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@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@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.h...
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