[FFmpeg-devel] [PATCH] libavfilter: vf_scale: Properly take in->color_range into account

[Michael Niedermayer]

On Sat, Mar 05, 2022 at 11:33:15PM +0200, Martin Storsjö wrote:
> On Fri, 4 Mar 2022, Michael Niedermayer wrote:
> 
> > On Thu, Mar 03, 2022 at 02:06:45PM +0200, Martin Storsjö wrote:
> > > While swscale can be reconfigured with sws_setColorspaceDetails,
> > > the in/out ranges also need to be set before calling
> > > sws_init_context, otherwise the initialization might choose
> > > fastpaths that don't take the ranges into account.
> > > 
> > > Therefore, look at in->color_range too, when deciding on whether
> > > the scaler needs to be reconfigured.
> > > 
> > > Add a new member variable for keeping track of this, for being
> > > able to differentiate between whether the scale filter parameter
> > > "in_range" has been set (which should override whatever the input
> > > frame has set) or whether it has been configured based on the
> > > latest frame (which should trigger reconfiguring the scaler if
> > > the input frame ranges change).
> > > 
> > > Signed-off-by: Martin Storsjö <martin at martin.st>
> > > ---
> > > To test this (without risking running many conflicting swscale
> > > filters in one filter pipeline), we'd need to be able to tag
> > > the incoming raw yuv data with colorspace and range without setting
> > > the in_color_matrix and in_range options on the scale filter.
> > > 
> > > When using the rawvideo demuxer, the pixel format is set via the
> > > ffmpeg -pix_fmt option, but there's no corresponding option for
> > > setting color matrix or range for it.
> > > ---
> > >  libavfilter/vf_scale.c | 13 +++++++++++++
> > >  1 file changed, 13 insertions(+)
> > 
> > This changes the output for:
> > ffmpeg -i tickets/524/AVCI50.mov   -vframes 3 file-avci50dec.nut
> > ffmpeg -i tickets/4493/AVCI100.mov -vframes 3 file-avci100dec.nut
> > 
> > https://samples.ffmpeg.org/ffmpeg-bugs/trac/ticket524/
> > 
> > Is that intended ?
> > 
> > - 233903 file-avci100dec.nut
> > - 383853 file-avci50dec.nut
> > + 196558 file-avci100dec.nut
> > + 333893 file-avci50dec.nut
> 
> Looks like these source files have full range content; for any data with
> full range input, this patch makes sure it uses the right intended
> conversion through swscale. So yes, I guess it's expected that these
> conversions change.

patch ok then

thx

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

I have never wished to cater to the crowd; for what I know they do not
approve, and what they approve I do not know. -- Epicurus
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