Using HDMI Guide
Contents
1. J S Technology Ltd 2012 Page 10 Technology 11 An Alternative Convert HDMI to HD Component Video YUV YPbPr Not every display has an HDMI connector but they may have another high quality input the YUV YPbPr Component video input How does one change HDMI to YUV The solution is to use an HDMI to YUV YPbPr Component video converter Figure 13 Both HDMI and YUV Component video are similar in terms of quality so with a high quality video converter there will be no degradation in picture quality Additionally due to the complex nature of HDMI in muti display environments it s sometimes more desirable to use YUV YPbPr component video where there are few problems with distributed video For this very reason some professional installers prefer to convert HDMI to YUV to ensure compatibility for their clients HDMI Input YUV YPbPr and audio Output The HDMI to YUV YPbPr Component Video Converter Figure 13 An alternative to solving incompatibilities with HDMI In addition to HDMI to Component Video converters there are other options Conversion to DVI is possible but this will typically only allow for a PC monitor to be used Using DVI will typically maintain HD video resolutions but in some cases it s a standard definition signal that s required It may be desired to connect and HD source with a standard definition TV or even data projector where HDMI or component video isn t available For that the option2. as it then can only accept 720p or 10801 resolutions A Full HD or Full 1080p screen will be able to accept 1080p Unfortunately there is no standard which guarantees that the HD screen is indeed one which is able to accept 1080p and the best advice is to look for a 1080p marking on the screen or in the TV s specifications The examples below in Figure 12 show how a mixed HD Ready and Full HD screen will operate When the higher resolution screen of a Full HD model is mixed with a lower HD Ready screen the system will select the highest common resolution This resolution will either be 10801 or 720p and not 1080p Only when the Full HD screen is mixed with a similar one will it be able to display the full 1080p picture In this example we re showing the HD Ready with a 720p picture as this is its natural resolution Often the screen will select 10801 an interlaced mode as its default resolution It is suggested that if the source is able to run as high as 1080p then it s best to change this to 720p for use with an HD Ready display This is because it will better match the displayable lines than allowing the sources to automatically select 10801 as they will typically do Often it is sufficient to switch off the HD Ready screen when only wishing to view on the Full HD screen at 1080p It s not uncommon however that the output video resolution settings in the source have to be readjusted again to 1080p HD Ready Scree
3. switch It combines the features of both the switch with splitter and cross over switches in to one unit allowing for each output to select an input which is either different from or the same as any other output Itis more complex than the previous examples with multiple switching circuits and multiple splitters inside the one unit The left hand example of Figure 10 replicates the switcher with splitter function where both outputs are able to display the same input In the right hand example using the same connections as previously each display is able to select a different source similar to the way the cross over switch would work The advantage with a matrix switch is the flexibility that it offers to select any input for any output Using HDMI Guide Sy J S Technology Ltd 2012 Page 8 Technology SOURCE 1 SPLITTER SOURCE 1 SPLITTER 30 we 2 SWITCHING L N o DISPLAY 1 SPLITTER SPLITTER a DISPLAY 1 SWITCHING L j ne SPLITTER d DISPLAY 2 SPLITTER i Es DISPLAY 2 2 SWITCHING l SWITCHING SPLITTER SPLITTER Both switches are set to the same input source Top switch selects source 4 for display 1 green therefore both displays show the same pink Lower switch for display 2 selects source 2 tan Figure 10 Matrix switching where each switch can select any source without prejudice An example of a Matrix switch is shown in Figure 11 for 4 inputs with
4. HDMI This may be a strange question to ask in a guide to HDMI However this is an important question HDMI has been seen as the connector for HD or High Definition video yet before HDMI there was component YUV YPbPr and also DVI connections In the professional video world there is also the SDI interface see Figure 1 Each of these connection types gives similar results 1 As we will see later there are other means in which to connect HD video to a display Using HDMI Guide J S Technology Ltd 2012 wy Page Technology Component Video DVI Connector HDMI connector SDI is carried by co ax typically three phono cable and terminates on RCA connectors a BNC connector Figure 1 Several types of connection for High Definition Video HDMI has been promoted for domestic use because it is a closed system It has within it HDCP a means to restrict the use of the HD content Not only does the HDMI have this protection but also licensing terms enforce manufacturers of video sources that include HDMI to restrict the resolution of other outputs 2 Therefore the consumer is not given a free choice of which connection scheme to use but is forced to use HDMI Displays and sources which were HD compatible before the HDMI connector or had additional outputs are being made obsolete by these conditions HDMI has in place key restrictions which seem monopolistic Therefore in a consumer video situation the answer is Y
