Fixing audio sync in .MP4 file?

[Anakunda]

Hello, I need to set audio delay in existing MP4 video file.
Is that possible that I remux with delay parameter at audio track?
If I look at MP4Box options, there's -delay allowing this so I assume MP4 format supports delay at track levels.
Now the question is how do I simply remux with either MP4Box or other utility with original MP4 file as input. Or worse, to fully demux all tracks from MP4 fille including subtitles and compose from scratch. I got not too familiar with MP4Box switches, any help?

[b66pak]

you can use mp4fpsmod (http://forum.doom9.org/showthread.php?t=161386)...

mp4fpsmod -d yourdelay -c -o out.mp4 in.mp4
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[Anakunda]

Thanks,, I'll give a try. I need to apply individual delay for each track (2 audio tracks)3

[b66pak]

same delay will be applied to all audio tracks...but if you need individual delay for each track is better to correct this before muxing (eac3to is a very good tool for this)...
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[Anakunda]

but if you need individual delay for each track is better to correct this before muxing
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So bad I don't have the bare tracks anymore. Any chance to demux mp4 completely?

[Lyle_JP]

So bad I don't have the bare tracks anymore. Any chance to demux mp4 completely?

Hmmm, I sense a Rule 6 smiting in your future. Demuxing an mp4 into raw tracks is easy. Just use mp4box or any of its derivatives or front-ends (like Yamb).