[FFmpeg-devel] [PATCH v2 5/6] avutil/csp: add EOTF function definitions

[Michael Niedermayer]

Hi

On Sat, Nov 30, 2024 at 03:27:53PM +0100, Niklas Haas wrote:
> On Sat, 30 Nov 2024 15:23:50 +0100 Niklas Haas <ffmpeg at haasn.xyz> wrote:
> > From: Niklas Haas <git at haasn.dev>
> >
> > The existing av_csp_trc_func_from_id() mostly implements the OETF, except for
> > PQ. As such, we are currently missing a precise definition of an ITU-R EOTF.
> > Introduce the new functions av_csp_itu_eotf() and av_csp_itu_eotf_inv(), to fill
> > this void. Note that this is not possible in all cases, e.g. AVCOL_TRC_LOG which
> > has no corresponding EOTF definition in any ITU-R standard.
> >
> > Note that we cannot implement the proper HLG and SMPTE 428 OOTFs without access
> > to all three color channels, because they are not independent per channel. As a
> > result, we need to define a new type to encapsulate a color triplet. I have
> > tentatively named this AVColor, in the hopes that it will become useful in other
> > contexts as well. The choice of an array rather than explicitly named fields is
> > to greatly simplify per-channel processing, matrix multiplications, and the
> > like.
> 
> Forgot to update the commit message. I decided to nuke AVColor in favor of
> passing a double[3] directly. It only makes the code inside the test framework
> marginally less pretty, and actually improves the usability of the API in other
> contexts IMO.
> 
> > ---
> >  doc/APIchanges      |   4 +
> >  libavutil/csp.c     | 205 ++++++++++++++++++++++++++++++++++++++++++++
> >  libavutil/csp.h     |  33 +++++++
> >  libavutil/version.h |   2 +-
> >  4 files changed, 243 insertions(+), 1 deletion(-)
> >
> > diff --git a/doc/APIchanges b/doc/APIchanges
> > index db72121a61..12a2165837 100644
> > --- a/doc/APIchanges
> > +++ b/doc/APIchanges
> > @@ -2,6 +2,10 @@ The last version increases of all libraries were on 2024-03-07
> >
> >  API changes, most recent first:
> >
> > +2024-11-25 - xxxxxxxxxx - lavu 59.49.100 - csp.h
> > +  Add struct AVColor, type av_csp_eotf_function, av_csp_itu_eotf() and

This still talks about AVColor

thx

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Some people wanted to paint the bikeshed green, some blue and some pink.
People argued and fought, when they finally agreed, only rust was left.
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