5. They re terminated in an RJ 45 connector as shown in Figure 4 below Most PCs and laptop computers will have a socket for a LAN interface using this type of connector Although the connections are the same HDMI over CATSe CAT6 systems should not be connected to a computer network but have their own dedicated cables Using HDMI Guide J S Technology Ltd 2012 Iy Page 5 Technology An RJ 45 connection on a CATS5e CAT 6 network lead Figure 4 A typical network connection 7 HDMI Switching With so many different sources all using HDMI there simply isn t enough inputs on a TV and worse for other display types such as projectors There has to be a means to switch these sources Simple switches Figure 5 act upon the most recent active source to automatically switch over Others require the user to switch using an IR remote control Figure 6 HDMI SCREEN OUTPUT INPUTS o HDMI SOURCE 1 HDMI SOURCE 2 HDMI SCREEN OUTPUT INPUTS p Da aS SS ap HDMI SOURCE 1 HDMI SOURCE 2 HDMI SOURCE 3 HDMI SOURCE 4 Four input HDMI switch Controlled by via remote control Figure 6 HDMI switching for four sources Using HDMI Guide wy J S Technology Ltd 2012 Page 6 Technology 8 Multiple Displays Although without doubt HDMI has been designed as a single ended system where one source 1s connected to one display it is possible to use splitters This is a very bad term as the signal isn t split a
6. for networking Since most home systems will already be operating at 1080p the leads will already be High Speed Only where a system will specifically use the HDMI Ethernet channel will leads have to be upgraded as this is a new feature that was not supported previous to V1 4 4 6 HDMI Long Lengths HDMI leads up to 25m can be found but are rare and costly Generally it s considered that 10m is a safe limit for HDMI For longer lengths another means for transporting the HDMI signal should be considered The most common solution is an HDMI to CATSe CAT6 converter as shown in Figure 3 Distances of up to 60m at Full HD have been claimed with CATSe CAT6 cabling costing as little as 20p per metre 5 HDMI SCREEN CATS 2 CATS5 1 OUTPUT To SENDER Ei RECEIVER CATS5 1 CAT5 2 HDMI SOURCE An example of an HDMI to CATSe CAT6 Interface and its use Figure 3 An alternative solution for transporting HDMI over longer distances These devices will allow the HDMI signal to be carried over inexpensive CATSe CAT 6 cables as used in computer networking At the source there is a small box to convert the connection from HDMI to an RJ 45 network type connection where the CATSe CAT 6 cables will attach On the distant receiving side is a similar box converting the signal back to an HDMI connector Operation of these is typically transparent to the user CATSe and CAT 6 are types of cable used in computer networks
7. we show in Figure 16 The MAIN HDMI output would carry the 3D picture to the screen with audio being routed to the amplifier via the SUB HDMI output Even with this solution other control functions have to be switched off to allow for the output audio to be forced into HD mode Rear of a Panasonic Blu Ray Player Note Dual HDMI output Highlighted 9 Figure 16 Some HDMI sources have resorted to using multiple outputs to avoid incompatibilities When using a source with two HDMI outputs such as the one discussed above the sub HDMI feed goes directly to the amplifier for HD Audio and the main feed for picture goes to the screen The diagram in Figure 17 details how to connect these up It is typical that the sub or audio output HDMI has also a basic low resolution picture included Although not shown it is common to also have a connection from the amplifier to the TV to allow for the setting up of the amplifier and to adjust the audio levels of the surround sound speakers 3D TV Screen HDMI Interface Home Cinema Amplifier Not 3D aware INPUT OUTPUT a a OUTPUTS SUB MAIN 3D TV HDMI SOURCE How to use a 3D source with Dual HDMI outputs One output is dedicated for 3D video while the other contains the audio with a low resolution 2D image Figure 17 3D imagery and HD Audio are being connected separately to avoid incompatibilities Using HDMI Guide J S Techn
