Agenda, TPAC 2019 ColorWeb CG Meeting.

I had hoped that the ICC white paper on HDR with ICC would be available 
for discussion by this community group. Alas, that document does not yet 
have consensus within ICC so has not yet been published. Once it is, I 
will send a link to this CG for discussion.

Topics which would be particularly useful to discuss:

* Working Colorspace in CSS Color 4

For Web compat, things like compositing, gradients, anti-aliasing, and 
general color interpolation defaults to sRGB. This is not a linear 
space, so the results of computations are wrong. A new CSS property, 
working-colorspace, would allow this to be altered. This is particularly 
needed if any element is in a wider gamut colorspace.

There have been various suggestions for suitable values. XYZ would 
clearly work and would not clip. linear sRGB with headroom and footroom 
to represent out of gamut colors would also work.

* HDR and the Web, compositing SDR with HDR

Typical use cases include showing some information (subtitles, actor bio 
as a Web page) composited on top of HDR video. HDR (at least in PQ 
encoding) uses absolute luminance, so where should sRGB white be placed? 
Clearly not at 80 nits, clearly not at 4000 nits or whatever the display 
is capable of for small hilights, and probably not at 1200 nts or 
whatever full-screen value the display is capable of. How should that 
work with HLG? What is the influence of scene metadata on this compositing?

* Image formats for HDR

Still images, such as stills from a movie or HDR photography, need to be 
displayed on the Web. Ideally, W3C would not develop a new format but 
use an existing, open, widely implementable one.

Chris Lilley
Technical Director @ W3C
W3C Strategy Team, Core Web Design
W3C Architecture & Technology Team, Core Web & Media

Received on Monday, 16 September 2019 08:57:13 UTC