Playback States Title Data Data Name Function Select destination BPL SelectBranch specifications Format Sint32 BPL SelectBranch Sint32 brno Input brno Branch number Output None Function value Error code Function Selects a destination according to a specified branch number Remarks a Specifying the switch ON during the execution of the BPL ExecServer function results in branching the current stream is switched with the selected destination b A destination must be selected even when there is only one branch candi date 2 SEGA Title Data Data Name Function Get current stream BPL_GetCurStm specifications Format Sint32 BPL GetCurStm Sint32 nelem StmHn stmtbl Input nelem Number of elements in the stream handle table nelem XBPL STMKEY MAX Output stmtbl Stream handle table Function value Branch stream ID Negative ID no corresponding branch streams Function Gets the current stream branch stream ID and the stream handle that is subject to read access Remarks a Stream handles that correspond to str
4. BP state transition diagram Branching Playback Library User s Manual 3 4 Executing Branching Branch Stream Switching 1 Executing branching When branching is performed in the destination selected state by turning on the branch execution switch of the Branching Playback Server branch streams are switched as follows a The current stream A is closed The BPL stops reading A and deletes any data that remains in the CD buffer b The destination stream B becomes the current stream c The destination stream becomes undefined Table 3 2 Switching branch streams by executing branching Branch Stream Before After Branching after switching Branching Current stream obtained by the A B BPL_GetCurStm function A is closed Destination stream obtained by Undefined until the next destination is the BPL_GetNextStm function selected and determined by the BPL_SelectBranch function The selection of a destination always precedes the execution of branching switching However the selection and switching operations are generally performed asynchronously 2 Opening and closing a stream The BPL opens both the current stream and branch candidate streams The BPL employs the following opening and closing procedures a Starting playback stream specified by the BPL_Set Start function is opened first as the current stream b When the reading of the current stream begins branch candidate streams are opened c When a
5. be opened simultaneously specified using the STM Init function Title Data Data Name Function Get destination information BPL GetBranchInfo specifications Format Sint32 BPL GetBranchInfo Sint32 bstmid Sint32 nbranch Sint32 brtbl Sint32 nelem Input bstmid Branch stream ID nelem Number of branch table elements Output nbranch Number of destinations 0 if no branch candidates brtbl Branch table a maximum of nelem branch candidates are stored from the beginning of the table Function value Error code Function Gets the destination information that is assigned to a branch stream Branching Playback Library User s Manual 21 7 2 Branching Playback Processing Title Data Data Name Function Set playback start stream BPL_SetStart specifications Format Sint32 BPL_SetStart Sint32 bstmid Input bstmid Branch stream ID BPL_BR_NONE stops branching playback Output None Function value Error code Function Specify a playback start stream the branch stream at the beginning of a scenario To stop branching playback specify BPL_BR_NONE as the branch stream ID Title Data Data Name Function Execute Branching Playback BPL_ExecServer specifications Server Format Sint32 BPL_ExecServer Bool chgsw Input chgsw Branch execution switch ON branch OFF do not branch Output None Function value Branching playback status Function Executes the Branching Playback Server
6. destination is selected all other branch candidates are closed and only the destina tion is pre read d When branching is executed the current stream is closed The destination stream becomes the current stream and steps b d are repeated e When branching playback is completed the stream group is closed 3 Timing for branch stream switching Table 3 3 shows the timing types for branch stream switching Table 3 3 Timing for branch stream switching Natural Switches to destination stream B upon completion of decoding switching stream A Forced switching Force switch to destination stream B regardless of whether stream A is being decoded Branching must not be executed until the decoder finishes processing the current stream even when a destination is determined to prevent truncation of the stream data that is being decoded Regardless of whether normal or forced switching is performed switching processes for the decoder should be executed first The branch execution switch should be turned on only after switching is complete r SEGA 4 Organization of Files on Disc The total amount of streams that can be pre read is limited by the capacity of the CD buffer a maximum of 200 sectors Therefore streams that exceed the limit and can not be pre read may result in branching delays 1 Non interleaved branch candidates Suppose that A s branch candidates are B and C and that files are positioned on disc as shown