8. 2 outputs On the rear are the two output HDMI connectors and a group of four input connections The front display has indicators to highlight which input has been selected This type of unit is supplied with an IR remote control but also has two front mounted selection buttons HDMI SCREEN B HDMI SCREEN A OUTPUTB OUTPUTA INPUTS o D UD HDMI SOURCE 1 HDMI SOURCE 2 HDMI SOURCE 3 HDMI SOURCE 4 Matrix switch with four inputs and two outputs Figure 11 An example of a Matrix switch 10 The Pitfalls Multiple Displays It would seem that HDMI was conceptualised from the very start as being a single source to a single screen Much like DVI for PCs where the source PC is under the desk of the monitor and that only one monitor would be driven off that single connection However in a home environment it s not uncommon to have multiple screens driven off the one source Main living room TV Bedroom TV Kitchen TV Projector for movies or sports HDMI only outputs one video stream and that is of a certain resolution Therefore all the screens must support that same resolution otherwise it will default to the highest common resolution This may mean Using HDMI Guide wy J S Technology Ltd 2012 Page 9 Technology that in the main living room the TV won t receive the 1080p signal it can handle because the bedroom TV can only accept 720p There is also a common misunderstanding when a TV is marked as HD Ready
9. DMI outputs as a work around for these problems It s been shown that the need for expensive highly advertised branded leads simply doesn t exist as an inexpensive unbranded lead will give the same quality of picture This is because the link is digital and both types of leads carry exactly the same information For long cable lengths HDMI simply isn t as robust as the previous HD component video standard Where lengthy runs are required it is advisable to convert HDMI to run on CAT5e 6 network cabling instead as this offers easier cable management and reduced costs compared to long HDMI leads Multiple sources and multiple displays can cause issues with a lack of inputs on a screen and the splitting of the HDMI signal Care should be exercised when selecting either switchers or splitters Often just trying a different switch or splitter can help Although no guarantee of compatibility can be given it is best to buy from a company who tests for real world compatibility with a range of sources and screens such as J S Technology Ltd It may be that the best means to overcome incompatibilities within the HDMI standard for splitting and distribution is to convert to an alternative format such as component video YUV YPbPr HD video is supported with fewer problems when distributing switching or using longer cable lengths With a source which offers an HDMI output but lack a standard video outputs such as Apple TV V2 amp V3 Using HDMI Guid
10. ES it has to be HDMI 3 Which Version of HDMI HDMI has been developed in the public eye Version 1 4 is the latest but 1 2 and 1 3 devices are common Table 1 Although backward compatibility is claimed for HDMI as we ll see below with 3D this is not always the case It could be argued that the end user is expected to upgrade their products to cope with each iteration of HDMI po VO Full Resolution 1080p __ S Table 1 HDMI versions and their salient features 3 N lt lt A brief description of each of these features is given below Full Resolution 1080p The typical resolution for Blu Ray and games consoles 192kHz 24 bit audio This defines the included audio stream within the HDMI feed DVD Audio Support A new type of CD audio for improved sound quality Super Audio CD A new type of CD audio for improved sound quality Using HDMI Guide J S Technology Ltd 2012 Page 2 Technology Deep Colour The ability to show a larger range of colours using a higher precision numbering system Auto Lip Sync To automatically adjust for delays between audio and the displaying video HD Audio Support for Dolby TrueHD and DTS HD Master Audio Stereoscopic 3D Defines 3D modes HDMI V 1 3 has also been shown to support 3D Ethernet Channel Network interface between connected devices Note The stated compliance with a version does not imply that all features are available Fo
11. Using HDMI Guide Technology A technical briefing by J S Technology l Introduction l 2 Does it Have To Be HDMI i a Which Version of HDMI 2 4 HDMI Cables Which to buy 3 ae HDMI Version Number Verses Standard and High Speed Leads 4 6 HDMI Long Lengths 5 7 HDMI Switching 6 8 Multiple Displays 7 9 Multiple Inputs and Multiple Outputs 7 10 The Pitfalls Multiple Displays 9 11 An Alternative Convert HDMI to HD Component Video YUV YPbPr 11 12 3D TYV and HDMI 12 13 The Mixing of 3D with HD Audio 12 14 3D with Multiple Displays 14 15 Future Technologies and HDMI Alternatives 14 16 Conclusions 16 17 References 18 1 Introduction HDMI is the new SCART connector An all in one connector covering both video and audio interfacing between your A V source and display It promises HD video and audio and the very latest versions also include networking Yet HDMI isn t without its problems Multi display environments often highlight the complex nature of HDMI and its incompatibilities In HDMI s short life there have already been several versions Recently support for 3D TV has been added creating further incompatibilities with existing hardware Then there s HDCP the copy protection system which is often blamed for preventing the smooth operation of an audio visual system In this guide we ll cover some of the connection methods and the drawbacks of HDMI 2 Does it Have To Be
