[FFmpeg-devel] Question about frame->pts, outlink->time_base, and outlink->frame_rate

Nicholas Robbins nickrobbins at yahoo.com
Wed Jan 29 12:48:02 CET 2014

> On Tuesday, January 28, 2014 7:34 PM, Andrey Utkin <andrey.krieger.utkin at gmail.com> wrote:

> > 2014-01-29 Nicholas Robbins <nickrobbins at yahoo.com>:
>>  If I could just multiply the time_base by 1/8 I would have no rounding in 
> the filter.
>>>  Which media container type do
>>>  you use, and are you able to use another if it fits better?
>>  I plan on using libx264 in matroska, but in terms of testing and 
> understanding I could use something different.
>>  I've written the patch already and its behavior is about 99% of what I 
> want, so if getting that last 1% is not worth it, I'm fine with that, but I 
> want to make sure what I think is happening is in fact happening.
> Is that right that you run your filter using ffmpeg command line utility?

> There is an AVCodecContext AVOption "time_base", but currently it is
> not managable through command line, although it can be enabled for
> that with a patch
> diff --git a/libavcodec/options_table.h b/libavcodec/options_table.h
> index c82c104..89c30fc 100644
> --- a/libavcodec/options_table.h
> I am not sure whether it is a bug or design.
> I've done so, and output file of a command
> ffmpeg -re -f lavfi -i testsrc  -vcodec libx264 -time_base 1/10000  /tmp/tmp.mkv
> Maybe you could try this way and tell us whether it helps you.
> -- 
> Andrey Utkin

That option doesn't seem to change the PTS's of the packets.

Nicholas Robbins

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