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feat(MediaCap): Guess the codecs of multiplexd stream for MediaCap
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If we have a multiplexd stream with audio and video, the video
codecs are a combined string containing both audio and video codecs.
Before sending the request to decodingInfo(), we should check which
codec is audio and which one is video.

This is a follow-up of commit 966a756.

Issue shaka-project#1391

Change-Id: Ic9b1c5972a99f63a715c74ae068b85f43efac447
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@michellezhuogg
michellezhuogg committed Mar 30, 2021
1 parent 863e345 commit 198a6d4
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Showing 3 changed files with 134 additions and 125 deletions.
130 changes: 11 additions & 119 deletions lib/hls/hls_parser.js
View file
Expand Up @@ -596,17 +596,20 @@ shaka.hls.HlsParser = class {
const allCodecs = this.getCodecsForVariantTag_(variantTag);

if (subGroupId) {
const textCodecs = this.guessCodecsSafe_(ContentType.TEXT, allCodecs);
const textCodecs = shaka.util.ManifestParserUtils.guessCodecsSafe(
ContentType.TEXT, allCodecs);
goog.asserts.assert(textCodecs != null, 'Text codecs should be valid.');
this.groupIdToCodecsMap_.set(subGroupId, textCodecs);
shaka.util.ArrayUtils.remove(allCodecs, textCodecs);
}
if (audioGroupId) {
const codecs = this.guessCodecs_(ContentType.AUDIO, allCodecs);
const codecs = shaka.util.ManifestParserUtils.guessCodecs(
ContentType.AUDIO, allCodecs);
this.groupIdToCodecsMap_.set(audioGroupId, codecs);
}
if (videoGroupId) {
const codecs = this.guessCodecs_(ContentType.VIDEO, allCodecs);
const codecs = shaka.util.ManifestParserUtils.guessCodecs(
ContentType.VIDEO, allCodecs);
this.groupIdToCodecsMap_.set(videoGroupId, codecs);
}
}
Expand Down Expand Up @@ -774,8 +777,10 @@ shaka.hls.HlsParser = class {
return audio && audio.verbatimMediaPlaylistUri == streamURI;
});

const videoCodecs = this.guessCodecsSafe_(ContentType.VIDEO, allCodecs);
const audioCodecs = this.guessCodecsSafe_(ContentType.AUDIO, allCodecs);
const videoCodecs = shaka.util.ManifestParserUtils.guessCodecsSafe(
ContentType.VIDEO, allCodecs);
const audioCodecs = shaka.util.ManifestParserUtils.guessCodecsSafe(
ContentType.AUDIO, allCodecs);

if (audioCodecs && !videoCodecs) {
// There are no associated media tags, and there's only audio codec,
Expand Down Expand Up @@ -1196,7 +1201,7 @@ shaka.hls.HlsParser = class {
}

const closedCaptions = this.getClosedCaptions_(tag, type);
const codecs = this.guessCodecs_(type, allCodecs);
const codecs = shaka.util.ManifestParserUtils.guessCodecs(type, allCodecs);
const streamInfo = await this.createStreamInfo_(verbatimMediaPlaylistUri,
codecs, type, /* language= */ 'und', /* primary= */ false,
/* name= */ null, /* channelcount= */ null, closedCaptions,
Expand Down Expand Up @@ -2291,65 +2296,6 @@ shaka.hls.HlsParser = class {
}
}

/**
* Attempts to guess which codecs from the codecs list belong to a given
* content type.
* Assumes that at least one codec is correct, and throws if none are.
*
* @param {string} contentType
* @param {!Array.<string>} codecs
* @return {string}
* @private
*/
guessCodecs_(contentType, codecs) {
if (codecs.length == 1) {
return codecs[0];
}

const match = this.guessCodecsSafe_(contentType, codecs);
// A failure is specifically denoted by null; an empty string represents a
// valid match of no codec.
if (match != null) {
return match;
}