12. Video Which is Better February 2005 Online Available http www ecoustics com electronics products articles 122868 html 2 What is HDCP Online Available http www digitalconnection com faq HDTV_12 asp 3 HDMI Versions Online Available http en wikipedia org wiki Hdmi Versions 4 J Knott When Do You Need High Speed HDMI Electronic House January 2010 Online Available http www electronichouse com article when_do_you_need_high_speed_hdmi Accessed April 2012 5 CAT6 CCA C6 UTP Ethernet Network SOLID Cable Reel Box Wire 305m Kenable Online Available http www kenable co uk product_info php products_id 4172 Accessed April 2012 6 Quantum Data 20112 Online Available http www quantumdata com 7 Titanic Movie Twentieth Century Fox 2012 Online Available http www titanicmovie com Accessed 2012 8 Quality warnings issued over 3DTV BBC June 2010 Online Available http www bbc co uk news 10446419 Accessed 2012 9 Panasonic BMP BDT310 User Manual Online Available http service us panasonic com OPERMANPDF DMPBDT310 MUL PDF 10 A Koebel Digital cinema projection choosing the right technology 2011 11 M Warman The Telegraph September 2011 Online Available http www telegraph co uk technology news 8779777 Internet connected TV overshadows 3D html 12 Love Film 2012 Online Av
13. ailable http www lovefilm com 13 DisplayPort Online Available http www displayport org 14 Thunderbolt Intel Online Available http www intel com content www us en 10 thunderbolt thunderbolt technology developer html 15 Multi Monitor Net 07 2008 Online Available http multimonitor net 2008 07 well designed commercial racing cockpit 16 D J Sim Connecting Apple TV V2 amp V3 toa SCART S Video Composite Input J S Technology Ltd March 2012 Online Available http www js technology com store info av guides connectingappletvv2 pdf Accessed April 2012 Version 1 00 J S Technology Ltd Release Date 04 2012 APL Centre Author Dr John Si i uthor r John Sim Stevenston Industrial Estate J S Technology Ltd can not be held responsible for any Stevenston loss damage or injury arising from use of this Ayrshire information All information is believed to be accurate KA20 3LR United Kingdom Using HDMI Guide J S Technology Ltd 2012 a Page 18 Technology
14. becoming aware of the internet and with newer models also supporting hard drives it s clear that movie rentals streamed over the internet and stored on a local drive is the future In a world of internet TVs the notion of an external player containing the source material that then requires a video connection to the screen doesn t exist the TV is its own combined source and display 12 WiFi and Ethernet cables are common in the modern home Figure 18 WiFi and LAN interfaces An internet TV typically has an Ethernet connection with the option of WiFi and both of those interfaces are well known technologies Figure 18 There is already sufficient infrastructure within many homes to allow for a TV to be easily connected to the internet Adding an internet TV does not require other items to be upgraded as it can do with HDMI DisplayPort has also been proposed as an alternative to HDMI Without the restrictive licensing terms of HDMI for manufacturers it s a more desirable proposal certainly in PC terms than DVI One major advantage of DisplayPort is the ability to drive a number of monitors off a single connection It is able to display the same image on a number of monitors or a different image over various monitors 13 As it Using HDMI Guide J S Technology Ltd 2012 Page 14 Technology stands DisplayPort already supports 4k video resolution deep colour and 3D This type of connector shown in Figure 19 will pr
15. e J S Technology Ltd 2012 vy Page 16 Technology video converters are available from J S Technology which make the connection to a standard display possible See our guide to connecting Apple TV V2 amp V3 16 For PCs the DisplayPort and Thunderbolt interfaces offer a better connection scheme more in keeping with their needs Multiple displays and the ability to connect many different types of equipment via Thunderbolt is an exciting prospect Even more exciting would be for future games consoles to make use of the ability to drive multiple displays for immersion gaming In the future domestic audio visual equipment may all be simply connected to the internet with music films and TV shows all streamed directly to the TV An internet connected TV uses the current networking infrastructure that is already available in most homes In that future there is no need for HDMI With limited ability to future proof any HDMI installation the advice can only be to choose the most appropriate switches splitters converters and leads required at the time It must be accepted that an upgrade may be required at a later date as the HDMI standard evolves or when new sources or displays are purchased Therefore the choice of which HDMI accessory to add to a system is dictated by the immediate requirements of the system Using HDMI Guide J S Technology Ltd 2012 Page 17 Technology 17 References 1 DVI vs HDMI vs Component