7. in Figure 4 1 Then only file B can be pre read There will be no problems if the pre read data of A is sufficient to seek branch to B or C However if both B and C need to be pre read in order to enable delayed branch selection timing branching to C in this example cannot be performed without delay Stream branching Position of files on disk A B A B C C c RR gt 200 or more sectors Figure 4 1 Non interleaved candidate branches C cannot be pre read 2 Interleaved branch candidates As shown in Figure 4 2 one method of enabling branches to B and C without delay after A is played is to interleave B and C immediately after A Stream branching Organization of files on disk A B b1 b2 b3 A b1 C c14c2 c3 B and C are interleaved c1 b2 c2 b3 are Note Two branch candidate files exist B and C Figure 4 2 Interleaved branch candidates all of B and C 3 Partially interleaved branch candidates As shown in Figure 4 3 it is also possible to split B into B1 and B2 and C into C1 and C2 and to interleave only B1 and C1 Branching Playback Library User s Manual 11 12 In this case it is sufficient to interleave only parts of B and C B1 and C1 This technique allows a seek to B2 and C2 and enables highly independent operation However the technique requires the division of files Stream branching Position of files on disk A B1 B2 A le
8. 1 The application fetches the branch stream that is currently being read and sets it in the decoder After reading bstm1 the BPL begins reading branch candidates branch streams that may be fetched next bstm2 bstm3 bstm4 and bstm5 Effective use of the CD buffer and smoother branching is made possible by pre reading branch candidate streams The application fetches events such as input from a control pad and selects the destination for branching If branch numbers 0 3 are assigned to branches bstm2 bstm3 bstm4 and bstm5 and if 1 is specified reading of bstm2 bstm4 and bstm5 which is no longer needed is canceled If necessary the application fetches the destination stream and sets it in the decoder After fetching bstm1 the BPL begins fetching bstm3 If the application specifies the execution of branching to the Branch Play Server the BPL begins reading bstm9 bstm10 and bstm11 as in c SEGA 3 3 Changing Branching Playback States Table 3 1 shows branching playback states Figure 3 1 shows a branching playback state transition diagram Table 3 1 Branching playback states End of branching Branching playback ended playback The stream group and the streams that were opened by the BPL the current stream and candidate streams are all closed Wait for a Branch candidates were pre read but a destination has not destination been selected selection All streams among the branch candidates are subject to pre re
9. C1 B2 C2 C1 C2 B1 and C1 are interleaved Note Four branch candidate files exist B1 B2 C1 and C2 Figure 4 3 Partially interleaved branch candidates parts of B and C SEGA 5 Basic Examples 5 1 Scenario Processing Figure 5 1 shows an example of a branching playback scenario Branch number ButtonA 0 BSTM2 MPG BSTM1 MPG ButtonB 1 BSTM3 MPG Button A is pressed while BSTM1 MPG is being played 5 BSTM2 MPG is played after BSTM1 MPG Button B is pressed while BSTM1 MPG is being played BSTM3 MPG is played after BSTM1 MPG Figure 5 1 Example of a branching playback scenario The following is a sample program that sets this scenario define BSTM MAX 3 Total number of branch streams BSTM1 MPG BSTM2 MPG BSTM3 MPG define BRANCH MAX 2 Total number of branches number of arrows in Figure 5 1 Total number of stream key types Branch number assigned to button A Branch number assigned to button B Number of branches per stream Branch stream ID of BSTM1 MPG Branch stream ID of BSTM2 MPG Branch stream ID of BSTM3 MPG define KEY MAX define A BTN define B BTN define BR NUM define BSTM1 ID define BSTM2 ID define BSTM3 ID NOrRPONF ON Work area for the BPL Sint32 work bpl BPL WORK SIZE BSTM MAX BRANCH MAX KEY MAX sizeof Sint32 void setScenario void StmKey key KEY MAX Area
10. General Notice When using this document keep the following in mind Te This document is confidential By accepting this document you acknowledge that you are bound by the terms set forth in the nondisclosure and confidentiality agreement signed separately and in the possession of SEGA If you have not signed such a nondisclosure agreement please contact SEGA immediately and return this document to SEGA This document may include technical inaccuracies or typographical errors Changes are periodi cally made to the information herein these changes will be incorporated in new versions of the document SEGA may make improvements and or changes in the product s and or the program s described in this document at any time No one is permitted to reproduce or duplicate in any form the whole or part of this document without SEGA s written permission Request for copies of this document and for technical information about SEGA products must be made to your authorized SEGA Technical Services representative No license is granted by implication or otherwise under any patents copyrights trademarks or other intellectual property rights of SEGA Enterprises Ltd SEGA of America Inc or any third party Software circuitry and other examples described herein are meant merely to indicate the character istics and performance of SEGA s products SEGA assumes no responsibility for any intellectual property claims or other problems that may resul
