Support for HDR images and video on the web

[chrisn]

The Color on the Web CG has been discussing requirements and proposed solutions for HDR imagery support on the web.

The current focus is on making the HTML <canvas> element HDR capable.

In our meeting on 25 April 2023 we heard a progress update, which includes focusing on a minimal proposal.

This issue tracks a media-related issue/proposal/work item/discussion

[chrisn]

Media Capabilities. Allows websites to query browser support for decoding media formats, including HDR video.

The spec doesn't include rendering capabilities. There was a long discussion of what API support is needed, and where it should be exposed, before we settled on CSS media queries.

Capturing the current status here, from w3c/media-capabilities#135:

• Mediaqueries-5 has a video-dynamic-range feature, which is separate from the dynamic-range feature on Screen
• similarly Mediaqueries-5 has a video-color-gamut feature , which is separate from the color-gamut feature on Screen
• The p3 gamut query value is defined relative to Display P3 (which now has a formal definition) rather than the related DCI P3

Media WG still has an open question in w3c/csswg-drafts#6891 on how to expose the video plane pixel ratio.