[FFmpeg-devel] [PATCH v2] avfilter/vf_showinfo: Fix erroneous results for mean and stdev with pixel bits >8

Limin Wang lance.lmwang at gmail.com
Tue Dec 3 16:25:30 EET 2019


On Thu, Nov 28, 2019 at 11:51:13PM +0100, Michael Niedermayer wrote:
> On Thu, Nov 28, 2019 at 10:34:41PM +0800, lance.lmwang at gmail.com wrote:
> > From: Limin Wang <lance.lmwang at gmail.com>
> > 
> > The following is one of the testing results, you can observe the result of 16bit isn't correct.
> > 1, yuv420p
> > ./ffmpeg -f lavfi  -i color=black:duration=1:r=1:size=1280x720,format=yuv420p,showinfo
> > Master:
> > mean:[16 128 128] stdev:[0.0 0.0 0.0]
> > After applied the patch:
> >  mean:[16 128 128] stdev:[0.0 0.0 0.0]
> > 
> 
> > 2, yuv420p10
> > ./ffmpeg -f lavfi  -i color=black:duration=1:r=1:size=1280x720,format=yuv420p10,showinfo
> > Master:
> > mean:[32 1 1] stdev:[32.0 1.0 1.0]
> > After applied the patch:
> > mean:[64 512 512] stdev:[0.0 0.0 0.0]
> 
> with >8bit, both little and big endian formats should be tested

Michael, I have updated the patch and test with le and be formats on be
and le system. Please review whether the test is complete.

> 
> thx
> 
> [...]
> -- 
> Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
> 
> Frequently ignored answer#1 FFmpeg bugs should be sent to our bugtracker. User
> questions about the command line tools should be sent to the ffmpeg-user ML.
> And questions about how to use libav* should be sent to the libav-user ML.



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