On Mon, Mar 26, 2018 at 10:56:47PM +0100, Mark Thompson wrote:
> On 26/03/18 22:44, Michael Niedermayer wrote:
> > On Mon, Mar 26, 2018 at 08:34:06AM +0200, Paul B Mahol wrote:
> >> On 3/26/18, Michael Niedermayer <mich...@niedermayer.cc> wrote:
> >>> On Wed, Mar 21, 2018 at 09:18:21AM +0100, Paul B Mahol wrote:
> >>>> On 3/20/18, Michael Niedermayer <mich...@niedermayer.cc> wrote:
> >>>>> Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc>
> >>>>> ---
> >>>>> libavfilter/vf_scale.c | 7 ++++++-
> >>>>> 1 file changed, 6 insertions(+), 1 deletion(-)
> >>>>>
> >>>>> diff --git a/libavfilter/vf_scale.c b/libavfilter/vf_scale.c
> >>>>> index 9f45032e85..2f6fa4791d 100644
> >>>>> --- a/libavfilter/vf_scale.c
> >>>>> +++ b/libavfilter/vf_scale.c
> >>>>> @@ -407,6 +407,7 @@ static int filter_frame(AVFilterLink *link, AVFrame
> >>>>> *in)
> >>>>> AVFilterLink *outlink = link->dst->outputs[0];
> >>>>> AVFrame *out;
> >>>>> const AVPixFmtDescriptor *desc =
> >>>>> av_pix_fmt_desc_get(link->format);
> >>>>> + const AVPixFmtDescriptor *out_desc =
> >>>>> av_pix_fmt_desc_get(outlink->format);
> >>>>> char buf[32];
> >>>>> int in_range;
> >>>>>
> >>>>> @@ -497,7 +498,11 @@ static int filter_frame(AVFilterLink *link,
> >>>>> AVFrame
> >>>>> *in)
> >>>>> table, out_full,
> >>>>> brightness, contrast,
> >>>>> saturation);
> >>>>>
> >>>>> - out->color_range = out_full ? AVCOL_RANGE_JPEG :
> >>>>> AVCOL_RANGE_MPEG;
> >>>>> + // color_range describes YUV, it is undefined for RGB
> >>>>> + if ((out_desc->flags & AV_PIX_FMT_FLAG_RGB) &&
> >>>>> out_desc->nb_components != 1) {
> >>>>> + out->color_range = AVCOL_RANGE_UNSPECIFIED;
> >>>>> + } else
> >>>>> + out->color_range = out_full ? AVCOL_RANGE_JPEG :
> >>>>> AVCOL_RANGE_MPEG;
> >>>>> }
> >>>>>
> >>>>> av_reduce(&out->sample_aspect_ratio.num,
> >>>>> &out->sample_aspect_ratio.den,
> >>>>> --
> >>>>> 2.16.2
> >>>>>
> >>>>
> >>>> This is not optimal, as full color_range should remain full when not
> >>>> changed.
> >>>
> >>> there is no range for rgb formats. The range is specific to YUV based
> >>> formats.
> >>> Thats, if iam guessing correctly what you meant. You did not really say
> >>> which case you meant here. So maybe there is an issue and i misunderstand
> >>> what you refer to
> >>
> >> Maybe not for swscale here but does exist otherwise.
> >
> > It has no meaning for RGB. There is no limited range RGB
> > also, the API defines it only for YUV. So if it had meaning for RGB its not
> > defined
> > what meaning that would be. The ranges for luma and chroma differ so its not
> > natural or obvious how to extend it to RGB.
> > Iam also not aware of any specification that defines limited range RGB
> See HDMI, HD-SDI, CEA-861, pretty much anything related to sending RGB over
> wires in a non-PC context.
>
> (No comment on whether it is useful to include it, but dismissing limited
> range RGB as not a thing is probably not a good idea. I would kindof expect
> things like DeckLink to be using limited-range RGB everywhere, but I'm not
> familiar with the details there.)Is this used just over wires or also in software ? aka should we update our enum to also cover this and If yes then we also probably should add support for this to swscale thx [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB No human being will ever know the Truth, for even if they happen to say it by chance, they would not even known they had done so. -- Xenophanes
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