[FFmpeg-devel] [PATCH 12/24] avcodec/mjpegenc: add support for non-YUVJ formats

[Rostislav Pehlivanov]

On 2 May 2018 at 19:46, wm4 <nfxjfg at googlemail.com> wrote:

> On Wed, 2 May 2018 19:37:27 +0100
> Rostislav Pehlivanov <atomnuker at gmail.com> wrote:
>
> > On 2 May 2018 at 19:16, wm4 <nfxjfg at googlemail.com> wrote:
> >
> > > On Wed, 2 May 2018 19:14:21 +0100
> > > Rostislav Pehlivanov <atomnuker at gmail.com> wrote:
> > >
> > > > On 2 May 2018 at 19:04, Marton Balint <cus at passwd.hu> wrote:
> > > >
> > > > >
> > > > >
> > > > > On Tue, 1 May 2018, Rostislav Pehlivanov wrote:
> > > > >
> > > > > On 1 May 2018 at 23:22, Paul B Mahol <onemda at gmail.com> wrote:
> > > > >>
> > > > >> On 5/2/18, Michael Niedermayer <michael at niedermayer.cc> wrote:
> > > > >>> > Hi
> > > > >>> >
> > > > >>> > On Tue, May 01, 2018 at 09:40:01PM +0200, Paul B Mahol wrote:
> > > > >>> >> Signed-off-by: Paul B Mahol <onemda at gmail.com>
> > > > >>> >> ---
> > > > >>> >>  libavcodec/mjpegenc.c      | 5 ++++-
> > > > >>> >>  libavcodec/mpegvideo_enc.c | 3 +--
> > > > >>> >>  tests/lavf-regression.sh   | 2 +-
> > > > >>> >>  3 files changed, 6 insertions(+), 4 deletions(-)
> > > > >>> >
> > > > >>> > This doesnt work
> > > > >>>
> > > > >>> It does work, if you want full range set full range as option.
> > > > >>> Check visually colors.
> > > > >>> This happens because rgb is still marked incorrectly as limited
> > > range,
> > > > >>> so limited is picked instead.
> > > > >>>
> > > > >>>
> > > > >> Shouldn't this be part of the patchset?
> > > > >>
> > > > >
> > > > > I thought that color_range only matters for YUV formats, for RGB
> it is
> > > > > ignored. If it was decided to support limited RGB, then please
> update
> > > the
> > > > > docs of AVCOL_RANGE_JPEG/MPEG. Otherwise the color_range of an
> RGB
> > > format
> > > > > should not matter.
> > > > >
> > > > > On the other hand, if we decide to support limited RGB, then maybe
> a
> > > new
> > > > > member in color_range is better, this way we are able to specify
> more
> > > > > easily that we support limited YUV and full range RGB. (like ffplay
> > > > > typically does).
> > > > >
> > > >
> > > > Limited range RGB does NOT exist in the computer world, and I don't
> give
> > > a
> > > > fuck if broadcasting uses it. I've fought hard to keep it from
> getting
> > > into
> > > > AV1.
> > > > So no, we will not be supporting limited range RGB.
> > >
> > > You're very wrong. GPUs and HDMI (basically trash fire consumer
> > > garbage) sometimes seem to require you to feed limited RGB.
> > > _______________________________________________
> > > ffmpeg-devel mailing list
> > > ffmpeg-devel at ffmpeg.org
> > > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> > >
> >
> > Maybe if you took a second to read what I wrote. HDMI sometimes requires
> > limited range rgb because its derived from broadcasting junk where they
> had
> > technical limitations they weren't smart enough to overcome. GPUs can
> > generate or convert RGB to limited range only for transmission, through
> the
> > use of gamma LUTs I believe.
>
> By that logic, aren't all mpeg style codecs (including vp9, av1, etc.)
> also "broadcasting junk"? I mean, even YUV could be full range if it
> weren't for broadcasting legacy.
>

Not exactly, limited range YUV is a solution to an issue - out of gamut
colors. Its not the way this should have been solved though, out of the few
other ways I can think of.


> Either way, limited range RGB does NOT exist in computers, as in, not
> > inside codecs, nor is there anything supporting such, and we will
> certainly
> > not start doing it.
>
> Denial of reality, I guess.
>

Reality in a virtual world? No thanks, its whatever you make it.