[FFmpeg-user] Help: transform 'asyncts=first_pts=0' into new 'aresample' filter

Carl Eugen Hoyos cehoyos at ag.or.at
Sun Feb 3 00:01:20 CET 2013

Frank Häfemeier <ffmpeg <at> frank.haefemeier.eu> writes:

> The sample itself is in sync, but after converting it into h.264/aac in
> mp4 container the audio is out of sync. You can see and hear it if you
> are around 20s when you see people talk.
> As I currently understand, the first approx. 0.30s are the problem,
> because I found out during my tests (to get the sample), if you skip the
> first 0.40s or so (using -ss 00:00:00.40 after -i parameter) the audio
> is in sync without using a filter.
> 30s video sample:
> http://www.datafilehost.com/download-c12482c8.html

I tested the following command lines:
$ ffmpeg -async 1 -i video-sample.ts -qscale 2 out.avi
$ ffmpeg -async 1 -i video-sample.ts -qscale 2 -vcodec mpeg4 -strict -2 out.mov

Both out.avi and out.mov play in-sync, both when encoded 
with current FFmpeg and an older version.

Thank you for the sample, Carl Eugen

More information about the ffmpeg-user mailing list