11. Interface CD cd Cd These symbols must not be used by the application program SEGA 3 How the BPLWorks 3 1 Flow of Processing The BPL reads a stream according to a given scenario and notifies the application of the stream handle that must be decoded Figure 3 1 shows the flow of main processing events Initialization BPL_Init lt Specifies a work area A p Sets branch stream infor p Bae eeanata mation and destination information l BPL SetStmInfo C BPL SetBranchInfo a t Selects a destination gt BPL_SelectBranch BPL server execution BPL ExecServer Fetches a branch stream gt BPL GetCurStm BPL GetNextStm Figure 3 1 Flow of processing Branching Playback Library User s Manual 3 2 Scenario A scenario is information that indicates how branching playback is to be performed as a function of time the order in which streams are to be played Branched streams are specified in file units Audio and video data can be fetched by channel interleaving within a file bstml a b c d e Branch Number 0 bstm6 bstm16 R bstm7 ema A bstml7 bstm19 1 bst bstm3 bstm10 bstmll bstm12 bstm4 bstm13 bstml14 Are gt bstm15 Figure 3 2 Stream branching This scenario specifies bstm1 as the branch stream to be read first The BPL then starts reading bstm
12. ading Only the current stream can be accessed Destination streams cannot be accessed Determine A destination was selected from the branch candidates destination Only the selected destination is pre read Both the current stream and the destination stream can be accessed No destination There are no branch candidates or destinations for the current stream The last stream is being played The server function can get the branching playback status Initialize branching layback PY Reset branching BPL Init function BPL_Reset function playback Stop branching ON OFF Branching playback BPL SetStart function playback BPL SetStart function L gt complete BPL SVR COMPLETED specifies BPL BR NONE Executable in all states Ps OFF Wait for the selection gt No destination BPL_SVR_WAITSEL No candidates BPL_SVR_NOBRN BPL SelBranch function ON ON OFF OFFS Destination selected BPL SVR SELECT The selected destination was BPL BR NONE See the BPL_SetBranchInfo function Branch execution switch for the Branching Playback Server function BPL_ExecServer If ON is specified in a destination selection wait or no destination state then branching playback is terminated If ON is specified in the selected selected state then branch streams are changed Figure 3 3
13. chInfo Sint32 bstmid Sint32 nbranch Sint32 brtbl Input bstmid Branch stream ID nbranch Number of destinations brtbl Branch table Output None Function value Error code Function Assigns destination information candidate destinations to a branch stream Remarks a Assigns the branch stream IDs of branch candidates to the branch table To indicate that there are no destinations specify BPL BR NONE as a branch table element brtbl 0 BSTMID A brtbl 1 BPL BR NONE No destinations the end of BP brtbl 2 BSTMID_B nbranch 3 A destination is specified using the BPL_SelectBranch function and a branch number a position in the branch table In this example the branch processing produces the following results depending on the destination that is selected Selected Branch Processing Destination when the branch execution switch of the server function is on Branch number 0 Branches to branch stream ID BSTMID A Branch number 1 Terminates the branching playback process goes into the no destination state immediately after this branch number is selected Branch number 2 Branches to branch stream ID BSTMID B Other BPL SelectBranch returns the BP ERR BRNO error and invalidates the selection b The number of streams must satisfy the following conditions X YSZ X The number of stream keys that are set in bstmid Y Total number of destination stream keys Z Maximum number of streams that can
14. eam keys are set in the stream handle table Title Data Data Name Function Get destination stream BPL GetNextStm specifications Format Sint32 BPL GetNextStm Sint32 nelem StmHn stmtbl Input nelem Number of elements in the stream handle table nelem XBPL STMKEY MAX Output stmtbl Stream handle table Function value Branch stream ID Negative ID no corresponding branch streams Function Gets a destination stream branch stream ID and the stream handle Remarks a Stream handles that correspond to stream keys are set in the stream handle table b The function value remains negative until a destination is selected until the BPL_SelectBranch function is executed Title Data Data Name Function Get stream group BPL GetStmGrp specifications Format StmGrpHn BPL GetStmGrp void Input None Output None Function value Stream group handle Function Gets the handle of the stream group that is used by the BPL Remarks a When activated the BPL opens one stream group When the branching playback process is terminated the stream group handle becomes NULL Branching Playback Library User s Manual 23
