[FFmpeg-user] How to fix audio/video out of sync problem

[Carl Eugen Hoyos]

肖谋 <xiaomou <at> gmail.com> writes:

> I have a mp4 file 1.mp4 in which the audio is about 
> 2 seconds ahead of video. I want to fix this using 
> ffmpeg without transcoding, just copy.

-itsoffset may help:
$ ffmpeg -i 1.mp4 -itsoffset 2 -i 1.mp4 -codec copy -map 0:0 -map 1:1 2.mp4

You may have to move the itsoffset (and change between 2 and -2).

Carl Eugen