Sound out of sync joining .avi files

Discussion in 'DivX / XviD' started by Henderson, Jan 1, 2007.

  1. Henderson

    Henderson Member

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    I have 13 .avi files from an old movie that I'd like to join, but the sound is always way out of sync when finished.

    I've tried Blaze Media Pro with various framerate settings, as well as VirtualDub. The .avi files are identical formats, all ripped with ImTOO DVD Ripper. Each .avi file is perfectly in sync, so it's not a problem with starting out with bad files.

    What am I doing wrong? I followed the VirtualDub guide that's posted here at AfterDawn.
     
  2. celtic_d

    celtic_d Regular member

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    Problems can arise if the audio and video streams aren't the same length and/or if the joining app does take into account delays.

    For instance the first part could be:
    VVVVVVVVVVVVVVVVVVVVV
    AAAAAAAAAAAAAAAAAAAAAAAAAA
    The file will play fine by itself, but the audio stream is actually longer than the video so when you join, the audio for the second part starts 5 A's too late.

    Try AVISynth with ++ to join, so
    part1 = avisource("001.avi")
    part2 = avisource("002.avi")
    part1++part2

    See if that plays in sync. If so then you could save out the audio, then mux with your original video.
     
  3. aldaco12

    aldaco12 Active member

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    Otherwise, encode each AVI into mpeg THEN multiplex the two parts.
    Sinche when you encode AVI -> MPG video and audio must match (and the movie's length is decided by the video).
    [bold] The MPG length will be the Video's length [/bold]

    That is:
    1) in the
    VVVVVVVVVVVVVVVVVVVVV
    AAAAAAAAAAAAAAAAAAAAAAAAAA
    example, the MPG will be:

    VVVVVVVVVVVVVVVVVVVVV
    AAAAAAAAAAAAAAAAAAAAA
    MMMMMMMMMMMMMMMMM
    with five 'A's which have been 'cut off'.

    2) in the
    VVVVVVVVVVVVVVVVVVVVVVVVVVV
    AAAAAAAAAAAAAAAAAAAAAA
    example, the MPG will be:

    VVVVVVVVVVVVVVVVVVVVVVVVVVV
    AAAAAAAAAAAAAAAAAAAAAAAAAAA
    MMMMMMMMMMMMMMMMMMMMMM
    with the last five 'A's which will represent silence.

    If you de-multiplex the audio, you can use it, when you author the DVD using elementary streams.

    If you choose a simple mpeg format (e.g. MPEG-2 CBR, which is faster than MPEG-2 VBR even if it has lower video quality) you'll speed vey much the process. It's useful, since you won't use the video output but only the audio one.
     
    Last edited: Jan 2, 2007
  4. MysticE

    MysticE Active member

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  5. Henderson

    Henderson Member

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    After playing with the files for another several days, the final avi file was always out of sync. So I went about it from the other end.

    I tried Xilisoft's DVD Ripper Platinum and it was able to rip the dvd files into one avi file, instead of one for each chapter like ImTOO DVD Ripper does. And it's in perfect sync.

    Thanks much for all the help and suggestions. I hope I never have to try doing that again. :p
     

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