16. ed 15 Multiple monitors have been used in flight simulations to give a separate instrument display from that of the flight path but are also now being used to give a more complete surround view for other types of games The example in Figure 21 shows a car racing game being played HDMI doesn t have the native ability to connect up multiple monitors whereas DisplayPort and Thunderbolt already have this within their standard Using HDMI Guide J S Technology Ltd 2012 Xy Page 15 Technology Three monitors offer surround viewing capability This example is for car racing but flight simulation and role playing are also possible Figure 21 Multiple monitor gaming example featured on http multimonitor net Future games consoles may opt for DisplayPort or Thunderbolt to offer native multiple display support There are simple adaptors to allow these types of connection to be converted to HDMI for backward compatibility therefore there is no need for HDMI to be offered on the consoles too 16 Conclusions The consumer has been forced to use HDMI and with it face various incompatibility issues While a single source to one display typically doesn t have any problems mixing various sources and multiple screens can raise serious questions on the viability of HDMI as a standard Further the new breed of 3D TVs has shown more limitations and incompatibilities in HDMI Some source manufacturers have been forced to provide multiple H
17. ier switching off the 3D video stream It then leaves the viewer with a choice of having no 3D but HD audio or 3D picture but no HD audio Neither case is satisfactory 3D TV Screen Non 3D HDMI nerace Home Cinema Picture INPUT OUTPUT OUTPUT 3D TV HDMI SOURCE Routing HDMI via a non 3D aware external amplifier to use the audio information contained within the HDMI stream Because the amplifier is not 3D aware it will refuse to accept 3D video resulting in only 2D imagery on the screen Figure 15 How HDMI with 3D and HD Audio conflicts when not all systems are 3D compatible Using HDMI Guide J S Technology Ltd 2012 Page 12 Technology Before HDMI this wouldn t have been a problem as digital audio was carried separately via the TosLink system either an optical or an electrical connection It would also have been easy to split or buffer the video or audio between both the amplifier and the screen However even if we tried an HDMI 1 to 2 splitter this would fail The HDMI system would still default to the non 3D picture It is expected that the owner changes the amplifier to a newer model just to support the 3D video stream in addition to already having to upgrade their sources and screen Fortunately some models of Blu Ray players have adapted to this issue and are now supporting dual HDMI output connections with one for video and one for audio One example is the Panasonic BMP BDT310 whose connections
18. n Full HD Screen Full HD Screen Full HD Screen 720p 1080i 720p 1080i 1080p 720p 1080i 1080p 720p 1080i 1080p OUTPUTS OUTPUTS INPUT INPUT y oe Full HD 1080p HDMI SOURCE Full HD 1080p HDMI SOURCE With mixed HD Ready and Full HD screens the resolution defaults to the most When two Full HD screens are mixed it is possible compatible resolution which is lower than the to run both at the full 1080p resolution Full HD screen can display HDMI 1 2 Splitter HDMI 1 2 Splitter Figure 12 The difficulties in mixing displays of different resolutions Further there are just simple incompatibilities It may not be possible for whichever splitter that you choose to share the HDMI to find a common and compatible screen resolution It s been observed that even just routing from one source through a switch to a screen for the source to default to a lower resolution than is possible with a direct connection Or in some situations the HDCP protection system will not allow content to be displayed In these cases it is an incompatibility in the source the screen or even the splitter itself There is diagnostic equipment which will help establish the actual cause but it is expensive and not simple to use 6 For an end user updating each of the source s firmware is the best advice and trying alternative splitters If this fails then the displays or sources may have to be replaced Using HDMI Guide
19. nexpensive unbranded lead With longer leads it s more likely that missed edges of the HDMI signal will impact on the image as small white dots also known as sparkles Or the lead may simply not work at all but that same lead may work in another system It then becomes dependent upon the source and display equipment No guarantee can be offered by the manufacturers of the source or display or indeed the lead that a certain length will work See the next section for an alternative solution Longer lengths are also made from thicker cable than shorter ones therefore it may be more difficult to route the lead neatly Costs for these longer leads do increase but it is still not a justification to opt for an expensive highly advertised brand J S Technology deliberately doesn t stock branded cables for HDMI in the firm belief that they offer no advantage to the customer Only quality unbranded leads that have been tested and proven in a real world home cinema are stocked Using HDMI Guide J S Technology Ltd 2012 Page 3 Technology Inexpensive unbranded lead Highly advertised branded lead Figure 2 Comparison between two different leads and the resultant imagery 5 HDMI Version Number Verses Standard and High Speed Leads As discussed in a previous section there have been a number of different versions of HDMI Since a lead just creates a data link the minor differences between some versions of HDMI cannot affect pic
