[FFmpeg-user] Concat videos properly (without dropped or freezed frames)

kwi wi qui.after at gmail.com
Wed Mar 6 22:31:59 CET 2013

Right, I've tried specifying the frame rate and it kind of works but then
it seems like there is much more freezing going on.
I guess I'll have to settle for that since the videos can be choppy (due to
vfr) at times.

Can I ask why the MP4 format is not a good choice for this type of

Also, what resources would you recommend to get familiar with transcoding?
Especially with respect to performing it with ffmpeg?

On Wed, Mar 6, 2013 at 2:43 PM, Nicolas George <
nicolas.george at normalesup.org> wrote:

> Le sextidi 16 ventôse, an CCXXI, Nicolas George a écrit :
> > Yes, these messages seem to indicate a real problem, but I do not know
> what
> > yet.
> Ok, got it.
> The core of your problem is that your 3GP file have random frame rates.
> When
> converting to MP4, ffmpeg takes a best guess for the frame rate of the file
> (the ffmpeg MP4 muxer does not support variable frame rate), and not the
> same for each file.
> The concat demuxer can support variable frame rate, but it currently
> requires that all files have the same time base for the corresponding
> files.
> You can fix the problem by supplying a -r option to your 3GP -> MP4
> conversions, with the same value each time.
> Moving away from the MP4 format is always a good idea too.
> Regards,
> --
>   Nicolas George
> Version: GnuPG v1.4.12 (GNU/Linux)
> dWUAn10biUGN3jC0LTvV0gNBxQCuoWUK
> =ijRf
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