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  1. hi there,
    i am trying to sync an audio file of the avi movie to its video in virtualdub

    audio of the movie is taken from another video source of the same movie

    video info:
    length: 2:27:36.13
    bit rate:930 kbps

    audio info:
    original length:2:37:26.952
    changed length:2:27:08.92(length changed using avs audio editor using tempo effect)
    bit rate:320 kbps

    i am trying to sync this audio in the video with a delay of approx 10 seconds ,but with no success

    please tell me the steps to properly syns the audio to video through entire length of video
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  2. Member Budman1's Avatar
    Join Date: Jul 2012
    Location: NORTHWEST ILLINOIS, USA
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    If you just want to delay the audio with VirtualDub, select Audio -> Interleaving and set the delay in Milliseconds (10000 for 10 seconds).
    Otherwise FFmpeg will do a quick job of it with:
    FFMpeg -i video.avi -itsoffset 10 -i audio.xxx -map 0:0 -map 1:0 -vcodec copy -acodec copy output.avi

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    Last edited by Budman1; 6th Apr 2014 at 09:38. Reason: spacing problem in script
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  3. thanks for replying

    i have done the same in vdub,but it works for a few seconds of the video
    and then audio gets out of sync
    is there anyting else to be done

    please help
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  4. Member
    Join Date: Jun 2012
    Location: USA
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    It seems like you're making some very big assumptions,

    Are you certain that you have tempo effected the audio properly? How did you determine that?
    Are you certain the start delay should be exactly 10 seconds? How did you determine that?
    Are you certain the video and audio are the same version of the film, no scenes have been added deleted, lengthened or shortened? How did you determine that?

    If all of these things are not true, you will not maintain sync for two and a half hours.
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  5. Mod Neophyte Super Moderator redwudz's Avatar
    Join Date: Sep 2002
    Location: AZ, USA
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    If the audio sync gradually gets worse, usually the audio length is different. With your video, it may be the audio is not the same as the original audio and may have several parts that differ. If that's true, very difficult to fix.

    Or, you may have done your 'adjustments' backwards. Maybe you need to change the offset first, then adjust the 'tempo' length. The common problem with differing audio lengths is sometimes caused by the video creator adding a short piece of video, such as an intro, to the beginning of the video track before the audio starts. The other audio track may be from a video that doesn't have this.

    Ten minutes is a huge difference in audio/video lengths. I think one of your audio/video tracks has been heavily edited.

    One method I have used is to play the video with a player like Media Player Classic. It has a sync adjustment. Note the offset when you get the audio in sync and use that number to set the offset in your editor.
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  6. hi guys thanks for replaying,
    ok let me explain:
    as i have mention that i changed audio length with tempo effect in avs audio editor
    the avs audio editor shows the length of the audio after processing it,which i have mentioned as changed length
    second thing is that before the audio plays in the movie,the intro part(which shows the date of release etc) of the movie plays for approx 10 seconds
    so what i did, i got a copy of the movie which did not had intro part(10 seconds part) in it,i extracted its audio and used tempo effect to changed its length as mentioned above
    then i tried to sync it in the movie which has intro part of approx 10 secs with a delay of approx 10 secs
    this movie had some audio cut for 2-3 secs in the later part,thts why i used audio of other version(copy) of the movie where audio was ok

    i think i am able to explain yu guys
    if there is any solution to it,then tell me

    i am doing this because the movie in which i want to sync audio,it has russian voice over, over hindi(there is only one audio stream)
    i cannot get rid of the russian voice over

    thanks
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  7. Member
    Join Date: Jun 2012
    Location: USA
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    You're not going to get there by guesswork. You're going to have to lay the two different audio versions next to each other in something like audacity,

    1. find an exact sync point near the beginniing.
    2. Play it down to determine if there is consistent drift,
    3. measure that drift in terms of frames per second, or per minute. (If there is no drift, go to 7.)
    4. Adjust the speed with your tempo tool (which does not sound particulary accurate) or in Audacity (which can be very accurate.)
    5. Start again at a known sync point near the beginning
    6. Check again for drift. (If there is still drift go back to 3.)
    7. Play it down until you encounter a difference.
    8. Adjust the difference by cutting or adding time to the modified audio.

    When done, mux the new audio with the original video.
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  8. Member
    Join Date: Mar 2008
    Location: United States
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    Originally Posted by pappubeta View Post
    i think i am able to explain yu guys
    if there is any solution to it,then tell me
    Of course there's a solution, unless the assets are from two different cuts of the movie.
    You have to look at it logically and think about what you're doing.

    Regarding the 10 seconds missing at the start, ,might be better to add 10 seconds to the file at the beginning to make it
    a closer match when you open it in Virtualdub. You can do this in the audio editor.
    Save the new audio as a file on the desktop. Open the video without any audio
    in virtualdub. Select audio/audio from other file.. Load the new audio and check from some lip movement at the beginning,
    how close it is. Then look for scenes in the middle and end and check there too.

    If they are out the same amount, you can use audio/interleave to shift the whole audio either earlier or later.

    If the audio gets further out along the movie, you can shrink/expand the file in the audio editor by a small amount and retry the operation.
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  9. thanks thanks thanks
    i will try


    thanks
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  10. Mod Neophyte Super Moderator redwudz's Avatar
    Join Date: Sep 2002
    Location: AZ, USA
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    Your first post said:

    .....video info:
    ....length:2:27:36.13


    ....audio info:
    ....original length:2:37:26.952

    Is that a typo? That says 10 MINUTES difference??
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  11. There's no guarantee two versions of the same video are the same. In a perfect world, the NTSC and PAL versions of a movie (for example) would have the same number of frames and they'd just play at slightly different speeds. In the real world though, they're often edited slightly differently. Sometimes it's just a frame less in one scene here, a second more there..... so there's no way to sync the audio of one with the other properly simply by stretching it. Even DVD and Bluray versions can be edited slightly differently.

    I find it's best to assume they won't sync, then if they do it's a pleasant surprise. Assuming they will sync can often lead to disappointment.
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  12. Member
    Join Date: Feb 2004
    Location: Australia
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    Solve this problem using aviutil

    Some of the suggestions have followed the common methods however you have not told use how the sync problem is shown.

    If this is in vdub, any version, they all have an issue with retaining any sync in problematic files no matter how you adjust it so don't use it for this purpose.

    Go back to the original audio.

    In aviutil add the video / audio source, align starting positions so it's in sync.

    Play till sync issue, split audio just before this point and move the remaining audio to next track, repeat

    Where audio snips overlap apply tempo adjust to reduce audio snippet length one at a time as you go forward.

    This would allow background noise's to retain sync

    Any excess beyond the video time should be clipped and deleted.

    So you now end up with streams of matching length, in sync, no problems with background audio.
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