/*! @license
* Shaka Player
* Copyright 2016 Google LLC
* SPDX-License-Identifier: Apache-2.0
*/
goog.provide('shaka.hls.HlsParser');
goog.require('goog.Uri');
goog.require('goog.asserts');
goog.require('shaka.hls.ManifestTextParser');
goog.require('shaka.hls.Playlist');
goog.require('shaka.hls.PlaylistType');
goog.require('shaka.hls.Tag');
goog.require('shaka.hls.Utils');
goog.require('shaka.log');
goog.require('shaka.media.DrmEngine');
goog.require('shaka.media.InitSegmentReference');
goog.require('shaka.media.ManifestParser');
goog.require('shaka.media.PresentationTimeline');
goog.require('shaka.media.SegmentIndex');
goog.require('shaka.media.SegmentReference');
goog.require('shaka.net.DataUriPlugin');
goog.require('shaka.net.NetworkingEngine');
goog.require('shaka.util.ArrayUtils');
goog.require('shaka.util.BufferUtils');
goog.require('shaka.util.DataViewReader');
goog.require('shaka.util.Error');
goog.require('shaka.util.FakeEvent');
goog.require('shaka.util.Functional');
goog.require('shaka.util.LanguageUtils');
goog.require('shaka.util.ManifestParserUtils');
goog.require('shaka.util.MimeUtils');
goog.require('shaka.util.Mp4Parser');
goog.require('shaka.util.Mp4BoxParsers');
goog.require('shaka.util.Networking');
goog.require('shaka.util.OperationManager');
goog.require('shaka.util.Pssh');
goog.require('shaka.util.Timer');
goog.requireType('shaka.hls.Segment');
/**
* HLS parser.
*
* @implements {shaka.extern.ManifestParser}
* @export
*/
shaka.hls.HlsParser = class {
/**
* Creates an Hls Parser object.
*/
constructor() {
/** @private {?shaka.extern.ManifestParser.PlayerInterface} */
this.playerInterface_ = null;
/** @private {?shaka.extern.ManifestConfiguration} */
this.config_ = null;
/** @private {number} */
this.globalId_ = 1;
/** @private {!Map.<string, string>} */
this.globalVariables_ = new Map();
/**
* A map from group id to stream infos created from the media tags.
* @private {!Map.<string, !Array.<?shaka.hls.HlsParser.StreamInfo>>}
*/
this.groupIdToStreamInfosMap_ = new Map();
/**
* The values are strings of the form "<VIDEO URI> - <AUDIO URI>",
* where the URIs are the verbatim media playlist URIs as they appeared in
* the master playlist.
*
* Used to avoid duplicates that vary only in their text stream.
*
* @private {!Set.<string>}
*/
this.variantUriSet_ = new Set();
/**
* A map from (verbatim) media playlist URI to stream infos representing the
* playlists.
*
* On update, used to iterate through and update from media playlists.
*
* On initial parse, used to iterate through and determine minimum
* timestamps, offsets, and to handle TS rollover.
*
* During parsing, used to avoid duplicates in the async methods
* createStreamInfoFromMediaTag_ and createStreamInfoFromVariantTag_.
*
* During parsing of updates, used by getStartTime_ to determine the start
* time of the first segment from existing segment references.
*
* @private {!Map.<string, shaka.hls.HlsParser.StreamInfo>}
*/
this.uriToStreamInfosMap_ = new Map();
/** @private {?shaka.media.PresentationTimeline} */
this.presentationTimeline_ = null;
/**
* The master playlist URI, after redirects.
*
* @private {string}
*/
this.masterPlaylistUri_ = '';
/** @private {shaka.hls.ManifestTextParser} */
this.manifestTextParser_ = new shaka.hls.ManifestTextParser();
/**
* This is the number of seconds we want to wait between finishing a
* manifest update and starting the next one. This will be set when we parse
* the manifest.
*
* @private {number}
*/
this.updatePlaylistDelay_ = 0;
/**
* This timer is used to trigger the start of a manifest update. A manifest
* update is async. Once the update is finished, the timer will be restarted
* to trigger the next update. The timer will only be started if the content
* is live content.
*
* @private {shaka.util.Timer}
*/
this.updatePlaylistTimer_ = new shaka.util.Timer(() => {
this.onUpdate_();
});
/** @private {shaka.hls.HlsParser.PresentationType_} */
this.presentationType_ = shaka.hls.HlsParser.PresentationType_.VOD;
/** @private {?shaka.extern.Manifest} */
this.manifest_ = null;
/** @private {number} */
this.maxTargetDuration_ = 0;
/** @private {number} */
this.minTargetDuration_ = Infinity;
/** Partial segments target duration.
* @private {number}
*/
this.partialTargetDuration_ = 0;
/** @private {number} */
this.lowLatencyPresentationDelay_ = 0;
/** @private {shaka.util.OperationManager} */
this.operationManager_ = new shaka.util.OperationManager();
/** @private {!Array.<!Array.<!shaka.media.SegmentReference>>} */
this.segmentsToNotifyByStream_ = [];
/** A map from closed captions' group id, to a map of closed captions info.
* {group id -> {closed captions channel id -> language}}
* @private {Map.<string, Map.<string, string>>}
*/
this.groupIdToClosedCaptionsMap_ = new Map();
/** True if some of the variants in the playlist is encrypted with AES-128.
* @private {boolean} */
this.aesEncrypted_ = false;
/** @private {Map.<string, string>} */
this.groupIdToCodecsMap_ = new Map();
/** @private {?number} */
this.playlistStartTime_ = null;
/** A cache mapping EXT-X-MAP tag info to the InitSegmentReference created
* from the tag.
* The key is a string combining the EXT-X-MAP tag's absolute uri, and
* its BYTERANGE if available.
* {!Map.<string, !shaka.media.InitSegmentReference>} */
this.mapTagToInitSegmentRefMap_ = new Map();
/**
* A cache mapping a discontinuity sequence number of a segment with
* EXT-X-DISCONTINUITY tag into its timestamp offset.
* Key: the discontinuity sequence number of a segment
* Value: the segment reference's timestamp offset.
