VIDEO-RANGE attribute support (HDR/SDR selection)

[robwalch]

Add support for STREAM-INF attribute VIDEO-RANGE.

These attributes describe display requirements that the player should check for before enabling and/or choosing a level.

If ignored, the codecs attributes may be enough to avoid selection of a level on some playback devices, but the display capabilities will be ignored.

• Authoring 4K and HDR HLS Streams

Additional context
For a brief overview see:

• HDR requirements for manifest parsed and level switching:
  • If a variant includes VIDEO-RANGE attribute value of "PQ" or "HLG", query MediaCapabilities decodingInfo for a video configuration with a transferFunction of "pq" or "hlg"
  • hdrMetadataType and colorGamut must be inferred from the codec and transfer function (Note: Not including in initial implementation - waiting for better user-agent support, or a use-case where including these produces expected results)
  • SDR renditions using avc/1080p/30fps/???bps or aac/stereo/???bps need not query MediaCapabilities (MediaSource.isTypeSupported is enough)
• Sample streams
  • https://developer.apple.com/streaming/examples/advanced-stream-dv-atmos.html
  • https://developer.apple.com/streaming/examples/advanced-stream-hevc.html
• References
  • https://developer.apple.com/documentation/http_live_streaming/hls_authoring_specification_for_apple_devices
  • https://tools.ietf.org/html/draft-pantos-hls-rfc8216bis-05

[OrenMe]

This is related to #2527 and in general should be handled in a generic way or as a plugin system that allows parsing arbitrary data from any tag

[robwalch]

@OrenMe

should be handled in a generic way

They are as far as parsing goes. At least in v1, level and track object attr should include these properties.

VIDEO-RANGE is more related to #2451 and adding support for or filtering of HDR renditions. Level selection should consider this attribute if present, and take advantage of MediaCapabilities (maps to TransferFunction) before selecting a 4k or HDR stream, or completing the filtering of renditions (levels and audio tracks) on MANIFEST_PARSED.

As far as HDCP-LEVEL goes I haven't seen any asks that would require us to use it internally. We just need to verify that it's available in level.attr that was covered in #5150.

[robwalch]

Moved HDCP from this issue to these under the DRM label:

• HDCP-LEVEL capping and EME error handling #4923
• HDCP-LEVEL filtering with HDCP Policy Check #5149

[robwalch]

MediaCapability checks for HDR VIDEO-RANGE/transferFunction support were added with #5704. Level.videoRange is also used in level sorting and selection, to maintain consistent playback stability and color quality.

What remains is whether HLS.js should add and use (as m)any of the following to infer a preference/support for initial selection of HDR variants:

• Test for HDR display support: matchMedia('(dynamic-range: high)') or matchMedia('(color-gamut: p3)')
  • Result can change depending on the display the browser window occupies.
  • The MediaQueryList by matchMedia should dispatch "change" events when capabilities change
• Config option: preferHDR boolean could be used to override query results

[dima-ravnur]

Hello everyone! Could somebody tell why HLG mapped to "PQ"? Shouldn't it be mapped to "HLG"?

[robwalch]

Hello everyone! Could somebody tell why HLG mapped to "PQ"? Shouldn't it be mapped to "HLG"?

Can you provide an example? I'm not sure what gave you that idea.

Can you file a new issue with examples, or comment on code changes?