15. for setting a stream key Sint32 Hbrtbl BR NUM Area for setting a destination Sint32 fid File ID Initialization of branching playback BPL Init BSTM MAX BRANCH MAX KEY MAX work bpl Setting branch stream information STM KEY CN key 0 STM KEY CIMSK key 0 STM KEY NONE STM KEY CN key 1 STM KEY CIMSK key 1 STM KEY NONE STM KEY SMMSK key 0 STM KEY SMVAL key 0 STM SM VIDEO STM KEY SMMSK key 1 STM KEY SMVAL key 1 STM SM AUDIO fid GFS NameToId BSTM1 MPG BPL SetStmInfo BSTMl ID fid KEY MAX key fid GFS NameToId BSTM2 MPG Branching Playback Library User s Manual 13 14 BPL Setstm fid GFS NameTold BSTM3 MPG Info BSTM2 ID fid KEY MAX BPL SetStmInfo BSTM3 ID fid K Set des brtbl A BT brtbl B BT BPL SetBra N BSTM2 ID N BSTM3 ID EY MAX tination information key key nchInfo BSTM1 ID BR NUM brtbl Branch to BSTM2 MPG if button A is pressed Branch to BSTM3 MPG if button B is pressed Set the destination for BSTM1 MPG 5 2 Branching Playback Processing The following is an example of a branching playback program Refer to Section 5 1 for the scenario k g s GFS WORK SIZI p P p P Sint32 wor Sint32 work stm STM WORK SIZI Sint32 brno StmHn stmtbl KEY MAX Sint32 bpl s
16. ncorrect or outdated information while reading through the attached document or come up with any questions or comments please let us know so that we can make the required changes in subsequent revisions Simply fill out all information below and return this form to the Developer Technical Support Manager at the address below Please make more copies of this form if more space is needed Thank you General Information Your Name Document number ST 136 D R2 082495 Document name Branching Playback Library User s Manual Corrections Questions comments Where to send your corrections 415 802 1717 Mail SEGA OF AMERICA Attn Evelyn Merritt Attn Evelyn Merritt Developer Technical Support Developer Technical Support 150 Shoreline Dr Redwood City CA 94065 1 Overview The Branching Playback Library BPL enables seamless reading of data streams based on a pre defined scenario This allows the system to branch between streams smoothly during reads The BPL however manages only the data streams that are necessary for branching Use a decode only library such as MPEG and Cinepak in conjunction with BPL to play back data such as audio and video 1 4 Organization of the Library Figure 1 1 shows the organization of CD related libraries Application oo Branching Iorary Playback CE CPK Library BPL File System Library GFS MPG
17. ning 0 Branch stream Equivalent to a file on a CD The BPL reads a stream based on a scenario that is set for a branch stream Different types of stream data e g audio video can be fetched by performing channel interleaving within a branch stream normally interleaving by means of a subheader Branch stream ID This ID identifies the branch stream Given this ID the read file stream key or destination information can be set or fetched Branch number This number specifies the branch destination Equivalent to the event types such as input from a control pad Table 2 2 List of abbreviations Abbreviation Meaning Description BPL branch play branching playback bstm branch stream branch stream bstmid branch stream ID branch stream ID brno branch No branch No bstmmax branch stream max Total number of branch streams brmax branch max Total number of branches Other terms that appear in this manual are based on the CD Communication Interface the File System and the Stream System Libraries 2 2 Restrictions on Names The BPL uses the following function variable type and macro names Function variable name BP and bp Type name Bp Macro name BP The libraries required by the BPL use the following global symbols Table 2 3 Symbol names and libraries LibariNamme X Symbol Stream System ST st St File System GF gf Gf CD Communication
18. nput Output Function value Function 20 Data Data Name Set branch stream information BPL_SetStmInfo Sint32 BPL SetStmInfo Sint32 bstmid Sint32 fid Sint32 nkey StmKey keytbl bstmid Branch stream ID 0Xbstmid bstmmax fid File ID nkey Number of stream keys nkeySBPL STMKEY MAX keytbl Stream key table None Error code Assigns branch stream information information on the individual streams that are actually read to a branch stream a Byassigning multiple stream keys to a file the function can read channel interleaved data b The maximum number of stream keys that can be assigned to a branch stream is BPL STMKEY MAX The BPL Init function specifies the total number of stream key types that can be used in all streams Data Data Name Get branch stream information BPL GetStmInfo Sint32 BPL GetStmInfo Sint32 bstmid Sint32 fid Sint32 nkey StmKey keytbl bstmid Branch stream ID fid File ID nkey Number of stream keys nkey XBPL STMKEY MAX keytbl Stream key table Number of destinations that are already set an error code results if this number is negative Gets the branch stream information that is assigned to a branch stream Refer to the destination information setting function BPL SetBranchInfo for the number of destinations Title Data Data Name Function Set destination information BPL_SetBranchInfo specifications Format Sint32 BPL SetBran