* {!Map.<number, number>}
*/
this.discontinuityToTso_ = new Map();
/** @private {boolean} */
this.lowLatencyMode_ = false;
}
/**
* @override
* @exportInterface
*/
configure(config) {
this.config_ = config;
}
/**
* @override
* @exportInterface
*/
async start(uri, playerInterface) {
goog.asserts.assert(this.config_, 'Must call configure() before start()!');
this.playerInterface_ = playerInterface;
this.lowLatencyMode_ = playerInterface.isLowLatencyMode();
const response = await this.requestManifest_(uri);
// Record the master playlist URI after redirects.
this.masterPlaylistUri_ = response.uri;
goog.asserts.assert(response.data, 'Response data should be non-null!');
await this.parseManifest_(response.data);
// Start the update timer if we want updates.
const delay = this.updatePlaylistDelay_;
if (delay > 0) {
this.updatePlaylistTimer_.tickAfter(/* seconds= */ delay);
}
goog.asserts.assert(this.manifest_, 'Manifest should be non-null');
return this.manifest_;
}
/**
* @override
* @exportInterface
*/
stop() {
// Make sure we don't update the manifest again. Even if the timer is not
// running, this is safe to call.
if (this.updatePlaylistTimer_) {
this.updatePlaylistTimer_.stop();
this.updatePlaylistTimer_ = null;
}
/** @type {!Array.<!Promise>} */
const pending = [];
if (this.operationManager_) {
pending.push(this.operationManager_.destroy());
this.operationManager_ = null;
}
this.playerInterface_ = null;
this.config_ = null;
this.variantUriSet_.clear();
this.manifest_ = null;
this.uriToStreamInfosMap_.clear();
this.groupIdToStreamInfosMap_.clear();
this.groupIdToCodecsMap_.clear();
this.globalVariables_.clear();
return Promise.all(pending);
}
/**
* @override
* @exportInterface
*/
async update() {
if (!this.isLive_()) {
return;
}
/** @type {!Array.<!Promise>} */
const updates = [];
// Reset the start time for the new media playlist.
this.playlistStartTime_ = null;
const streamInfos = Array.from(this.uriToStreamInfosMap_.values());
// Wait for the first stream info created, so that the start time is fetched
// and can be reused.
if (streamInfos.length) {
await this.updateStream_(streamInfos[0]);
}
for (let i = 1; i < streamInfos.length; i++) {
updates.push(this.updateStream_(streamInfos[i]));
}
await Promise.all(updates);
}
/**
* Updates a stream.
*
* @param {!shaka.hls.HlsParser.StreamInfo} streamInfo
* @return {!Promise}
* @private
*/
async updateStream_(streamInfo) {
const PresentationType = shaka.hls.HlsParser.PresentationType_;
const manifestUri = streamInfo.absoluteMediaPlaylistUri;
const uriObj = new goog.Uri(manifestUri);
if (this.lowLatencyMode_ && streamInfo.canSkipSegments) {
// Enable delta updates. This will replace older segments with
// 'EXT-X-SKIP' tag in the media playlist.
uriObj.setQueryData(new goog.Uri.QueryData('_HLS_skip=YES'));
}
const response = await this.requestManifest_(uriObj.toString());
/** @type {shaka.hls.Playlist} */
const playlist = this.manifestTextParser_.parsePlaylist(
response.data, response.uri);
if (playlist.type != shaka.hls.PlaylistType.MEDIA) {
throw new shaka.util.Error(
shaka.util.Error.Severity.CRITICAL,
shaka.util.Error.Category.MANIFEST,
shaka.util.Error.Code.HLS_INVALID_PLAYLIST_HIERARCHY);
}
/** @type {!Array.<!shaka.hls.Tag>} */
const variablesTags = shaka.hls.Utils.filterTagsByName(playlist.tags,
'EXT-X-DEFINE');
const mediaVariables = this.parseMediaVariables_(variablesTags);
const stream = streamInfo.stream;
const segments = await this.createSegments_(
streamInfo.verbatimMediaPlaylistUri, playlist, stream.type,
stream.mimeType, streamInfo.mediaSequenceToStartTime, mediaVariables,
streamInfo.discontinuityToMediaSequence);
stream.segmentIndex.mergeAndEvict(
segments, this.presentationTimeline_.getSegmentAvailabilityStart());
if (segments.length) {
const mediaSequenceNumber = shaka.hls.Utils.getFirstTagWithNameAsNumber(
playlist.tags, 'EXT-X-MEDIA-SEQUENCE', 0);
const playlistStartTime = streamInfo.mediaSequenceToStartTime.get(
mediaSequenceNumber);
stream.segmentIndex.evict(playlistStartTime);
}
const newestSegment = segments[segments.length - 1];
goog.asserts.assert(newestSegment, 'Should have segments!');
// Once the last segment has been added to the playlist,
// #EXT-X-ENDLIST tag will be appended.
// If that happened, treat the rest of the EVENT presentation as VOD.
const endListTag =
shaka.hls.Utils.getFirstTagWithName(playlist.tags, 'EXT-X-ENDLIST');
if (endListTag) {
// Convert the presentation to VOD and set the duration to the last
// segment's end time.
this.setPresentationType_(PresentationType.VOD);
this.presentationTimeline_.setDuration(newestSegment.endTime);
}
}
/**
* @override
* @exportInterface
*/
onExpirationUpdated(sessionId, expiration) {
// No-op
}
/**
* Parses the manifest.
*
* @param {BufferSource} data
* @return {!Promise}
* @private
*/
async parseManifest_(data) {
const Utils = shaka.hls.Utils;
goog.asserts.assert(this.masterPlaylistUri_,
'Master playlist URI must be set before calling parseManifest_!');
const playlist = this.manifestTextParser_.parsePlaylist(
data, this.masterPlaylistUri_);
// We don't support directly providing a Media Playlist.
// See the error code for details.
if (playlist.type != shaka.hls.PlaylistType.MASTER) {
throw new shaka.util.Error(
shaka.util.Error.Severity.CRITICAL,
shaka.util.Error.Category.MANIFEST,
shaka.util.Error.Code.HLS_MASTER_PLAYLIST_NOT_PROVIDED);
}
/** @type {!Array.<!shaka.hls.Tag>} */
const variablesTags = Utils.filterTagsByName(playlist.tags, 'EXT-X-DEFINE');
this.parseMasterVariables_(variablesTags);
/** @type {!Array.<!shaka.hls.Tag>} */
const mediaTags = Utils.filterTagsByName(playlist.tags, 'EXT-X-MEDIA');
/** @type {!Array.<!shaka.hls.Tag>} */
const variantTags = Utils.filterTagsByName(
playlist.tags, 'EXT-X-STREAM-INF');
this.parseCodecs_(variantTags);
/** @type {!Array.<!shaka.hls.Tag>} */
const sesionDataTags =
Utils.filterTagsByName(playlist.tags, 'EXT-X-SESSION-DATA');
for (const tag of sesionDataTags) {
const id = tag.getAttributeValue('DATA-ID');
const uri = tag.getAttributeValue('URI');
const language = tag.getAttributeValue('LANGUAGE');
const value = tag.getAttributeValue('VALUE');
const data = (new Map()).set('id', id);
if (uri) {
data.set('uri',
shaka.hls.Utils.constructAbsoluteUri(this.masterPlaylistUri_, uri));
}
if (language) {
data.set('language', language);
}
if (value) {
data.set('value', value);
}
const event = new shaka.util.FakeEvent('sessiondata', data);
if (this.playerInterface_) {
this.playerInterface_.onEvent(event);
}
}
// Parse audio and video media tags first, so that we can extract segment
// start time from audio/video streams and reuse for text streams.