// Unable to guess codecs.
throw new shaka.util.Error(
shaka.util.Error.Severity.CRITICAL,
shaka.util.Error.Category.MANIFEST,
shaka.util.Error.Code.HLS_COULD_NOT_GUESS_CODECS,
codecs);
}

/**
* Attempts to guess which codecs from the codecs list belong to a given
* content type. Does not assume a single codec is anything special, and does
* not throw if it fails to match.
*
* @param {string} contentType
* @param {!Array.<string>} codecs
* @return {?string} or null if no match is found
* @private
*/
guessCodecsSafe_(contentType, codecs) {
const formats =
shaka.hls.HlsParser.CODEC_REGEXPS_BY_CONTENT_TYPE_[contentType];
for (const format of formats) {
for (const codec of codecs) {
if (format.test(codec.trim())) {
return codec.trim();
}
}
}

// Text does not require a codec string.
if (contentType == shaka.util.ManifestParserUtils.ContentType.TEXT) {
return '';
}

return null;
}

/**
* Replaces the variables of a given URI.
*
Expand Down Expand Up @@ -2719,60 +2665,6 @@ shaka.hls.HlsParser.StreamInfo;
shaka.hls.HlsParser.StreamInfos;


/**
* A list of regexps to detect well-known video codecs.
*
* @const {!Array.<!RegExp>}
* @private
*/
shaka.hls.HlsParser.VIDEO_CODEC_REGEXPS_ = [
/^avc/,
/^hev/,
/^hvc/,
/^vp0?[89]/,
/^av1$/,
];


/**
* A list of regexps to detect well-known audio codecs.
*
* @const {!Array.<!RegExp>}
* @private
*/
shaka.hls.HlsParser.AUDIO_CODEC_REGEXPS_ = [
/^vorbis$/,
/^opus$/,
/^flac$/,
/^mp4a/,
/^[ae]c-3$/,
];


/**
* A list of regexps to detect well-known text codecs.
*
* @const {!Array.<!RegExp>}
* @private
*/
shaka.hls.HlsParser.TEXT_CODEC_REGEXPS_ = [
/^vtt$/,
/^wvtt/,
/^stpp/,
];


/**
* @const {!Object.<string, !Array.<!RegExp>>}
* @private
*/
shaka.hls.HlsParser.CODEC_REGEXPS_BY_CONTENT_TYPE_ = {
'audio': shaka.hls.HlsParser.AUDIO_CODEC_REGEXPS_,
'video': shaka.hls.HlsParser.VIDEO_CODEC_REGEXPS_,
'text': shaka.hls.HlsParser.TEXT_CODEC_REGEXPS_,
};


/**
* @const {!Object.<string, string>}
* @private
Expand Down
114 changes: 114 additions & 0 deletions lib/util/manifest_parser_utils.js
View file
Expand Up @@ -7,6 +7,7 @@
goog.provide('shaka.util.ManifestParserUtils');

goog.require('goog.Uri');
goog.require('shaka.util.Error');
goog.require('shaka.util.Functional');


Expand Down Expand Up @@ -58,6 +59,66 @@ shaka.util.ManifestParserUtils = class {
keyIds: new Set(),
};
}


/**
* Attempts to guess which codecs from the codecs list belong to a given
* content type.
* Assumes that at least one codec is correct, and throws if none are.
*
* @param {string} contentType
* @param {!Array.<string>} codecs
* @return {string}
*/
static guessCodecs(contentType, codecs) {
if (codecs.length == 1) {
return codecs[0];
}

const match = shaka.util.ManifestParserUtils.guessCodecsSafe(
contentType, codecs);
// A failure is specifically denoted by null; an empty string represents a
// valid match of no codec.
if (match != null) {
return match;
}

// Unable to guess codecs.
throw new shaka.util.Error(
shaka.util.Error.Severity.CRITICAL,
shaka.util.Error.Category.MANIFEST,
shaka.util.Error.Code.HLS_COULD_NOT_GUESS_CODECS,
codecs);
}


