[FFmpeg-user] How to drop every Nth frame?

[Pavel Koshevoy]

On 9/28/13 4:16 AM, Andrey Aleksandrovich wrote:
>>>> How old is your build of ffmpeg?  There was an atempo sync bug
>>>> (http://trac.ffmpeg.org/ticket/2484), but that was fixed 5 months ago.
>>>> If you are able to reproduce a sync issue with current ffmpeg please
>>>> open a trac ticket.
> Yes, I think this is it.
> Version '1.2.3' - stable version at repositories of my system (Gentoo)
> 0.99667 = +7.3 sec desync
> 0.997 = +7.3
> 0.99834 = -3.3
> 0.99824 = -3.3
>
> And with latest 'N-56704-g3e0c78b' version I have:
> 0.99667 = +4.0
> 0.997 = +2.4
> 0.99834 = -4.9
> 0.99824 = -4.5
>
> So, seem like it is more accurate to decimals.Thanks for advise.
>

After the bug fix 5 months ago, you should expect atempo to stay in sync 
+/- 1 frame duration throughout.  An error of magnitude of 2..4 seconds 
is gigantic.  How did you arrive at the tempo scale factors that you've 
tried?  Do you know how long the track duration is and how long it 
should be?

     Pavel.