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DM355 mpeg4 decoder and source of green noise

Vim Venture
Intellectual 300 points

Hello,

I have a video file that has been run through the ArcSoft Mediaconverter tool to convert it to a format compatible with the DM355.  I extracted the mpeg4 elemental stream using ffmpeg.  I can look at the elemental video (with a m4v extension) using VLC on the PC and playback is fine.  I change the extension to .mpeg4 and play it back using the decode demo.  Frustratingly, I wind up with some strange green noise coming up in waves from the bottom of the screen.  See the attached pics.  The green IS dependent on what is happening in the video.  If the video is moving down, off the bottom of the screen, no noise appears.  If the video is moving UP towards the top of the screen, this green nonsense gets dragged into the picture.  Plus there are a few lines of white noise at the bottom that are not seen in the original or viewing with VLC.

Any ideas?

  • 0
    TI__Mastermind 41665 points

    The green reminds me of luma/chroma swapping though I am not sure how much that helps in this case since I am not sure why that would happen with the MPEG4 decoder. This probably means there is something about the stream that the DM355 codec simply does not handle. Do you get any warnings or errors out of the codec when running the stream? Do you get the same artifacts on the output if you use DVTB to play the stream on the DM355?

  • 0 in reply to Bernie Thompson TI
    Intellectual 650 points

    This can happen if you don't send reference IDR frames in the bit-stream - try to ensure your encoded video has proper reference frame generation (though VLC plays it back fine, so it is puzzling..)

  • 0
    TI__Expert 5145 points

    I think green pixels come from UMV decoding.
    DM355 MPEG-4 decoder does not handle UMV by default.

    Could you please confirm if UMV decoding is enabled or not?

    I do not know about white noise.

  • 0 in reply to Tetsu10133
    Intellectual 300 points

    OK!  Turning ON UMV decoding in DVTB gets rid of the green slime.  So the ArcSoft Mediaconverter tool must have this enabled.  There are very few user settings in this version of the tool.  Is there any chance that TI can get an expanded version of the tool with more control over the final settings?

    The green is gone with UMV enabled, but the few lines of noise are still present at the bottom of the video.

    Still working on how to enable UMV in my own code.

    Thanks,

    -Vim