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Unofficial VirtualDub Support Forums > Codec Discussion > Bug?: Mp3-audio Is ~50ms Longer Than Video


Posted by: Burg Mar 14 2009, 06:29 PM
Hi,

when re-encoding the video & audio (to MP3), the audio track is always some 40-50 milliseconds longer than the video track (determined through File > File Information). When joining some 20 clips, this adds up to a noticeable audio delay :-(
I've tried it with VirtualDub's own MP3 codec, and with Lame ACM.
This problem is not occurring when using AC3, WMA1/2 or PCM (raw) audio. Does anybody have any suggestions? Or just use another audio codec?

Cheers!

Posted by: chornobyl Mar 16 2009, 03:35 PM
http://lame.sourceforge.net/tech-FAQ.txt

http://en.wikipedia.org/wiki/Gapless_playback

Posted by: Dstruct Mar 20 2009, 06:18 AM
Which audio codec coud be used which doesn't have this problem?


Ogg Vorbis doesn't work with AVI files right?

Posted by: chornobyl Mar 20 2009, 10:12 AM
I remember Vorbis-acm worked fine for me in avi container.

Posted by: Dstruct Mar 20 2009, 10:22 AM
And where to find a up-to-date Vorbis ACM codec (built on libVorbis 1.2.0)? Couldn't find one sad.gif

Posted by: Burg Mar 21 2009, 03:59 PM
Let me summarize:

*chornobyl (sort of) suggested to use Lame with the --nores setting. I started a new thread about this: http://forums.virtualdub.org/index.php?act=ST&f=3&t=17014

* I've tested the Vorbis Ogg ACM Codec 1.0. Result: The length difference is even worse than with MP3 :-(

* So far, I found only two methods which result in exactly the same audio+video length:
o uncompressed PCM :-)
o IMA ADPCM - what is this? Anybody any experiences?

* What about WMA? I've installed the Windows Media Encoder 9, but I think I don't get all options (i.e. high quality) in VirtualDub? Shouldn't there be a lossless version of WMA too ("Windows Media Audio Lossless")?

Thanks!!

Posted by: stephanV Mar 21 2009, 08:00 PM
The easiest solution would be to wait with compressing the audio till all the files are joined.

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