await this.createStreamInfosFromMediaTags_(mediaTags);
this.parseClosedCaptions_(mediaTags);
const variants = await this.createVariantsForTags_(variantTags);
const textStreams = await this.parseTexts_(mediaTags);
// Make sure that the parser has not been destroyed.
if (!this.playerInterface_) {
throw new shaka.util.Error(
shaka.util.Error.Severity.CRITICAL,
shaka.util.Error.Category.PLAYER,
shaka.util.Error.Code.OPERATION_ABORTED);
}
if (this.aesEncrypted_ && variants.length == 0) {
// We do not support AES-128 encryption with HLS yet. Variants is null
// when the playlist is encrypted with AES-128.
shaka.log.info('No stream is created, because we don\'t support AES-128',
'encryption yet');
throw new shaka.util.Error(
shaka.util.Error.Severity.CRITICAL,
shaka.util.Error.Category.MANIFEST,
shaka.util.Error.Code.HLS_AES_128_ENCRYPTION_NOT_SUPPORTED);
}
// Find the min and max timestamp of the earliest segment in all streams.
// Find the minimum duration of all streams as well.
let minFirstTimestamp = Infinity;
let minDuration = Infinity;
for (const streamInfo of this.uriToStreamInfosMap_.values()) {
minFirstTimestamp =
Math.min(minFirstTimestamp, streamInfo.minTimestamp);
if (streamInfo.stream.type != 'text') {
minDuration = Math.min(minDuration,
streamInfo.maxTimestamp - streamInfo.minTimestamp);
}
}
// This assert is our own sanity check.
goog.asserts.assert(this.presentationTimeline_ == null,
'Presentation timeline created early!');
this.createPresentationTimeline_();
// This assert satisfies the compiler that it is not null for the rest of
// the method.
goog.asserts.assert(this.presentationTimeline_,
'Presentation timeline not created!');
if (this.isLive_()) {
// The HLS spec (RFC 8216) states in 6.3.4:
// "the client MUST wait for at least the target duration before
// attempting to reload the Playlist file again".
// For LL-HLS, the server must add a new partial segment to the Playlist
// every part target duration.
this.updatePlaylistDelay_ = this.minTargetDuration_;
// The spec says nothing much about seeking in live content, but Safari's
// built-in HLS implementation does not allow it. Therefore we will set
// the availability window equal to the presentation delay. The player
// will be able to buffer ahead three segments, but the seek window will
// be zero-sized.
const PresentationType = shaka.hls.HlsParser.PresentationType_;
if (this.presentationType_ == PresentationType.LIVE) {
// This defaults to the presentation delay, which has the effect of
// making the live stream unseekable. This is consistent with Apple's
// HLS implementation.
let segmentAvailabilityDuration = this.presentationTimeline_.getDelay();
// The app can override that with a longer duration, to allow seeking.
if (!isNaN(this.config_.availabilityWindowOverride)) {
segmentAvailabilityDuration = this.config_.availabilityWindowOverride;
}
this.presentationTimeline_.setSegmentAvailabilityDuration(
segmentAvailabilityDuration);
}
} else {
// For VOD/EVENT content, offset everything back to 0.
// Use the minimum timestamp as the offset for all streams.
// Use the minimum duration as the presentation duration.
this.presentationTimeline_.setDuration(minDuration);
// Use a negative offset to adjust towards 0.
this.presentationTimeline_.offset(-minFirstTimestamp);
for (const streamInfo of this.uriToStreamInfosMap_.values()) {
// The segments were created with actual media times, rather than
// presentation-aligned times, so offset them all now.
streamInfo.stream.segmentIndex.offset(-minFirstTimestamp);
// Finally, fit the segments to the playlist duration.
streamInfo.stream.segmentIndex.fit(/* periodStart= */ 0, minDuration);
}
}
// Now that the content has been fit, notify segments.
this.segmentsToNotifyByStream_ = [];
const streamsToNotify = [];
for (const variant of variants) {
for (const stream of [variant.video, variant.audio]) {
if (stream) {
streamsToNotify.push(stream);
}
}
}
await Promise.all(streamsToNotify.map(async (stream) => {
await stream.createSegmentIndex();
}));
for (const stream of streamsToNotify) {
this.segmentsToNotifyByStream_.push(stream.segmentIndex.references);
}
this.notifySegments_();
// This asserts that the live edge is being calculated from segment times.
// For VOD and event streams, this check should still pass.
goog.asserts.assert(
!this.presentationTimeline_.usingPresentationStartTime(),
'We should not be using the presentation start time in HLS!');
this.manifest_ = {
presentationTimeline: this.presentationTimeline_,
variants,
textStreams,
imageStreams: [],
offlineSessionIds: [],
minBufferTime: 0,
};
this.playerInterface_.makeTextStreamsForClosedCaptions(this.manifest_);
}
/**
* Get the variables of each variant tag, and store in a map.
* @param {!Array.<!shaka.hls.Tag>} tags Variant tags from the playlist.
* @private
*/
parseMasterVariables_(tags) {
for (const variableTag of tags) {
const name = variableTag.getAttributeValue('NAME');
const value = variableTag.getAttributeValue('VALUE');
if (name && value) {
if (!this.globalVariables_.has(name)) {
this.globalVariables_.set(name, value);
}
}
}
}
/**
* Get the variables of each variant tag, and store in a map.
* @param {!Array.<!shaka.hls.Tag>} tags Variant tags from the playlist.
* @return {!Map.<string, string>}
* @private
*/
parseMediaVariables_(tags) {
const mediaVariables = new Map();
for (const variableTag of tags) {
const name = variableTag.getAttributeValue('NAME');
const value = variableTag.getAttributeValue('VALUE');
const mediaImport = variableTag.getAttributeValue('IMPORT');
if (name && value) {
mediaVariables.set(name, value);
}
if (mediaImport) {
const globalValue = this.globalVariables_.get(mediaImport);
if (globalValue) {
mediaVariables.set(mediaImport, globalValue);
}
}
}
return mediaVariables;
}
/**
* Get the codecs of each variant tag, and store in a map from
* audio/video/subtitle group id to the codecs arraylist.
* @param {!Array.<!shaka.hls.Tag>} tags Variant tags from the playlist.
