From: Harry Wentland <harry.wentland@amd.com>
To: Pekka Paalanen <ppaalanen@gmail.com>
Cc: amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
sebastian@sebastianwick.net, mcasas@google.com,
jshargo@google.com, Shashank.Sharma@amd.com,
Deepak.Sharma@amd.com, Shirish.S@amd.com, Vitaly.Prosyak@amd.com,
aric.cyr@amd.com, Bhawanpreet.Lakha@amd.com,
Krunoslav.Kovac@amd.com, hersenxs.wu@amd.com,
Nicholas.Kazlauskas@amd.com, laurentiu.palcu@oss.nxp.com,
ville.syrjala@linux.intel.com, jeremy@jcline.org,
Brian Starkey <brian.starkey@arm.com>
Subject: Re: [RFC PATCH v3 1/6] drm/doc: Color Management and HDR10 RFC
Date: Wed, 22 Sep 2021 11:06:53 -0400 [thread overview]
Message-ID: <a13d64b1-7b24-5fd5-41d3-b55d2bd388e0@amd.com> (raw)
In-Reply-To: <4ed51ca0-ca98-cf84-33ed-ab172e3548d3@amd.com>
On 2021-09-20 20:14, Harry Wentland wrote:
> On 2021-09-15 10:01, Pekka Paalanen wrote:> On Fri, 30 Jul 2021 16:41:29 -0400
>> Harry Wentland <harry.wentland@amd.com> wrote:
>>
<snip>
>>> +If a display's maximum HDR white level is correctly reported it is trivial
>>> +to convert between all of the above representations of SDR white level. If
>>> +it is not, defining SDR luminance as a nits value, or a ratio vs a fixed
>>> +nits value is preferred, assuming we are blending in linear space.
>>> +
>>> +It is our experience that many HDR displays do not report maximum white
>>> +level correctly
>>
>> Which value do you refer to as "maximum white", and how did you measure
>> it?
>>
> Good question. I haven't played with those displays myself but I'll try to
> find out a bit more background behind this statement.
>
Some TVs report the EOTF but not the luminance values.
For an example edid-code capture of my eDP HDR panel:
HDR Static Metadata Data Block:
Electro optical transfer functions:
Traditional gamma - SDR luminance range
SMPTE ST2084
Supported static metadata descriptors:
Static metadata type 1
Desired content max luminance: 115 (603.666 cd/m^2)
Desired content max frame-average luminance: 109 (530.095 cd/m^2)
Desired content min luminance: 7 (0.005 cd/m^2)
I suspect on those TVs it looks like this:
HDR Static Metadata Data Block:
Electro optical transfer functions:
Traditional gamma - SDR luminance range
SMPTE ST2084
Supported static metadata descriptors:
Static metadata type 1
Windows has some defaults in this case and our Windows driver also has
some defaults.
Using defaults in the 1000-2000 nits range would yield much better
tone-mapping results than assuming the monitor can support a full
10k nits.
As an aside, recently we've come across displays where the max
average luminance is higher than the max peak luminance. This is
not a mistake but due to how the display's dimming zones work.
Not sure what impact this might have on tone-mapping, other than
to keep in mind that we can assume that max_avg < max_peak.
Harry
next prev parent reply other threads:[~2021-09-22 15:07 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-30 20:41 [RFC PATCH v3 0/6] A drm_plane API to support HDR planes Harry Wentland
2021-07-30 20:41 ` [RFC PATCH v3 1/6] drm/doc: Color Management and HDR10 RFC Harry Wentland
2021-08-02 16:30 ` Brian Starkey
2021-08-13 5:12 ` Sharma, Shashank
2021-08-16 11:10 ` Brian Starkey
2021-08-16 12:40 ` Harry Wentland
2021-08-16 13:37 ` sebastian
2021-09-06 21:20 ` Shankar, Uma
2021-09-15 14:36 ` Pekka Paalanen
2021-09-21 1:55 ` Harry Wentland
2021-09-15 14:01 ` Pekka Paalanen
2021-09-15 15:50 ` Jeremy Cline
2021-09-21 0:14 ` Harry Wentland
2021-09-21 13:31 ` Pekka Paalanen
2021-09-21 18:05 ` Harry Wentland
2021-09-22 8:31 ` Pekka Paalanen
2021-09-22 15:28 ` Harry Wentland
2021-09-23 7:43 ` Pekka Paalanen
2021-09-30 13:04 ` Repository for additional color and HDR related documentation (Re: [RFC PATCH v3 1/6] drm/doc: Color Management and HDR10 RFC) Pekka Paalanen
2021-09-22 15:06 ` Harry Wentland [this message]
2021-09-23 8:01 ` [RFC PATCH v3 1/6] drm/doc: Color Management and HDR10 RFC Pekka Paalanen
2021-09-23 13:40 ` Harry Wentland
2021-09-23 15:50 ` Vitaly Prosyak
2021-07-30 20:41 ` [RFC PATCH v3 2/6] drm/color: Add transfer functions for HDR/SDR on drm_plane Harry Wentland
2021-07-30 20:41 ` [RFC PATCH v3 3/6] drm/color: Add output transfer function to crtc Harry Wentland
2021-07-30 20:41 ` [RFC PATCH v3 4/6] drm/color: Add sdr boost property Harry Wentland
2021-07-30 20:41 ` [RFC PATCH v3 5/6] drm/color: Add color space plane property Harry Wentland
2021-07-30 20:41 ` [RFC PATCH v3 6/6] drm/amd/display: reformat YCbCr-RGB conversion matrix Harry Wentland
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