[FFmpeg-devel] [PATCH 8/8] avcodec/decode: copy the output parameters from the last bsf in the chain back to the AVCodecContext

[Michael Niedermayer]

On Fri, Jul 27, 2018 at 11:11:47PM -0300, James Almer wrote:
> On 7/27/2018 10:58 PM, Michael Niedermayer wrote:
> > On Fri, Jul 27, 2018 at 11:57:49AM -0300, James Almer wrote:
> >> Certain AVCodecParameters, like the contents of the extradata, may be changed
> >> by the init() function of any of the bitstream filters in the chain.
> >>
> >> Signed-off-by: James Almer <jamrial at gmail.com>
> >> ---
> >> Now it's not going to be called after the codec has been opened.
> >>
> >>  libavcodec/decode.c | 4 ++++
> >>  1 file changed, 4 insertions(+)
> > 
> > This breaks:
> > ffmpeg -i https://upload.wikimedia.org/wikipedia/commons/1/14/Animated_PNG_example_bouncing_beach_ball.png -bitexact -pix_fmt rgba -f framecrc -
> 
> Is any other decoder failing the same way? Because the apng decoder
> threading code may be faulty otherwise. Plenty of avctx fields are
> changed after ff_thread_init() is called within avcodec_open2(). There
> should not be a race at this point.

I found a failure with mpeg4 (with bframes) decoding + pcm_alaw from mkv but it
does not want to reproduce. The slightest change i do makes this not happen
even just duplicating a command line parameter (which should have no effect)
simply adding the -threads parameter to it independant of value makes it go away
too


in the png case
this hits teh issue:
-threads 2 -i https://upload.wikimedia.org/wikipedia/commons/1/14/Animated_PNG_example_bouncing_beach_ball.png  -f framecrc -

this does not:
-threads 1 -i https://upload.wikimedia.org/wikipedia/commons/1/14/Animated_PNG_example_bouncing_beach_ball.png  -f framecrc -

also odly the bitexact flag made a differnce in how it fails outside valgrind
last i tried. (doesnt make a difference in valgrind it seems)

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

If you think the mosad wants you dead since a long time then you are either
wrong or dead since a long time.
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