* @private
*/
parseCodecs_(tags) {
const ContentType = shaka.util.ManifestParserUtils.ContentType;
for (const variantTag of tags) {
const audioGroupId = variantTag.getAttributeValue('AUDIO');
const videoGroupId = variantTag.getAttributeValue('VIDEO');
const subGroupId = variantTag.getAttributeValue('SUBTITLES');
const allCodecs = this.getCodecsForVariantTag_(variantTag);
if (subGroupId) {
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 = shaka.util.ManifestParserUtils.guessCodecs(
ContentType.AUDIO, allCodecs);
this.groupIdToCodecsMap_.set(audioGroupId, codecs);
}
if (videoGroupId) {
const codecs = shaka.util.ManifestParserUtils.guessCodecs(
ContentType.VIDEO, allCodecs);
this.groupIdToCodecsMap_.set(videoGroupId, codecs);
}
}
}
/**
* Parse Subtitles and Closed Captions from 'EXT-X-MEDIA' tags.
* Create text streams for Subtitles, but not Closed Captions.
*
* @param {!Array.<!shaka.hls.Tag>} mediaTags Media tags from the playlist.
* @return {!Promise.<!Array.<!shaka.extern.Stream>>}
* @private
*/
async parseTexts_(mediaTags) {
// Create text stream for each Subtitle media tag.
const subtitleTags =
shaka.hls.Utils.filterTagsByType(mediaTags, 'SUBTITLES');
const textStreamPromises = subtitleTags.map(async (tag) => {
const disableText = this.config_.disableText;
if (disableText) {
return null;
}
try {
const streamInfo = await this.createStreamInfoFromMediaTag_(tag);
goog.asserts.assert(
streamInfo, 'Should always have a streamInfo for text');
return streamInfo.stream;
} catch (e) {
if (this.config_.hls.ignoreTextStreamFailures) {
return null;
}
throw e;
}
});
const textStreams = await Promise.all(textStreamPromises);
// Set the codecs for text streams.
for (const tag of subtitleTags) {
const groupId = tag.getRequiredAttrValue('GROUP-ID');
const codecs = this.groupIdToCodecsMap_.get(groupId);
if (codecs) {
const textStreamInfos = this.groupIdToStreamInfosMap_.get(groupId);
if (textStreamInfos) {
for (const textStreamInfo of textStreamInfos) {
textStreamInfo.stream.codecs = codecs;
}
}
}
}
// Do not create text streams for Closed captions.
return textStreams.filter((s) => s);
}
/**
* @param {!Array.<!shaka.hls.Tag>} mediaTags Media tags from the playlist.
* @private
*/
async createStreamInfosFromMediaTags_(mediaTags) {
// Filter out subtitles and media tags without uri.
mediaTags = mediaTags.filter((tag) => {
const uri = tag.getAttributeValue('URI') || '';
const type = tag.getAttributeValue('TYPE');
return type != 'SUBTITLES' && uri != '';
});
// Create stream info for each audio / video media tag.
// Wait for the first stream info created, so that the start time is fetched
// and can be reused.
if (mediaTags.length) {
await this.createStreamInfoFromMediaTag_(mediaTags[0]);
}
const promises = mediaTags.slice(1).map((tag) => {
return this.createStreamInfoFromMediaTag_(tag);
});
await Promise.all(promises);
}
/**
* @param {!Array.<!shaka.hls.Tag>} tags Variant tags from the playlist.
* @return {!Promise.<!Array.<!shaka.extern.Variant>>}
* @private
*/
async createVariantsForTags_(tags) {
// Create variants for each variant tag.
const variantsPromises = tags.map(async (tag) => {
const frameRate = tag.getAttributeValue('FRAME-RATE');
const bandwidth = Number(tag.getAttributeValue('AVERAGE-BANDWIDTH')) ||
Number(tag.getRequiredAttrValue('BANDWIDTH'));
const resolution = tag.getAttributeValue('RESOLUTION');
const [width, height] = resolution ? resolution.split('x') : [null, null];
const videoRange = tag.getAttributeValue('VIDEO-RANGE');
const streamInfos = await this.createStreamInfosForVariantTag_(tag,
resolution, frameRate);
if (streamInfos) {
goog.asserts.assert(streamInfos.audio.length ||
streamInfos.video.length, 'We should have created a stream!');
return this.createVariants_(
streamInfos.audio,
streamInfos.video,
bandwidth,
width,
height,
frameRate,
videoRange);
}
// We do not support AES-128 encryption with HLS yet. If the streamInfos
// is null because of AES-128 encryption, do not create variants for that.
return [];
});
const allVariants = await Promise.all(variantsPromises);
let variants = allVariants.reduce(shaka.util.Functional.collapseArrays, []);
// Filter out null variants.
variants = variants.filter((variant) => variant != null);
return variants;
}
/**
* Create audio and video streamInfos from an 'EXT-X-STREAM-INF' tag and its
* related media tags.
*
* @param {!shaka.hls.Tag} tag
* @param {?string} resolution
* @param {?string} frameRate
* @return {!Promise.<?shaka.hls.HlsParser.StreamInfos>}
* @private
*/
async createStreamInfosForVariantTag_(tag, resolution, frameRate) {
const ContentType = shaka.util.ManifestParserUtils.ContentType;
/** @type {!Array.<string>} */
let allCodecs = this.getCodecsForVariantTag_(tag);
const audioGroupId = tag.getAttributeValue('AUDIO');
const videoGroupId = tag.getAttributeValue('VIDEO');
goog.asserts.assert(audioGroupId == null || videoGroupId == null,
'Unexpected: both video and audio described by media tags!');
const groupId = audioGroupId || videoGroupId;
const streamInfos =
(groupId && this.groupIdToStreamInfosMap_.has(groupId)) ?
this.groupIdToStreamInfosMap_.get(groupId) : [];
/** @type {shaka.hls.HlsParser.StreamInfos} */
const res = {
audio: audioGroupId ? streamInfos : [],
video: videoGroupId ? streamInfos : [],
};
// Make an educated guess about the stream type.
shaka.log.debug('Guessing stream type for', tag.toString());
let type;
let ignoreStream = false;
// The Microsoft HLS manifest generators will make audio-only variants
// that link to their URI both directly and through an audio tag.
// In that case, ignore the local URI and use the version in the
// AUDIO tag, so you inherit its language.
// As an example, see the manifest linked in issue #860.
const streamURI = tag.getRequiredAttrValue('URI');
const hasSameUri = res.audio.find((audio) => {
return audio && audio.verbatimMediaPlaylistUri == streamURI;
});
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,
// and no video codec, so it should be audio.
type = ContentType.AUDIO;
shaka.log.debug('Guessing audio-only.');
} else if (!streamInfos.length && audioCodecs && videoCodecs) {
// There are both audio and video codecs, so assume multiplexed content.
// Note that the default used when CODECS is missing assumes multiple
// (and therefore multiplexed).
