[Ffmpeg-devel] [PATCH] fix frame duration computation in find_stream_infos

[Michael Niedermayer]

Hi

On Tue, Mar 27, 2007 at 12:47:19PM +0200, Baptiste Coudurier wrote:
> Hi
> 
> Michael Niedermayer wrote:
> > Hi
> > 
> > On Fri, Mar 09, 2007 at 11:34:08PM +0100, Baptiste Coudurier wrote:
> >> Michael Niedermayer wrote:
> >>> Hi
> >>>
> >>> On Fri, Mar 09, 2007 at 09:51:44PM +0100, Baptiste Coudurier wrote:
> >>>> Hi
> >>>>
> >>>> Michael Niedermayer wrote:
> >>>>> Hi
> >>>>>
> >>>>> On Fri, Mar 09, 2007 at 05:42:48PM +0100, Baptiste Coudurier wrote:
> >>>>>> Hi
> >>>>>>
> >>>>>> $subj.
> >>>>>>
> >>>>>> I guess there is a typo here. Is it correct ?
> >>>>>> last_dts should be updated when duration is present.
> >>>>> no its no typo, this improves accuracy IIRC
> >>>>>
> >>>> ok, I misunderstood the code then.
> >>>>
> >>>> wrong_frame_rate.mp4 in incoming:
> >>>> Stream #0.0(eng): Video: mpeg4, yuv420p, 352x288, 49.67 fps(r)
> >>>>
> >>>> should be 16.38 (quicktime),
> >>> just because QT says it, doesnt make it correct ...
> >> well, just because ffmpeg says it, neither.
> > 
> > of course not, the real_frame_rate thing is just a guess and the
> > doxy says so IIRC
> > 
> > 
> >>> 16.38 does not look like a likely framerate at all
> >> 49.67 neither.
> > 
> > of course, 49.67 is nonsense
> > 
> 
> I was still thinking about this issue, and since mov demuxer knows all
> durations/timestamps after read_header, should it set r_frame_rate to
> the correct value ? How would you see it ? I don't really get
> r_frame_rate meaning since it is meant to be exact, but only take a few
> durations into account.

hmm, setting r_frame_rate in a demuxer might be an option but ONLY if its
set correctly


> 
> like total_frames * timescale, total_duration ? But that seems to be
> average frame rate.

NO r_frame_rate is not the average framerate

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

it is not once nor twice but times without number that the same ideas make
their appearance in the world. -- Aristotle
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