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compatability concerns? .avi w/parts w/different bitrates

Discussion in 'Other video questions' started by coyote2, Oct 13, 2011.

  1. coyote2

    coyote2 Member

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    If parts of an .avi file have different audio bitrates, will the file have compatibility issues with playback devices?

    The whole .avi file is CBR (MPEG-1 Layer 3 48000 Hz Joint Stereo), but one part's audio is 128 kbps and the other part's audio is 160 kbps.

    This is because I joined two .avi files to create it. Then I edited the audio (in mp3DirectCut) and remuxed the edited audio with VirtualDubMod 1.5.10.2 which gave me a warning because it thought it ("appears to contain a MP3 VBR stream") VBR. (I suppose because there were two regions with different CBR bitrates.)

    Avidemux didn't mind when I originally did the join. And the joined file plays perfectly on all *my* players and boxes. But I wonder if other players would have issues, so maybe I should rejoin after recoding one file's audio bitrate to match the other?

    [​IMG]
    You can click to view, or read here, the rest of the VirtualDubMod message: "The current preference is to rewrite the audio header with standard CBR values during processing for better compatability. This may introduce up to 33256 ms of skew from the AVI video stream. If this is unacceptable, (re)compress with a constant bitrate encoder. (bitrate 129.3 +-6.2kbps) Do you still want to rewrite the header? (only matters when saving to AVI)?" Then I clicked "No" and saved the .avi
     
    Last edited: Oct 13, 2011
  2. attar

    attar Senior member

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    My experience is that when either the freq sample rate or the data/bitrate of the audio is different, VirtualDub (and the old VirtualDubMod) will refuse to join the files.

    AviDemux accepts the files and joins them - but the second part is out of sync unless the audio is explicitly re-comprssed (ie not set to copy).

    As far as VBR audio in AVI, both my DivX certifed standalone DVD players show sync and freezing problems.
     
  3. coyote2

    coyote2 Member

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    Thank you very much, attar!

    Until your post I didn't notice, but I see the 2nd part is a very small amount out of audio sync. I'll do it right now.
     

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