// Recombine the codec strings into one so that MediaSource isn't
// lied to later. (That would trigger an error in Chrome.)
shaka.log.debug('Guessing multiplexed audio+video.');
type = ContentType.VIDEO;
allCodecs = [[videoCodecs, audioCodecs].join(',')];
} else if (res.audio.length && hasSameUri) {
shaka.log.debug('Guessing audio-only.');
type = ContentType.AUDIO;
ignoreStream = true;
} else if (res.video.length) {
// There are associated video streams. Assume this is audio.
shaka.log.debug('Guessing audio-only.');
type = ContentType.AUDIO;
} else {
shaka.log.debug('Guessing video-only.');
type = ContentType.VIDEO;
}
let streamInfo;
if (!ignoreStream) {
streamInfo =
await this.createStreamInfoFromVariantTag_(tag, allCodecs, type);
}
if (streamInfo) {
res[streamInfo.stream.type] = [streamInfo];
} else if (streamInfo === null) {
// Triple-equals for undefined.
shaka.log.debug('streamInfo is null');
return null;
}
this.filterLegacyCodecs_(res);
return res;
}
/**
* Get the codecs from the 'EXT-X-STREAM-INF' tag.
*
* @param {!shaka.hls.Tag} tag
* @return {!Array.<string>} codecs
* @private
*/
getCodecsForVariantTag_(tag) {
// These are the default codecs to assume if none are specified.
// The video codec is H.264, with baseline profile and level 3.0.
// http://blog.pearce.org.nz/2013/11/what-does-h264avc1-codecs-parameters.html
// The audio codec is "low-complexity" AAC.
const defaultCodecsArray = [];
if (!this.config_.disableVideo) {
defaultCodecsArray.push('avc1.42E01E');
}
if (!this.config_.disableAudio) {
defaultCodecsArray.push('mp4a.40.2');
}
const defaultCodecs = defaultCodecsArray.join(',');
const codecsString = tag.getAttributeValue('CODECS', defaultCodecs);
// Strip out internal whitespace while splitting on commas:
/** @type {!Array.<string>} */
const codecs = codecsString.split(/\s*,\s*/);
// Filter out duplicate codecs.
const seen = new Set();
const ret = [];
for (const codec of codecs) {
// HLS says the CODECS field needs to include all codecs that appear in
// the content. This means that if the content changes profiles, it should
// include both. Since all known browsers support changing profiles
// without any other work, just ignore them. See also:
// https://github.com/shaka-project/shaka-player/issues/1817
const shortCodec = shaka.util.MimeUtils.getCodecBase(codec);
if (!seen.has(shortCodec)) {
ret.push(codec);
seen.add(shortCodec);
} else {
shaka.log.debug('Ignoring duplicate codec');
}
}
return ret;
}
/**
* Get the channel count information for an HLS audio track.
* CHANNELS specifies an ordered, "/" separated list of parameters.
* If the type is audio, the first parameter will be a decimal integer
* specifying the number of independent, simultaneous audio channels.
* No other channels parameters are currently defined.
*
* @param {!shaka.hls.Tag} tag
* @return {?number}
* @private
*/
getChannelsCount_(tag) {
const channels = tag.getAttributeValue('CHANNELS');
if (!channels) {
return null;
}
const channelcountstring = channels.split('/')[0];
const count = parseInt(channelcountstring, 10);
return count;
}
/**
* Get the spatial audio information for an HLS audio track.
* In HLS the channels field indicates the number of audio channels that the
* stream has (eg: 2). In the case of Dolby Atmos, the complexity is
* expressed with the number of channels followed by the word JOC
* (eg: 16/JOC), so 16 would be the number of channels (eg: 7.3.6 layout),
* and JOC indicates that the stream has spatial audio.
* @see https://developer.apple.com/documentation/http_live_streaming/hls_authoring_specification_for_apple_devices/hls_authoring_specification_for_apple_devices_appendixes
*
* @param {!shaka.hls.Tag} tag
* @return {boolean}
* @private
*/
isSpatialAudio_(tag) {
const channels = tag.getAttributeValue('CHANNELS');
if (!channels) {
return false;
}
return channels.includes('/JOC');
}
/**
* Get the closed captions map information for the EXT-X-STREAM-INF tag, to
* create the stream info.
* @param {!shaka.hls.Tag} tag
* @param {string} type
* @return {Map.<string, string>} closedCaptions
* @private
*/
getClosedCaptions_(tag, type) {
const ContentType = shaka.util.ManifestParserUtils.ContentType;
// The attribute of closed captions is optional, and the value may be
// 'NONE'.
const closedCaptionsAttr = tag.getAttributeValue('CLOSED-CAPTIONS');
// EXT-X-STREAM-INF tags may have CLOSED-CAPTIONS attributes.
// The value can be either a quoted-string or an enumerated-string with
// the value NONE. If the value is a quoted-string, it MUST match the
// value of the GROUP-ID attribute of an EXT-X-MEDIA tag elsewhere in the
// Playlist whose TYPE attribute is CLOSED-CAPTIONS.
if (type == ContentType.VIDEO && closedCaptionsAttr &&
closedCaptionsAttr != 'NONE') {
return this.groupIdToClosedCaptionsMap_.get(closedCaptionsAttr);
}
return null;
}
/**
* Get the language value.
*
* @param {!shaka.hls.Tag} tag
* @return {string}
* @private
*/
getLanguage_(tag) {
const LanguageUtils = shaka.util.LanguageUtils;
const languageValue = tag.getAttributeValue('LANGUAGE') || 'und';
return LanguageUtils.normalize(languageValue);
}
/**
* Get the type value.
* Shaka recognizes the content types 'audio', 'video' and 'text'.
* The HLS 'subtitles' type needs to be mapped to 'text'.
* @param {!shaka.hls.Tag} tag
* @return {string}
* @private
*/
getType_(tag) {
let type = tag.getRequiredAttrValue('TYPE').toLowerCase();
if (type == 'subtitles') {
type = shaka.util.ManifestParserUtils.ContentType.TEXT;
}
return type;
}
/**
* Filters out unsupported codec strings from an array of stream infos.
* @param {shaka.hls.HlsParser.StreamInfos} streamInfos
* @private
*/
filterLegacyCodecs_(streamInfos) {
for (const streamInfo of streamInfos.audio.concat(streamInfos.video)) {
if (!streamInfo) {
continue;
}
let codecs = streamInfo.stream.codecs.split(',');
codecs = codecs.filter((codec) => {
// mp4a.40.34 is a nonstandard codec string that is sometimes used in
// HLS for legacy reasons. It is not recognized by non-Apple MSE.