20. obably remain only on PCs B9 DisplayPort DisplayPort logo and typical cable Figure 19 An alternative PC monitor interface Apple and Intel have jointly worked on a new type of interface called Thunderbolt 14 Itis intended to be able to offer exceptionally high speed connections with multiple devices connected to the Thunderbolt chain It combines PCI Express with DisplayPort to allow for both monitors and external PC equipment such as hard drives and networking to be easily connected As with DisplayPort Thunderbolt can drive a number of external monitors not just a single one at high bandwidth f THUNDERBOLT Thunderbolt logo and typical cable Figure 20 A new type of display interface with the ability to connect other types of peripherals Thunderbolt can have up to 7 devices daisy chained off the one source but with the use of external hubs this can be extended further Thunderbolt can be carried on either copper wires Figure 20 or optical fibre with the latter able to transport over many tens of metres If Apple were to release a TV it would certainly be supplied with Thunderbolt At the moment only displays designed for computer use have so far been equipped with Thunderbolt There is sufficient capacity within Thunderbolt for future technologies to be carried on this interface Multiple monitors could be the next logical progression for games consoles following where games PCs have already progress
21. ology Ltd 2012 Page 13 Technology 14 3D with Multiple Displays Splitting the HDMI between a 3D screen and a 2D screen also causes problems Similar to the previous example where difficulties arise when sharing HDMI between screens of different resolutions the HDMI will default to a 2D picture Other than disconnecting the 2D screens there currently no known effective solution to maintaining a 3D picture 15 Future Technologies and HDMI Alternatives The future for HDMI is very reactionary and will depend upon any new technologies or developments both from the world of cinema and consumer electronics With the latest HDMI standard there is an increase in resolution with 4k 4 096 x 2 160 at 24fps images a possibility This is one of the standards for digital cinema 10 but as of yet there are no known sources of material for home consumption However digital cinema may in future opt for higher frame rates beyond what HDMI is currently capable of An increase in frame rate would most likely once again require another iteration of HDMI to support faster data rates than currently supported If anything the history of HDMI has shown is that it s not a future proofed technology For screen display interfacing perhaps the most important interface right now is the network connection With an ever increasingly connected world there is without a doubt demand for TVs to be connected to the internet 11 Be it WiFi or Ethernet TVs are already
22. our different sources but only one switching circuitry outputting to a splitter which then drives the two displays Using HDMI Guide wy J S Technology Ltd 2012 Page 7 Technology SOURCE 1 DISPLAY 1 SPLITTER DISPLAY 2 HDMI Switch with integrated Splitter Both output displays show the same picture pink Figure 8 HDMI switch whose output also includes a splitter function A cross over switch is one where each of the outputs can individually be connected from any of the inputs In effect a cross over switch is built from multiple switches all in the one unit There is a significant limitation with cross over switches in that each output must have a unique input selection and cannot both be connected to the same source at the same time It does not have any splitter functionality In Figure 9 the first output display 1 is connected to the first source pink just as the previous example Because of the limitation that no two outputs can select the same source the second display display 2 has to be changed over to a different input in this case source 3 yellow but it could have equally been source 2 tan or source 4 green SOURCE 1 2 are DISPLAY 1 gt ee Ae L i Ha i 2 2 pa w a SWITCHING Cross over switches allow each output to select a unique input Figure 9 A type of HDMI switch with multiple switching circuits The third device type is the matrix
