[FFmpeg-user] FLV --> MP4 Conversion Audio/Video Out of Sync

bat guano batguano999 at hotmail.com
Mon Dec 24 00:02:58 CET 2012

> I converted it to an MP4 using the command:
> ffmpeg -i telecomcto.flv -c:v copy -c:a aac -strict -2 -b:a 64k -ar 44100
> -ac 1 telecomctotest.mp4
>  I have not figured out how to get the audio to be in sync with the video.

I think your problem is caused because the flv file is variable *frame* rate.
Maybe it's not possible to maintain video/audio sync unless you convert the video track as well as the audio track.
Though perhaps somebody else will have a better idea.

This is the command I've used.
(note that "-vsync 1 -r 25" forces the result to "constant" frame rate 25fps)

ffmpeg -i telecomcto.flv -c:v libx264 -crf 23 -preset medium -vsync 1 -r 25 -c:a aac -strict -2 -b:a 64k -ar 44100 -ac 1 Xtelecomctotest.mp4

Result is here ---> http://www.mediafire.com/?0iupb3rve5680x0

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