- From: Pierre-Anthony Lemieux via GitHub <sysbot+gh@w3.org>
- Date: Thu, 26 Jan 2017 20:24:18 +0000
- To: public-css-archive@w3.org
> the problem with that is that HDR luminance is an absolute scale, > while SDR is a relative one (relative to a white diffuser). sRGB defines a reference display with a luminance level of 80 cd/m^2 (see Section 4.1 at IEC 61966-2-1), so I would not characterize sRGB as relative to a white diffuser. Both sRGB and Rec 2100/PQ (HDR) content are effectively mastered against an absolute scale. They are also both experienced, by the end-users, on a wide range of displays with different luminance characteristics. > If we map SDR to HDR, @frivoal It would be good to list the use cases where this might happen in order to best answer the question of what peak luminance level should be used when compositing SDR and HDR content a common plane. Did you have specific ones in mind? In the case of subtitles/captions, it is necessary to allow the author to specify that peak luminance level to ensure the right experience. In the long-run, subtitle/captions should ideally be specified using HDR pixels natively (instead of being specified in sRGB and composited using a gain value). -- GitHub Notification of comment by palemieux Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/554#issuecomment-275502971 using your GitHub account
Received on Thursday, 26 January 2017 20:24:24 UTC