Initial selection and level filtering based on preferred codecs and MediaCapabilities

[robwalch]

This PR will...

Make initial variant selection based on preferred codec rather than the first variant in the multivariant playlist

• hls.firstAutoLevel is used to evaluate first level based on available codecs, resolution, framerate, default or autoselect audio options, audio channels, video-range, and score, not exceeding 1080p*, 30fps*, SDR, or stereo when possible.
  * Resolution and frame-rate of first auto level may exceed 1080p/30fps when initial bandwidth estimate allows and capLevelToPlayerSize is not enabled.

MediaCapabilities support

• Run mediaCapabilities.decodingInfo checks for UHD, HFR, and HDR variants, as well as multi-channel-audio renditions
  • Auto adaptations will not occur on variants running tests until they have passed
  • Failed checks will result in the level being removed

MediaCapabilities checks will be added to another PR to prevent switching up to UHD and HFR variants on constrained devices.

API enhancements

• Adds hls.firstAutoLevel getter, used internally to get the starting level index.
• hls.levels are sorted on height, frame rate, preferred codec, and video-range to infer order by quality. Height-first sorting allows cap-level-lontroller to set a max quality index at the maximum allowed resolution.
• Adds getters for all audio tracks and all subtitle tracks: hls.allAudioTracks and hls.allSubtitleTracks.
• In Base initial bandwidth estimate on first level bitrate #5649 abrEwmaDefaultEstimateMax was added. HLS.js will no longer start on the first variant (hls.firstLevel), or any variant of a preferred codec, if its BANDWIDTH exceeds this value.

Changes to Level parsing

• Level.bitrate uses variant BANDWIDTH (required peak bitrate) before falling back to optional AVERAGE-BANDWIDTH.
• Level.averageBitrate returns parsed AVERAGE-BANDWIDTH. Falls back to runtime average Level.realBitrate (which is only set when config.abrMaxWithRealBitrate is enabled) and finally Level.bitrate (BANDWIDTH).
• Added Level.frameRate returns parsed FRAME-RATE number or 0.
• Added Level.codecs returns parsed CODECS or emptry string.
• Added Level.score returns parsed SCORE number or 0.

Performance Improvements

• Reduced the number of times nextAutoLevel is evaluated.

Error handling improvements

• Switch back to auto mode when erroring in manual mode.
• Find alternate on BUFFER_APPEND_ERROR and BUFFER_ADD_CODEC_ERROR errors.
• Do not switch to playlists that have errored or failed to append media.
• Only reset level|track.fragmentError count on successful append.
• Reset append error count on successful appends for mixed muxed/unmuxed error handling

Why is this Pull Request needed?

HLS.js is expected to select more efficient codecs from the start of playback.

Are there any points in the code the reviewer needs to double check?

Switching from SDR to HDR, stereo to multi-channel audio, or from one codec family to another, requires a manual level change. Options to auto-select or prefer these configurations may be added in the future. Auto codec switching may be added after implementing MediaCapabilities MediaCapabilitiesDecodingInfo.transition if it proves to be well supported and implemented.

Additional MediaCapabilities options, like blocking and filtering levels before start (MANIFEST_PARSED), or choosing which variants to run checks on and what to do with supported results that are not smooth or power efficient will be considered upon request. Currently, all checks are performed after startup, and do not prevent manual selection of variants (levels) and renditions (audio tracks).

Resolves issues:

• Resolves Some video streams can't be played on microsoft edge chromium browser on windows 11 #4958 (unsupported container-less EC-3 fails over to AC-3)
• Resolves 7.1/8-channel AAC audio doesn't work #5162 (by selecting FLAC)
• Resolves capLevelToPlayerSize won't support multiple levels with identical resolutions  #5661
• Resolves capLevelToPlayerSize does not cap first level when startLevel is -1 #5664

Related issues (may not resolve but should improve)

• Related to Playback fails when audio group has two renditions (aac, ac-3) #5378

Checklist

• changes have been done against master branch, and PR does not conflict
• new unit / functional tests have been added (whenever applicable)
• API or design changes are documented in API.md

[littlespex]

I may not be following this correctly, but is the !isVideoRange(videoReange) portion of this filter correct? The comment says "remove invalid video-range levels", but this logic seems to do the opposite.

[robwalch]

Thanks for catching that. It's not doing anything because of the OR. Just pushed a test and fix: 823472d bde0ad2

Note: VIDEO-RANGE is optional, with an assumed value of 'SDR' when not specified. The point here is to remove variants with invalid or unknown values.