/**
* Attempts to guess which codecs from the codecs list belong to a given
* content type. Does not assume a single codec is anything special, and does
* not throw if it fails to match.
*
* @param {string} contentType
* @param {!Array.<string>} codecs
* @return {?string} or null if no match is found
*/
static guessCodecsSafe(contentType, codecs) {
const formats = shaka.util.ManifestParserUtils
.CODEC_REGEXPS_BY_CONTENT_TYPE_[contentType];
for (const format of formats) {
for (const codec of codecs) {
if (format.test(codec.trim())) {
return codec.trim();
}
}
}

// Text does not require a codec string.
if (contentType == shaka.util.ManifestParserUtils.ContentType.TEXT) {
return '';
}

return null;
}
};


Expand Down Expand Up @@ -91,3 +152,56 @@ shaka.util.ManifestParserUtils.TextStreamKind = {
* @const {number}
*/
shaka.util.ManifestParserUtils.GAP_OVERLAP_TOLERANCE_SECONDS = 1 / 15;


/**
* A list of regexps to detect well-known video codecs.
*
* @const {!Array.<!RegExp>}
* @private
*/
shaka.util.ManifestParserUtils.VIDEO_CODEC_REGEXPS_ = [
/^avc/,
/^hev/,
/^hvc/,
/^vp0?[89]/,
/^av1$/,
];


/**
* A list of regexps to detect well-known audio codecs.
*
* @const {!Array.<!RegExp>}
* @private
*/
shaka.util.ManifestParserUtils.AUDIO_CODEC_REGEXPS_ = [
/^vorbis$/,
/^opus$/,
/^flac$/,
/^mp4a/,
/^[ae]c-3$/,
];


/**
* A list of regexps to detect well-known text codecs.
*
* @const {!Array.<!RegExp>}
* @private
*/
shaka.util.ManifestParserUtils.TEXT_CODEC_REGEXPS_ = [
/^vtt$/,
/^wvtt/,
/^stpp/,
];


/**
* @const {!Object.<string, !Array.<!RegExp>>}
*/
shaka.util.ManifestParserUtils.CODEC_REGEXPS_BY_CONTENT_TYPE_ = {
'audio': shaka.util.ManifestParserUtils.AUDIO_CODEC_REGEXPS_,
'video': shaka.util.ManifestParserUtils.VIDEO_CODEC_REGEXPS_,
'text': shaka.util.ManifestParserUtils.TEXT_CODEC_REGEXPS_,
};
15 changes: 9 additions & 6 deletions lib/util/stream_utils.js
View file
Expand Up @@ -433,15 +433,18 @@ shaka.util.StreamUtils = class {
};

if (video) {
let audioCodec;
let videoCodec = video.codecs;

let videoCodecs = video.codecs;
// For multiplexed streams with audio+video codecs, the config should have
// AudioConfiguration and VideoConfiguration.
if (video.codecs.includes(',')) {
[videoCodec, audioCodec] = video.codecs.split(',');
const allCodecs = video.codecs.split(',');
videoCodecs = shaka.util.ManifestParserUtils.guessCodecs(
ContentType.VIDEO, allCodecs);
const audioCodecs = shaka.util.ManifestParserUtils.guessCodecs(
ContentType.AUDIO, allCodecs);

const audioFullType = shaka.util.MimeUtils.getFullOrConvertedType(
video.mimeType, audioCodec, ContentType.AUDIO);
video.mimeType, audioCodecs, ContentType.AUDIO);
mediaDecodingConfig.audio = {
contentType: audioFullType,
channels: 2,
Expand All @@ -451,7 +454,7 @@ shaka.util.StreamUtils = class {
};
}
const fullType = shaka.util.MimeUtils.getFullOrConvertedType(
video.mimeType, videoCodec, ContentType.VIDEO);
video.mimeType, videoCodecs, ContentType.VIDEO);
// VideoConfiguration
mediaDecodingConfig.video = {
contentType: fullType,
Expand Down

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