// See https://bugs.chromium.org/p/chromium/issues/detail?id=489520
// Therefore, ignore this codec string.
return codec != 'mp4a.40.34';
});
streamInfo.stream.codecs = codecs.join(',');
}
}
/**
* @param {!Array.<shaka.hls.HlsParser.StreamInfo>} audioInfos
* @param {!Array.<shaka.hls.HlsParser.StreamInfo>} videoInfos
* @param {number} bandwidth
* @param {?string} width
* @param {?string} height
* @param {?string} frameRate
* @param {?string} videoRange
* @return {!Array.<!shaka.extern.Variant>}
* @private
*/
createVariants_(
audioInfos, videoInfos, bandwidth, width, height, frameRate, videoRange) {
const ContentType = shaka.util.ManifestParserUtils.ContentType;
const DrmEngine = shaka.media.DrmEngine;
for (const info of videoInfos) {
this.addVideoAttributes_(
info.stream, width, height, frameRate, videoRange);
}
// In case of audio-only or video-only content or the audio/video is
// disabled by the config, we create an array of one item containing
// a null. This way, the double-loop works for all kinds of content.
// NOTE: we currently don't have support for audio-only content.
const disableAudio = this.config_.disableAudio;
if (!audioInfos.length || disableAudio) {
audioInfos = [null];
}
const disableVideo = this.config_.disableVideo;
if (!videoInfos.length || disableVideo) {
videoInfos = [null];
}
const variants = [];
for (const audioInfo of audioInfos) {
for (const videoInfo of videoInfos) {
const audioStream = audioInfo ? audioInfo.stream : null;
const videoStream = videoInfo ? videoInfo.stream : null;
const audioDrmInfos = audioInfo ? audioInfo.stream.drmInfos : null;
const videoDrmInfos = videoInfo ? videoInfo.stream.drmInfos : null;
const videoStreamUri =
videoInfo ? videoInfo.verbatimMediaPlaylistUri : '';
const audioStreamUri =
audioInfo ? audioInfo.verbatimMediaPlaylistUri : '';
const variantUriKey = videoStreamUri + ' - ' + audioStreamUri;
if (audioStream && videoStream) {
if (!DrmEngine.areDrmCompatible(audioDrmInfos, videoDrmInfos)) {
shaka.log.warning(
'Incompatible DRM info in HLS variant. Skipping.');
continue;
}
}
if (this.variantUriSet_.has(variantUriKey)) {
// This happens when two variants only differ in their text streams.
shaka.log.debug(
'Skipping variant which only differs in text streams.');
continue;
}
// Since both audio and video are of the same type, this assertion will
// catch certain mistakes at runtime that the compiler would miss.
goog.asserts.assert(!audioStream ||
audioStream.type == ContentType.AUDIO, 'Audio parameter mismatch!');
goog.asserts.assert(!videoStream ||
videoStream.type == ContentType.VIDEO, 'Video parameter mismatch!');
const variant = {
id: this.globalId_++,
language: audioStream ? audioStream.language : 'und',
primary: (!!audioStream && audioStream.primary) ||
(!!videoStream && videoStream.primary),
audio: audioStream,
video: videoStream,
bandwidth,
allowedByApplication: true,
allowedByKeySystem: true,
decodingInfos: [],
};
variants.push(variant);
this.variantUriSet_.add(variantUriKey);
}
}
return variants;
}
/**
* Parses an array of EXT-X-MEDIA tags, then stores the values of all tags
* with TYPE="CLOSED-CAPTIONS" into a map of group id to closed captions.
*
* @param {!Array.<!shaka.hls.Tag>} mediaTags
* @private
*/
parseClosedCaptions_(mediaTags) {
const closedCaptionsTags =
shaka.hls.Utils.filterTagsByType(mediaTags, 'CLOSED-CAPTIONS');
for (const tag of closedCaptionsTags) {
goog.asserts.assert(tag.name == 'EXT-X-MEDIA',
'Should only be called on media tags!');
const language = this.getLanguage_(tag);
// The GROUP-ID value is a quoted-string that specifies the group to which
// the Rendition belongs.
const groupId = tag.getRequiredAttrValue('GROUP-ID');
// The value of INSTREAM-ID is a quoted-string that specifies a Rendition
// within the segments in the Media Playlist. This attribute is REQUIRED
// if the TYPE attribute is CLOSED-CAPTIONS.
const instreamId = tag.getRequiredAttrValue('INSTREAM-ID');
if (!this.groupIdToClosedCaptionsMap_.get(groupId)) {
this.groupIdToClosedCaptionsMap_.set(groupId, new Map());
}
this.groupIdToClosedCaptionsMap_.get(groupId).set(instreamId, language);
}
}
/**
* Parse EXT-X-MEDIA media tag into a Stream object.
*
* @param {shaka.hls.Tag} tag
* @return {!Promise.<?shaka.hls.HlsParser.StreamInfo>}
* @private
*/
async createStreamInfoFromMediaTag_(tag) {
goog.asserts.assert(tag.name == 'EXT-X-MEDIA',
'Should only be called on media tags!');
const groupId = tag.getRequiredAttrValue('GROUP-ID');
let codecs = '';
/** @type {string} */
const type = this.getType_(tag);
// Text does not require a codec.
if (type != shaka.util.ManifestParserUtils.ContentType.TEXT && groupId &&
this.groupIdToCodecsMap_.has(groupId)) {
codecs = this.groupIdToCodecsMap_.get(groupId);
}
const verbatimMediaPlaylistUri = this.variableSubstitution_(
tag.getRequiredAttrValue('URI'), this.globalVariables_);
// Check if the stream has already been created as part of another Variant
// and return it if it has.
if (this.uriToStreamInfosMap_.has(verbatimMediaPlaylistUri)) {
return this.uriToStreamInfosMap_.get(verbatimMediaPlaylistUri);
}
const language = this.getLanguage_(tag);
const name = tag.getAttributeValue('NAME');
// NOTE: According to the HLS spec, "DEFAULT=YES" requires "AUTOSELECT=YES".
