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  1. Member
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    I have searched the forums for a while now, and have not found a description of the problem I am having. Here is the issue:
    I have an avi file that starts off synced perfectly, but after a while, the audio gets out of sync.

    Here is the weird thing: if you jump to a place later in the video, the audio will be right on. It only gets out of sync when you play it straight.

    I loaded it into Gspot, but I can't figure out how to export the results.
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  2. I'm a MEGA Super Moderator Baldrick's Avatar
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    Take a screenshot from gspot using the prt-scrn-key and paste into paint, save as jpg and post in our forum.

    Try play with VLC media player and see if it works better, if it does you probably have some video or audio codecs problems.
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    I have played it in VLC. It behaves the same way. Also does this in Nero Showtime. I have muxed the audio to wav using virtual dub, and muxed out just the video as well.

    I have played the file using hypercube time stretcher (video w/o audio and wav are seperate inputs) and the audio matches perfectly while watching it this way. So an uneducated guess says my directshow codecs are messed up? Maybe not. I humbly seek your extremely informed opinions.

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    I had tried to dub it with virtualdub. step one, save the .wav file from the original, then dub using that wav, recompressing it. but when I did, the highest audio compression I could choose was 58kBits/s which is very low compared to the 128 of the original. Is that because virtualdub doesn't support higher compression for mpeg layer-3? Also, afterwards it still had the same problem.
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    Another question I have is what effect would the codecs have when I am re-encoding video to a different format? (like mp4 for ipod)
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  6. Member Soopafresh's Avatar
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    Try running it through this. Minimally, it will reindex the file and add CBR audio.

    https://forum.videohelp.com/topic314909.html

    Use Avi_Gain_Regular.bat
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    It sounds like a file that was fixed incorrectly and recompressed back to VBR.

    You can try using Goldwave (or similar audio editor) to stretch the audio to match the video. If the audio is longer than the video then you're probably out of luck.

    As for the 56kbs audio here's a thread from the VDub forums pertaining to the issue...

    http://forums.virtualdub.org/index.php?act=ST&f=3&t=8005&s=6c0bfe13bec616b5b67e2974041a7b3f

    The new experimental version of Virtualdub 1.7.X test 3 will handle VBR MP3 without having to do anything to the audio but if it was converted incorrectly to begin with, I doubt it will help unless you stretch the audio to match the video.
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  8. Mod Neophyte Super Moderator redwudz's Avatar
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    Is that because virtualdub doesn't support higher compression for mpeg layer-3?
    That's not VD's fault.
    That's because it's using the default MP3 system codec. Install Lame MP3 ACM and you will have many more choices for MP3 encoding.

    EDIT:
    if you jump to a place later in the video, the audio will be right on. It only gets out of sync when you play it straight.
    I've seen that behavior a few times when the video is being processed slower than the audio and is being buffered. Then when you pause or jump forward, it goes back in sync. If this were happening, the audio should be ahead of the video. You would also likely get high CPU usage percents.

    But more likely it's something wrong with the file. VLC uses it's own codecs, so not likely it's a codec problem.
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  9. Member
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    I've seen that behavior a few times when the video is being processed slower than the audio and is being buffered. Then when you pause or jump forward, it goes back in sync. If this were happening, the audio should be ahead of the video. You would also likely get high CPU usage percents.

    But more likely it's something wrong with the file. VLC uses it's own codecs, so not likely it's a codec problem.
    So what is wrong with the file in that case? How would I go about fixing it?
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