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HDMI video compression

Danny U
Prodigy 90 points

Hi All,

I'm using a EVM365 board and am trying to test video compression. As the EVM board can get only component video (720P), I'm using a laptop with HDMI output as a video source (playing a 720P video), The other side of the HDMI cable is hooked to a HDMI-COMPONENT video converter which feeds the EVM board.
All this is very nice except it doesn't work. The encode utility can't run as it says that the video resolution is not recognized (it's looking for an exact resolution which is one of a default list or is capable of being divided to 16 with no remainder). My idea of using a lapto was in order to get a tool which is easy to change resolutions and/or video parameters thus checking the EVM software & hardware robustness and compression/decompression quality. 

Next I tested the video on a HD-TV. I simply hooked the HD cable directly from the laptop to one of the TV's HDMI inputs and found out that the picture shown is not fully alligned as been seen on a PC monitor using it's HDMI input. I guess that that's the reason why the encode wouldn't run (it's looking for a precise 1280X720).
At this point it seems like the TV is translating the video input wrong (although it says that the input is 720P @ 60Hz which is correct). It can't be that the laptop is producing
a wrong resolution as has been proven on the PC monitor (or maybe a PC monitor has the capability to adjust the input to specific resolutions better than a TV?)

My question is actually the following - can I use a HDMI output from a PC in order to feed the EVM board or only a dedicated video source (HD camera or BLUE-RAY player) would do fine? Has anyone tried using such setup and can recommend which is better?

Thank you for any comment on this matter,

Danny

 

  • 0
    TI__Mastermind 43875 points

    Danny,

    PC monitors are usually able to accept many more resolutions than a TV. Most TVs have a very limited number of supported resolutions and you should check the user guide for your specific TV to determine exactly which ones are supported. If you then change your laptop output to match one of these resolutions you should get a stable and correct picture.

    You may need to use third party software on your laptop in order to be able to select all the resolutions you want since Windows often limits the resolutions you can select . Something like Powerstrip should work.

    Regarding the DM EVM, you are correct in that I believe the particular demo currently only accepts specific formats/resolutions so you need to configure your source accordingly.

    What resolution did you configure your laptop HDMI output to?

    Finally, depending on which HDMI to component converter you may or may not be able to use a protected source such as a Blu-ray player.

    BR,

    Steve

  • 0 in reply to Steve Clynes
    Prodigy 90 points

    Thank you, Steve

    The resolution of my laptop is 1280X720 (which is the classic 720P). Maximum resolution 1366X768.

    Let me rephrase my quesion:

    My EVM encode software can't run because it doesn't recognize the input video's resolution as it's probably not exactly 720P.
    It seems like the HDMI to converter COMPONENT unit changes the video resolution. I can see on the TV that indeed the picture is not
    exactly the same as on the laptop (some parts on the top & bottom are missing and the picture is bit shifted to the left).

    I saw that the encode software is expecting a resolution which is defined and if not found then it doesn't work. Is there a way to overcome
    this in both sides (encode & decode) by not checking the resolution? Obviously if the encoder will ignore specific resolutions, the decoder will have
    to know the exact parameters to use in order to succeed in decoding the compressed video.
    Can anyone recommend a HDMI to COMPONENT converter unit which is able to convert without changing the input at all (i.e. transparrent convert).

    I hope this better clarifies my question.

    Thank you,
    Danny