23. r example a V1 4 device may not have the Ethernet channel included 4 HDMI Cables Which to buy There can be no justification for over spending on HDMI leads When dealing with digital signals you get the same information on an inexpensive cable as you do on highly advertised and expensive branded cable It s similar to sharing digital photos from one mobile phone to another It s made a digital pathway from phone to phone through the ether and yet the picture is identical Same with HDMI it s a digital connection An inexpensive cable need not be a poor quality one To illustrate that an inexpensive unbranded lead will give an identical picture to an expensive branded lead an experiment was carried out Using a well known brand against an old and unbranded lead The branded lead is the very latest HDMI 1 4 compliant lead with the Ethernet channel whereas the unbranded is one of the oldest that could be found Both are 2m long The source was a Blu Ray player connected to a plasma screen Both tests were conducted at 1080p and verified to be at 1080p Each picture was taken on a DSLR camera and has only been cropped by GIMP to remove the excess boarder No other image manipulation has been performed Figure 2 shows the resultant images As can be seen from the images below there is no difference in results from the two leads tested The expensive highly advertised branded lead gives a clear and vibrant pictures however so does the i
24. s are to convert HDMI to either SCART S Video or Composite video An example is converting Apple TV which only has an HDMI output V2 and V3 to anormal TV Two such converters are shown in Figure 14 HDMI to SCART Converter HDMI to S Video and Composite Converter Figure 14 Two solutions to connecting HDMI to standard inputs Using HDMI Guide J S Technology Ltd 2012 Page 11 Technology 12 3D TV and HDMI Cinemas have had a resurgence of 3D projection with some of the biggest films recently being in 3D Even some older films are being re mastered and released in 3D 7 With films being produced in 3D an outlet for the home was the next obvious step 8 Initially HDMI did not support 3D but some HDMI V1 3 devices were seen to start supporting 3D content in a limited fashion With HDMI V1 4 a much larger range of 3D resolutions and modes are supported within the standard 3 However there are two serious issues that have been discovered by professional installers and others 1 Audio being routed via an external amplifier 2 Multi display systems These will be covered in the next sections 13 The Mixing of 3D with HD Audio Remember that HDMI carries audio as well as video The HDMI must then be routed via an amplifier to gain access to the audio streams and especially the HD audio content see Figure 15 This creates a problem that the amplifier may not understand the 3D video signal which results in amplif
25. t all Rather the input signal is regenerated and passed to each individual output as a fresh copy As the information is digital there is no loss in quality when creating these copies In Figure 7 there are two examples of HDMI splitters one for connecting two displays and another for four Ideal applications for these would be where there is a flat screen TV for general viewing and a projector for occasional use ee ee HDMI SOURCE HDMI HDMI HDMI HDMI SCREEN 1 SCREEN 2 SCREEN 3 SCREEN 4 INPUT OUTPUTS Co HDMI SOURCE Top images 1 to 2 outputs Lower images 1 to 4 outputs Figure 7 Distributing HDMI to multiple displays 9 Multiple Inputs and Multiple Outputs There are three types of device that have multiple inputs and outputs Firstly there are switches which also incorporate a splitter within the one unit Secondly there are cross over switches where each output can be connected to an individual input but no two on the same input as they lack the splitter functionality Finally there are Matrix switches which can further allow any of the inputs to be routed to any of the outputs to show the same or different source When a switch is combined with a splitter it performs both functions in the one unit Firstly it is able to select between each of the inputs to the unit and secondly display this selected source to all its outputs This is shown in Figure 8 where there are f
26. ture quality Various companies have however used the introduction of a new HDMI version number to release a new range of leads suggesting a requirement to also upgrade the leads when upgrading other parts of the system Yet as demonstrated in the previous section even the very latest V1 4 lead gave the same picture as an old pre V 1 4 lead In a move claimed to bring clarity to the HDMI lead market the HDMI Licensing LLC company have created new classifications for HDMI leads to adhere to For those who license from HDMI they must not use an HDMI version number for the leads but rather these new classifications The salient ones for home use are e Standard HDMI Cable e High Speed HDMI Cable e Standard HDMI Cable with Ethernet e High Speed HDMI Cable with Ethernet Using HDMI Guide J S Technology Ltd 2012 Page 4 Technology Standard is considered to be a picture of 720p 10801 or lower without Deep Colour High Speed is able to handle all resolutions including 1080p and 3D The option of with Ethernet is required where an internet connected device is to be used via the HDMI lead although many devices have their own direct connection to the internet For example a Blu Ray player will have a LAN port for direct connection to the internet to enable the BD Live service While it is internet enabled it does not necessarily mean that a Cable with Ethernet is required as it may not be utilising the HDMI system
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