Intent to Prototype: MediaCapabilities: Query HDR with decodingInfo()

[nguye...@gmail.com]

Contact emails

gw...@microsoft.com,gur...@microsoft.com,vi...@microsoft.com

Explainer

https://github.com/w3c/media-capabilities/blob/master/explainer.md#hdr

Design doc/Spec

https://w3c.github.io/media-capabilities/#videoconfiguration

Initial Media Capabilities TAG review. The addition of spatialAudio is small, and does not require further review.

Summary

This specification provides APIs for websites to detect whether HDR formats, i.e. Dolby Vision, HDR10(+), and HLG, can be decoded and rendered by the browser.

For HDR support detection, there are three main components whose capabilities need to be surfaced -- the decoder, renderer, and screen. The decoder takes in an encoded stream and produces a decoded stream understood by the renderer, which in turn maps the stream's signals to those the screen can properly output. Most of the time, the decoder and renderer are part of the UA while the screen represents the physical output monitor, whether this be a computer monitor or TV. To match this natural modularity between the UA and the screen, this API is compartmentalized into two parts:

MediaCapabilities.decodingInfo(): handles the UA pieces, namely decoding and rendering.

CSS Media Queries: handles the screen capabilities.

Motivation

This API allows capable clients to enjoy high-end media playback experiences. Otherwise, HDR content does not get served to preserve networking bandwidth, playback quality, and power consumption.

Risks

Interoperability and Compatibility

The main risk is that it fails to become an interoperable part of the web platform if other browsers do not implement it.

Edge: Public support

Firefox: No signals

Safari: Public support

Web / Framework developers: Public support

Ergonomics

N/A

Activation

N/A

Debuggability

The primary debugging need will probably arise when there is a mismatch between what the API claims and what the UA can do. To help devs report the issue, logging for HDR can be added to the ‘video’ tab on about://media-internals.

Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, Chrome OS, Android, and Android WebView)?

Yes.

Is this feature fully tested by web-platform-tests?

N/A (Not request approval to ship).

Link to entry on the feature dashboard

https://www.chromestatus.com/feature/6640863931269120

Requesting approval to ship?

No.