[RFC PATCH v3 1/6] drm/doc: Color Management and HDR10 RFC

[Jeremy Cline]

On Wed, 2021-09-15 at 17:01 +0300, Pekka Paalanen wrote:
> On Fri, 30 Jul 2021 16:41:29 -0400
> Harry Wentland <harry.wentland at amd.com> wrote:
> 
> > Use the new DRM RFC doc section to capture the RFC previously only
> > described in the cover letter at
> > https://patchwork.freedesktop.org/series/89506/
> > 
> > v3:
> >  * Add sections on single-plane and multi-plane HDR
> >  * Describe approach to define HW details vs approach to define SW
> > intentions
> >  * Link Jeremy Cline's excellent HDR summaries
> >  * Outline intention behind overly verbose doc
> >  * Describe FP16 use-case
> >  * Clean up links
> > 
> > v2: create this doc
> > 
> > v1: n/a
> > 
> > Signed-off-by: Harry Wentland <harry.wentland at amd.com>
> 
> Hi Harry,
> 
> I finally managed to go through this, comments below. Excellent to
> have
> pictures included. I wrote this reply over several days, sorry if
> it's
> not quite coherent.
> 
> 
> 
> 

<snip>

> > +
> > +
> > +Overview and background
> > +=======================
> > +
> > +I highly recommend you read `Jeremy Cline's HDR primer`_
> > +
> > +Jeremy Cline did a much better job describing this. I highly
> > recommend
> > +you read it at [1]:
> > +
> > +.. _Jeremy Cline's HDR primer:
> > https://www.jcline.org/blog/fedora/graphics/hdr/2021/05/07/hdr-in-linux-p1.html
> 
> That's a nice write-up I didn't know about, thanks.
> 
> I just wish such write-ups would be somehow peer-reviewed for
> correctness and curated for proper referencing. Perhaps like we
> develop
> code: at least some initial peer review and then fixes when anyone
> notices something to improve. Like... what you are doing here! :-)
> 
> The post is perhaps a bit too narrow with OETF/EOTF terms,
> accidentally
> implying that OETF = EOTF^-1 which is not generally true, but that
> all
> depends on which O-to-E or E-to-O functions one is talking about.
> Particularly there is a difference between functions used for signal
> compression which needs an exact matching inverse function, and
> functions containing tone-mapping and artistic effects that when
> concatenated result in the (non-identity) OOTF.
> 
> Nothing in the post seems to disagree with my current understanding
> FWI'mW.

I'm more than happy to update things that are incorrect or mis-leading
since the last thing I want to do is muddy the waters. Personally, I
would much prefer that any useful content from it be peer-reviewed and
included directly in the documentation since, well, it's being hosted
out of my laundry room and the cats have a habit of turning off the
UPS...

Do let me know if I can be of any assistance there; I'm no longer
employed to do anything HDR-related, but I do like clear documentation
so I could dedicate a bit of free time to it.

- Jeremy