19. on TRUE state 6 2 Constants Title Data Data Name No Data specifications Constant 2 0 1 Error Codes The value of BPL_ERR_OK is 0 Other error codes take negative values Constant Description K Normal termination Too many stream keys Too many destination settings TBST ID Illegal branch stream ID N Illegal branch number RS Destination already specified No corresponding stream key set Stream open failure ES il 5 S ARE 5 iB Z UJ W W W ro td bE ulmltm MI os J l UJ J Tj H O 2 Other Constant Value Description gy v1 Number of stream keys that can be set to a branch stream Branching Playback Library User s Manual 17 7 Function Specifications Table 7 1 shows a list of BPL functions Table 7 1 List of functions 1 Function Function Name No Scenario processing 18 i processing Get destination stream 2 6 S EGA 7 1 Scenario Processing Title Data Data Name No Data specifications Initialize branching playback BPL_Init 1 1 Format Sint32 BPL Init Sint32 bstmmax Sint32 brmax Sint32 keymax void work Input bstmmax Total number of branch streams brmax Total number of branches keymax Total number of stream key types work Work area Output None Function value Error code Function Initialize
20. s the work area for the BPL Clears previously set scenario information Execute this function before the BPL is used Remarks a Determine the size of the work area from the BPL_WORK_SIZE bstmmax brmax keymax byte Allocate work areas at 4 byte boundaries Example Uint 32 work BPL WORK SIZE bstmmax brmax keymax sizeof Uint32 b When stream keys of different types are assigned to different branch streams the sum of the types is the value of keymax Example If key1 3 types of keys is assigned to bstm1 and key2 4 types of keys is assigned to bstm2 then keymax which is the sum of key1 and key2 will be 7 If key1 is assigned to both bstm1 and bstm2 then keymax which is key1 will be 3 c The BPL_Init function does not close the stream group that is currently used To force an initialization of the BPL while it is being used execute the BPL Reset function Title Data Data Name No Data specifications Reset branching playback BPL Reset 12 Format Sint32 BPL Reset void Input None Output None Function value Error code Function Suspends access to a branch stream and resets the branching playback closes the stream group currently being used by the BPL and initializes all information Branching Playback Library User s Manual 19 Title Function specifications Format Input Output Function value Function Remarks Title Function specifications Format I
21. t from applications based on the examples described herein It is possible that this document may contain reference to or information about SEGA products development hardware software or services that are not provided in countries other than Japan Such references information must not be construed to mean that SEGA intends to provide such SEGA products or services in countries other than Japan Any reference of a SEGA licensed prod uct program in this document is not intended to state or imply that you can use only SEGA s licensed products programs Any functionally equivalent hardware software can be used instead SEGA will not be held responsible for any damage to the user that may result from accidents or any other reasons during operation of the user s equipment or programs according to this document NOTE A reader s comment correction form is provided with this document Please address comments to SEGA of America Inc Developer Technical Support att Evelyn Merritt 150 Shoreline Drive Redwood City CA 94065 SEGA may use or distribute whatever information you supply in any way it believes appropriate without incurring any obligation to you 11 2 94 002 SEGA SEGA OF AMERICA INC onsumer Products Division Branching Playback Library User s Manual Doc ST 136 D R2 082495 1995 SEGA All Rights Reserved READER CORRECTION COMMENT SHEET Keep us updated If you should come across any i
22. tat Sint32 decode stat DecodeHn dc hn NULL Bool chgsw OFF Bool endflag FALSE Sint32 ret Initialization of the libraries GFS_Init STM_Init initDecoder setScenario Branching playback BPL SetStart BSTM1 ID BPL GetCurStm KEY MAX dc hn createDecodeHn while endflag FALS bpl stat chgsw OFF STM ExecServer decode stat decoder the switch case BP bpl stat L SVR COMPL stmtbl stmtb1l E BPL ExecServer chgsw TRUE endflag break case BPL SVR WAITS br EE Get pad inp no brno gt 0 BPL Selec break case BPL SVR SEL case BPL SVR NOB if decode s break ED ED ut ECE RN tat Branching Playback Library User s Manual COMP LI BSTM_MAX KEY_MAX sizeof Sint32 GRP MAX BSTM_MAX KEY_MAX sizeof Sint32 I X execDecoder dc hn 0 button A getPadEvent cBranch brno ED Branch number Stream handle table Branching playback status Decoder operation status Decoder handle Branch execution switch Initialize the File System Initialize the Stream System Initialize the decoder Set a scenario see 5 1 Specify a stream to begin playback Fetch the first branch stream Create a decoder handle
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