1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Fix FLV Sync Issues

Discussion in 'Other video questions' started by jkonrad, Apr 29, 2008.

  1. jkonrad

    jkonrad Member

    Joined:
    Apr 29, 2008
    Messages:
    2
    Likes Received:
    0
    Trophy Points:
    11
    Finally!

    So you snag a flash video file (.flv), convert it to your preferred video format, and the audio/video sync is off. Then you google the issue and spend hours reading and trying out various solutions.

    Demux. Framerate. Audio VBR. Re-mux. Audio is longer than video. Video is longer than audio. Adjust framerate. Adjust audio length.

    Nothing works, but you now have a vague clue as to what the problem is: the audio and video streams in the FLV have different lengths (or framerates or...), and when being converted one is being stretched to fit the other. Or something.

    Well, finally I figured out a solution. It's a longer process than I would like, but it works.

    First, I followed the basic instructions found here. (It's an offsite link but the best guide I've seen. If there's an equally as good guide here on the wonderful Afterdawn site let me know.)

    If we just followed that guide, you may still have A/V sync issues. I did. But there's an option in VirtualDubMod that fixed my sync issue!

    After you have the video and audio loaded, and Video set to Direct Stream Copy, select Video > Framerate and set to Change so video and audio durations match.

    That's it! My audio and video are now synced perfectly, and my long nightmare is over.

    BTW, the video(s) I was working with are from this site, grabbed with the nifty Replay Video Catcher.
  2. AfterDawn

    AfterDawn Advertisement

  3. jkonrad

    jkonrad Member

    Joined:
    Apr 29, 2008
    Messages:
    2
    Likes Received:
    0
    Trophy Points:
    11

    ... it also works to manually put in the framerate. In the case of the videos I mentioned above, 25.
  4. magge6

    magge6 Member

    Joined:
    Jun 4, 2008
    Messages:
    1
    Likes Received:
    0
    Trophy Points:
    11
    For doing all these procedure you can simply use media classic player to
    match audio and video. Also easy to preview and save.
  5. Tuskegee

    Tuskegee Member

    Joined:
    Jul 8, 2008
    Messages:
    2
    Likes Received:
    0
    Trophy Points:
    11
    I Love You
  6. abrogard

    abrogard Regular member

    Joined:
    Oct 18, 2002
    Messages:
    186
    Likes Received:
    0
    Trophy Points:
    26
    Yep, but mpc didn't save a corrected file that would work with VideoLan - it played out of sync again. But picking up the saved file with mpc again it played synced. Where this guide said it would always need correcting: http://pulse750.tripod.com/

    flvplayer also played (the corrected file) out of sync.

    But, yes, mpc plays it corrected every time I pick it up.

    I need it to be corrected for other software, too, because I need to edit the file. The freeware prog Flveditor Lite sees it as uncorrected, too - and isn't smart enough to correct it.

    So if anyone reads this thread again (it's three years old, I notice) and has some modern fix for this that i can use - please let me know.

    To get it straight what i want to do: sync an flv file so's I can extract a segment from it with an editor (flveditor lite).

    :)
    Last edited: Nov 17, 2011
  7. davexnet

    davexnet Active member

    Joined:
    Jul 7, 2003
    Messages:
    1,896
    Likes Received:
    0
    Trophy Points:
    66
    Not only that, creating a file with a non-standard frame rate may be
    problematic when played back on an external device. If it's only for viewing on
    the PC, it's usually OK (assuming it works at all).

    To get more directed advice, you need to provide an example of a file that has the
    problem, and more details of your work flow.

Share This Page