fix(mp4-tools): Fix two AV1 parsing issues

[nyanmisaka]

This PR will...

Fix two AV1 parsing issues that make Firefox fails to play HLS stream

Why is this Pull Request needed?

• fix(mp4-tools): Fix AV1 profile parsing

  Profile: unsigned right shift 5-bits for the 2nd av1CBox
  Level: bitwise AND the 2nd av1CBox with 0b11111(0x1f)

  Without this, Main av01.0.15M.08 is parsed as High av01.1.15M.08.
  In this case the High profile is not supprted in Firefox.

• fix(mp4-tools): set default color descriptions to satisfy Firefox

  In Firefox either you omit the chroma values, or you have to complete the rest of the color descriptions.

  Otherwise even the most basic AV1 Main 4:2:0 8-bit video will be reported as unsupported in HTMLMediaElement.canPlayType and MediaSource.isTypeSupported. Chromium is not affected by this.

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

See also

• https://aomediacodec.github.io/av1-isobmff/#av1codecconfigurationbox-syntax
• https://developer.mozilla.org/en-US/docs/Web/Media/Formats/Video_codecs#choosing_a_video_codec
• https://aomediacodec.github.io/av1-spec/#color-config-semantics

Resolves issues:

• av1 Main is mistakenly parsed as High profile and eventually fails in Firefox
  playlist:
  
  log:
  

• Firefox is unhapply with the chroma values
  

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

[robwalch]

Thank you for the contribution @nyanmisaka! I'll review soon with the hopes of including these fixes in the next release.

[robwalch]

I am concerned that some user-agents may still depend these fields being present.

https://aomediacodec.github.io/av1-isobmff/#av1codecconfigurationbox-syntax

The parameters sample entry 4CC, profile, level, tier, and bitDepth are all mandatory fields. If any of these fields are empty, or not within their allowed range, the processing device SHOULD treat it as an error. All the other fields (including their leading '.') are optional, mutually inclusive (all or none) fields. If not specified then the values listed in the table below are assumed.

mono_chrome	0
chromaSubsampling	110 (4:2:0)
colorPrimaries	01 (ITU-R BT.709)
transferCharacteristics	01 (ITU-R BT.709)
matrixCoefficients	01 (ITU-R BT.709)
videoFullRangeFlag	0 (studio swing representation)

Would adding the default values defined above work for Firefox?

[nyanmisaka]

It does work. I also changed the PR to add these as default values.

[robwalch]

Thanks @nyanmisaka,

Eventually (not in this PR), we may need a workaround for incomplete AV1 codec strings in Multivariant Playlist CODECS sort of like the workaround for opus/flac strings:

hls.js/src/utils/codecs.ts

Lines 132 to 172 in 6227816

	function getCodecCompatibleNameLower(
	lowerCaseCodec: LowerCaseCodecType,
	preferManagedMediaSource = true,
	): string {
	if (CODEC_COMPATIBLE_NAMES[lowerCaseCodec]) {
	return CODEC_COMPATIBLE_NAMES[lowerCaseCodec]!;
	}
	// Idealy fLaC and Opus would be first (spec-compliant) but
	// some browsers will report that fLaC is supported then fail.
	// see: https://bugs.chromium.org/p/chromium/issues/detail?id=1422728
	const codecsToCheck = {
	flac: ['flac', 'fLaC', 'FLAC'],
	opus: ['opus', 'Opus'],
	}[lowerCaseCodec];
	for (let i = 0; i < codecsToCheck.length; i++) {
	if (
	isCodecMediaSourceSupported(
	codecsToCheck[i],
	'audio',
	preferManagedMediaSource,
	)
	) {
	CODEC_COMPATIBLE_NAMES[lowerCaseCodec] = codecsToCheck[i];
	return codecsToCheck[i];
	}
	}
	return lowerCaseCodec;
	}
	const AUDIO_CODEC_REGEXP = /flac|opus/i;
	export function getCodecCompatibleName(
	codec: string,
	preferManagedMediaSource = true,
	): string {
	return codec.replace(AUDIO_CODEC_REGEXP, (m) =>
	getCodecCompatibleNameLower(
	m.toLowerCase() as LowerCaseCodecType,
	preferManagedMediaSource,

[nyanmisaka]

Indeed. Currently AV1 is not popular yet in HLS.
But as Apple provides native support for AV1, this problem will become apparent.

[robwalch]

Thanks @nyanmisaka,

Eventually (not in this PR), we may need a workaround for incomplete AV1 codec strings in Multivariant Playlist CODECS sort of like the workaround for opus/flac strings:

hls.js/src/utils/codecs.ts

Lines 132 to 172 in 6227816

	function getCodecCompatibleNameLower(
	lowerCaseCodec: LowerCaseCodecType,
	preferManagedMediaSource = true,
	): string {
	if (CODEC_COMPATIBLE_NAMES[lowerCaseCodec]) {
	return CODEC_COMPATIBLE_NAMES[lowerCaseCodec]!;
	}
	// Idealy fLaC and Opus would be first (spec-compliant) but
	// some browsers will report that fLaC is supported then fail.
	// see: https://bugs.chromium.org/p/chromium/issues/detail?id=1422728
	const codecsToCheck = {
	flac: ['flac', 'fLaC', 'FLAC'],
	opus: ['opus', 'Opus'],
	}[lowerCaseCodec];
	for (let i = 0; i < codecsToCheck.length; i++) {
	if (
	isCodecMediaSourceSupported(
	codecsToCheck[i],
	'audio',
	preferManagedMediaSource,
	)
	) {
	CODEC_COMPATIBLE_NAMES[lowerCaseCodec] = codecsToCheck[i];
	return codecsToCheck[i];
	}
	}
	return lowerCaseCodec;
	}
	const AUDIO_CODEC_REGEXP = /flac|opus/i;
	export function getCodecCompatibleName(
	codec: string,
	preferManagedMediaSource = true,
	): string {
	return codec.replace(AUDIO_CODEC_REGEXP, (m) =>
	getCodecCompatibleNameLower(
	m.toLowerCase() as LowerCaseCodecType,
	preferManagedMediaSource,