[FFmpeg-devel] video corruption using h264 hw decoders

Michael Niedermayer michaelni at gmx.at
Wed Nov 23 14:26:59 CET 2011

On Sun, Nov 06, 2011 at 01:24:59AM +0100, Joakim Plate wrote:
> On Thu, 3 Nov 2011 16:22:23 +0100, Michael Niedermayer wrote:
> > On Thu, Nov 03, 2011 at 12:13:07AM +0100, Joakim Plate wrote:
> >> [25 quoted lines suppressed]
> > 
> > iam not against it if it works but it leaves ambiguity for the left
> > and top crop
> > 
> > 
> > [...]
> So here's the patch. As you say it does leave an ambuigity for left/top
> crop. But that was there before too. Exposing crop using pan_scan could be
> an option, but could potentially break compatibility.
> pan_scan does have a somewhat different meaning, even if it does fit the
> bill rather nicely.
> There is one issue with this patch. It doesn't detect changes in crop
> values during playback. I'm not sure that matters too much thou seing as
> cropping is not fully handled anyway. Also flushing all reference frames on
> crop changes seem wrong as well.
> fate passes, and i've not seen any odd behaviour in the samples i've tried.

this patch causes an interresting issue.
when the decoder is closed and opened again the
avcodec_set_dimensions() calls in avcodec_open2() change the width
which ends up causing ffprobe and ffmpeg to print differing widths
for  http://panda-test-harness-videos.s3.amazonaws.com/panda.mp4

[... ]

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

There will always be a question for which you do not know the correct awnser.
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