// However, we don't bother to validate "AUTOSELECT", since we don't
// actually use it in our streaming model, and we treat everything as
// "AUTOSELECT=YES". A value of "AUTOSELECT=NO" would imply that it may
// only be selected explicitly by the user, and we don't have a way to
// represent that in our model.
const defaultAttrValue = tag.getAttributeValue('DEFAULT');
const primary = defaultAttrValue == 'YES';
const channelsCount = type == 'audio' ? this.getChannelsCount_(tag) : null;
const spatialAudio = type == 'audio' ? this.isSpatialAudio_(tag) : false;
const characteristics = tag.getAttributeValue('CHARACTERISTICS');
const forcedAttrValue = tag.getAttributeValue('FORCED');
const forced = forcedAttrValue == 'YES';
// TODO: Should we take into account some of the currently ignored
// attributes: INSTREAM-ID, Attribute descriptions: https://bit.ly/2lpjOhj
const streamInfo = await this.createStreamInfo_(
verbatimMediaPlaylistUri, codecs, type, language, primary, name,
channelsCount, /* closedCaptions= */ null, characteristics, forced,
spatialAudio);
if (this.groupIdToStreamInfosMap_.has(groupId)) {
this.groupIdToStreamInfosMap_.get(groupId).push(streamInfo);
} else {
this.groupIdToStreamInfosMap_.set(groupId, [streamInfo]);
}
if (streamInfo == null) {
return null;
}
// TODO: This check is necessary because of the possibility of multiple
// calls to createStreamInfoFromMediaTag_ before either has resolved.
if (this.uriToStreamInfosMap_.has(verbatimMediaPlaylistUri)) {
return this.uriToStreamInfosMap_.get(verbatimMediaPlaylistUri);
}
this.uriToStreamInfosMap_.set(verbatimMediaPlaylistUri, streamInfo);
return streamInfo;
}
/**
* Parse an EXT-X-STREAM-INF media tag into a Stream object.
*
* @param {!shaka.hls.Tag} tag
* @param {!Array.<string>} allCodecs
* @param {string} type
* @return {!Promise.<?shaka.hls.HlsParser.StreamInfo>}
* @private
*/
async createStreamInfoFromVariantTag_(tag, allCodecs, type) {
goog.asserts.assert(tag.name == 'EXT-X-STREAM-INF',
'Should only be called on variant tags!');
const verbatimMediaPlaylistUri = this.variableSubstitution_(
tag.getRequiredAttrValue('URI'), this.globalVariables_);
if (this.uriToStreamInfosMap_.has(verbatimMediaPlaylistUri)) {
return this.uriToStreamInfosMap_.get(verbatimMediaPlaylistUri);
}
const closedCaptions = this.getClosedCaptions_(tag, type);
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,
/* characteristics= */ null, /* forced= */ false,
/* spatialAudio= */ false);
if (streamInfo == null) {
return null;
}
// TODO: This check is necessary because of the possibility of multiple
// calls to createStreamInfoFromVariantTag_ before either has resolved.
if (this.uriToStreamInfosMap_.has(verbatimMediaPlaylistUri)) {
return this.uriToStreamInfosMap_.get(verbatimMediaPlaylistUri);
}
this.uriToStreamInfosMap_.set(verbatimMediaPlaylistUri, streamInfo);
return streamInfo;
}
/**
* @param {string} verbatimMediaPlaylistUri
* @param {string} codecs
* @param {string} type
* @param {string} language
* @param {boolean} primary
* @param {?string} name
* @param {?number} channelsCount
* @param {Map.<string, string>} closedCaptions
* @param {?string} characteristics
* @param {boolean} forced
* @param {boolean} spatialAudio
* @return {!Promise.<?shaka.hls.HlsParser.StreamInfo>}
* @private
*/
async createStreamInfo_(verbatimMediaPlaylistUri, codecs, type, language,
primary, name, channelsCount, closedCaptions, characteristics, forced,
spatialAudio) {
// TODO: Refactor, too many parameters
let absoluteMediaPlaylistUri = shaka.hls.Utils.constructAbsoluteUri(
this.masterPlaylistUri_, verbatimMediaPlaylistUri);
const response = await this.requestManifest_(absoluteMediaPlaylistUri);
// Record the final URI after redirects.
absoluteMediaPlaylistUri = response.uri;
// Record the redirected, final URI of this media playlist when we parse it.
/** @type {!shaka.hls.Playlist} */
const playlist = this.manifestTextParser_.parsePlaylist(
response.data, absoluteMediaPlaylistUri);
if (playlist.type != shaka.hls.PlaylistType.MEDIA) {
// EXT-X-MEDIA tags should point to media playlists.
throw new shaka.util.Error(
shaka.util.Error.Severity.CRITICAL,
shaka.util.Error.Category.MANIFEST,
shaka.util.Error.Code.HLS_INVALID_PLAYLIST_HIERARCHY);
}
/** @type {!Array.<!shaka.hls.Tag>} */
const drmTags = [];
if (playlist.segments) {
for (const segment of playlist.segments) {
const segmentKeyTags = shaka.hls.Utils.filterTagsByName(segment.tags,
'EXT-X-KEY');
drmTags.push(...segmentKeyTags);
}
}
let encrypted = false;
/** @type {!Array.<shaka.extern.DrmInfo>}*/
const drmInfos = [];
const keyIds = new Set();
// TODO: May still need changes to support key rotation.
for (const drmTag of drmTags) {
const method = drmTag.getRequiredAttrValue('METHOD');
if (method != 'NONE') {
encrypted = true;
// We do not support AES-128 encryption with HLS yet. So, do not create
// StreamInfo for the playlist encrypted with AES-128.
// TODO: Remove the error message once we add support for AES-128.
if (method == 'AES-128') {
shaka.log.warning('Unsupported HLS Encryption', method);
this.aesEncrypted_ = true;
return null;
}
const keyFormat = drmTag.getRequiredAttrValue('KEYFORMAT');
const drmParser =
shaka.hls.HlsParser.KEYFORMATS_TO_DRM_PARSERS_[keyFormat];
const drmInfo = drmParser ? drmParser(drmTag) : null;
if (drmInfo) {
if (drmInfo.keyIds) {
for (const keyId of drmInfo.keyIds) {
keyIds.add(keyId);
}
}
drmInfos.push(drmInfo);
} else {
shaka.log.warning('Unsupported HLS KEYFORMAT', keyFormat);
}
}
}
if (encrypted && !drmInfos.length) {
throw new shaka.util.Error(
shaka.util.Error.Severity.CRITICAL,
shaka.util.Error.Category.MANIFEST,
shaka.util.Error.Code.HLS_KEYFORMATS_NOT_SUPPORTED);
}
/** @type {!Array.<!shaka.hls.Tag>} */
const variablesTags = shaka.hls.Utils.filterTagsByName(playlist.tags,
'EXT-X-DEFINE');
const mediaVariables = this.parseMediaVariables_(variablesTags);
goog.asserts.assert(playlist.segments != null,
'Media playlist should have segments!');
this.determinePresentationType_(playlist);
/** @type {string} */
const mimeType = await this.guessMimeType_(type, codecs, playlist,
mediaVariables);
// MediaSource expects no codec strings combined with raw formats.
// TODO(#2337): Instead, create a Stream flag indicating a raw format.
if (shaka.hls.HlsParser.RAW_FORMATS_.includes(mimeType)) {
codecs = '';
}
/** @type {!Map.<number, number>} */
const mediaSequenceToStartTime = new Map();
/**
* A map of a discontinuity sequence number, to the first segment's media
* sequence number with the discontinuity sequence number.
