[FFmpeg-devel] [PATCH] swscale/utils: Remove bpc==8 gating init_range_convert

Michael Niedermayer michael at niedermayer.cc
Thu Nov 30 19:52:33 EET 2017


On Wed, Nov 29, 2017 at 08:08:40PM -0800, Neil Birkbeck wrote:
> On Wed, Nov 29, 2017 at 7:40 PM, Neil Birkbeck <neil.birkbeck at gmail.com>
> wrote:
> 
> >
> >>
> >> If you are searching for a case where the patch makes a difference
> >> one is:
> >> ./ffmpeg -i ~/tickets/4493/AVCI100.mov out.nut
> >> file should be here:
> >> http://samples.ffmpeg.org/ffmpeg-bugs/trac/ticket524/
> >>
> >> if you want more cases that change, ill see if i can find more
> >>
> >
> > Perfect, thanks Michael. Let me check those samples out.

there are 2 more in 2939 which change:
https://trac.ffmpeg.org/ticket/2939


> >
> >
> For that sample, I feel like it may be incorrectly tagged as pc/full.

is it stored in the file or taken from:
ff_generate_avci_extradata()
maybe theres a bug in the AVCIntra handling



> Looking at the histogram of the original there is no data in low range and
> a peak due to clipping near where you'd expect higher up for studio/mpeg
> range
> ffplay /tmp/AVCI100.mov -vf histogram
> 
> And scaling, treating the input as studio/mpeg and outputting full range,
> stretches y to cover the entire range:
> ffplay /tmp/AVCI100.mov -vf
> scale=-1:-1:in_range=mpeg:out_range=jpeg,format=yuv422p10le,histogram
> 
> This is a real concern though. I don't have a good feel for how many higher
> bit depth files are incorrectly labelled as pc/full.
> 
> Here is a comparison of what I was described in the commit log.
> >
> > The naming of the files images are ${pixfmt}_${scaled}_${in_range}_${out_range}
> > for with/without the patch:
> > https://rawgit.com/nbirkbeck/ffmpeg-test-samples/master/
> > color-range/results/report.html
> >
> > My concern was the yuv444p10_${scaled}_jpeg_mpeg (explicit settings), give
> > different results than the implicit yuv444p10_unscaled_unspec_mpeg ones for
> > high bit depth. And the high bit depth is results are in general different
> > than the low bit depth ones.
> >

> > Report generated with:
> > https://raw.githubusercontent.com/nbirkbeck/ffmpeg-test-
> > samples/master/color-range/run.sh

Can you turn this into a fate test ?


> > Using these test files:
> > https://github.com/nbirkbeck/ffmpeg-test-samples/tree/
> > master/color-range/data
> >
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel at ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

When you are offended at any man's fault, turn to yourself and study your
own failings. Then you will forget your anger. -- Epictetus
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 181 bytes
Desc: Digital signature
URL: <http://ffmpeg.org/pipermail/ffmpeg-devel/attachments/20171130/eb2f9f6a/attachment.sig>


More information about the ffmpeg-devel mailing list