[FFmpeg-devel] [PATCH] lavfi: add duration field to AVFilterBufferRef
michaelni at gmx.at
Tue Jul 31 15:53:19 CEST 2012
On Mon, Jul 30, 2012 at 07:20:32PM +0200, Nicolas George wrote:
> Le tridi 13 thermidor, an CCXX, Stefano Sabatini a écrit :
> > ---
> > libavfilter/audio.c | 1 +
> > libavfilter/avcodec.c | 2 ++
> > libavfilter/avfilter.h | 7 +++++++
> > libavfilter/buffer.c | 1 +
> > libavfilter/f_settb.c | 10 ++++++----
> > libavfilter/vf_showinfo.c | 6 ++++--
> > 6 files changed, 21 insertions(+), 6 deletions(-)
> I must say, after some thought since last time it was suggested, I am not
> completely sure it is such a good idea.
duration is neccessary for low latency frame rate changing filters.
i think the filter framework would be a joke if it couldnt do that.
> What happens with filters such as select? Is it supposed to wait for the
> next accepted frame in order to adjust the duration?
not really relevant.
select can set duration = N/A, thats just what it does ATM
improving select beyond that becomes possible if duration is available
also its easy to add a flag to inputs that says need_duration and let
the avfilter core then buffer one frame to get the duration if its
> And what if the duration and the next timestamp are inconsistent?
undefined behavior and there could be a filter that corrects such
inconsistencies in a consistent way
> This is not an easy issue.
no but IMHO not adding information because its too hard to use it in all
cases is the worse.
A filter can alway just not look at a field if it doesnt want to
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
Old school: Use the lowest level language in which you can solve the problem
New school: Use the highest level language in which the latest supercomputer
can solve the problem without the user falling asleep waiting.
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