* Key: the discontinuity sequence number of a few segments
* Value: the first segment's media sequence number of the segments with
* this discontinuity sequence number.
* Used to get the discontinuity sequence number with playlist delta
* updates with lowLatencyMode enabled.
* {!Map.<number, number>}
*/
const discontinuityToMediaSequence = new Map();
let segments;
try {
segments = await this.createSegments_(verbatimMediaPlaylistUri,
playlist, type, mimeType, mediaSequenceToStartTime, mediaVariables,
discontinuityToMediaSequence);
} catch (error) {
if (error.code == shaka.util.Error.Code.HLS_INTERNAL_SKIP_STREAM) {
shaka.log.alwaysWarn('Skipping unsupported HLS stream',
mimeType, verbatimMediaPlaylistUri);
return null;
}
throw error;
}
const minTimestamp = segments[0].startTime;
const lastEndTime = segments[segments.length - 1].endTime;
/** @type {!shaka.media.SegmentIndex} */
const segmentIndex = new shaka.media.SegmentIndex(segments);
const kind = (type == shaka.util.ManifestParserUtils.ContentType.TEXT) ?
shaka.util.ManifestParserUtils.TextStreamKind.SUBTITLE : undefined;
const roles = [];
if (characteristics) {
for (const characteristic of characteristics.split(',')) {
roles.push(characteristic);
}
}
const serverControlTag = shaka.hls.Utils.getFirstTagWithName(
playlist.tags, 'EXT-X-SERVER-CONTROL');
const canSkipSegments = serverControlTag ?
serverControlTag.getAttribute('CAN-SKIP-UNTIL') != null : false;
/** @type {shaka.extern.Stream} */
const stream = {
id: this.globalId_++,
originalId: name,
createSegmentIndex: () => Promise.resolve(),
segmentIndex,
mimeType,
codecs,
kind,
encrypted,
drmInfos,
keyIds,
language,
label: name, // For historical reasons, since before "originalId".
type,
primary,
// TODO: trick mode
trickModeVideo: null,
emsgSchemeIdUris: null,
frameRate: undefined,
pixelAspectRatio: undefined,
width: undefined,
height: undefined,
bandwidth: undefined,
roles: roles,
forced: forced,
channelsCount,
audioSamplingRate: null,
spatialAudio: spatialAudio,
closedCaptions,
hdr: undefined,
tilesLayout: undefined,
};
return {
stream,
verbatimMediaPlaylistUri,
absoluteMediaPlaylistUri,
minTimestamp,
maxTimestamp: lastEndTime,
mediaSequenceToStartTime,
discontinuityToMediaSequence,
canSkipSegments,
};
}
/**
* @param {!shaka.hls.Playlist} playlist
* @private
*/
determinePresentationType_(playlist) {
const PresentationType = shaka.hls.HlsParser.PresentationType_;
const presentationTypeTag =
shaka.hls.Utils.getFirstTagWithName(playlist.tags,
'EXT-X-PLAYLIST-TYPE');
const endListTag =
shaka.hls.Utils.getFirstTagWithName(playlist.tags, 'EXT-X-ENDLIST');
const isVod = (presentationTypeTag && presentationTypeTag.value == 'VOD') ||
endListTag;
const isEvent = presentationTypeTag &&
presentationTypeTag.value == 'EVENT' && !isVod;
const isLive = !isVod && !isEvent;
if (isVod) {
this.setPresentationType_(PresentationType.VOD);
} else {
// If it's not VOD, it must be presentation type LIVE or an ongoing EVENT.
if (isLive) {
this.setPresentationType_(PresentationType.LIVE);
} else {
this.setPresentationType_(PresentationType.EVENT);
}
const targetDurationTag = this.getRequiredTag_(playlist.tags,
'EXT-X-TARGETDURATION');
const targetDuration = Number(targetDurationTag.value);
const partialTargetDurationTag =
shaka.hls.Utils.getFirstTagWithName(playlist.tags, 'EXT-X-PART-INF');
// According to the HLS spec, updates should not happen more often than
// once in targetDuration. It also requires us to only update the active
// variant. We might implement that later, but for now every variant
// will be updated. To get the update period, choose the smallest
// targetDuration value across all playlists.
// 1. Update the shortest one to use as update period and segment
// availability time (for LIVE).
if (this.lowLatencyMode_ && partialTargetDurationTag) {
// For low latency streaming, use the partial segment target duration.
this.partialTargetDuration_ = Number(
partialTargetDurationTag.getRequiredAttrValue('PART-TARGET'));
this.minTargetDuration_ = Math.min(
this.partialTargetDuration_, this.minTargetDuration_);
// Get the server-recommended min distance from the live edge.
const serverControlTag = shaka.hls.Utils.getFirstTagWithName(
playlist.tags, 'EXT-X-SERVER-CONTROL');
// Use 'PART-HOLD-BACK' as the presentation delay for low latency mode.
this.lowLatencyPresentationDelay_ = serverControlTag ? Number(
serverControlTag.getRequiredAttrValue('PART-HOLD-BACK')) : 0;
} else {
// For regular HLS, use the target duration of regular segments.
this.minTargetDuration_ = Math.min(
targetDuration, this.minTargetDuration_);
}
// 2. Update the longest target duration if need be to use as a
// presentation delay later.
this.maxTargetDuration_ = Math.max(
targetDuration, this.maxTargetDuration_);
}
}
/**
* @private
*/
createPresentationTimeline_() {
if (this.isLive_()) {
// The live edge will be calculated from segments, so we don't need to
// set a presentation start time. We will assert later that this is
// working as expected.
// The HLS spec (RFC 8216) states in 6.3.3:
//
// "The client SHALL choose which Media Segment to play first ... the
// client SHOULD NOT choose a segment that starts less than three target
// durations from the end of the Playlist file. Doing so can trigger
// playback stalls."
//
// We accomplish this in our DASH-y model by setting a presentation
// delay of configured value, or 3 segments duration if not configured.
// This will be the "live edge" of the presentation.
let presentationDelay;
if (this.config_.defaultPresentationDelay) {
presentationDelay = this.config_.defaultPresentationDelay;
} else if (this.lowLatencyPresentationDelay_) {
presentationDelay = this.lowLatencyPresentationDelay_;
} else {
presentationDelay = this.maxTargetDuration_ * 3;
}
this.presentationTimeline_ = new shaka.media.PresentationTimeline(
/* presentationStartTime= */ 0, /* delay= */ presentationDelay);
this.presentationTimeline_.setStatic(false);
} else {
this.presentationTimeline_ = new shaka.media.PresentationTimeline(
/* presentationStartTime= */ null, /* delay= */ 0);
this.presentationTimeline_.setStatic(true);
}
this.notifySegments_();
}
/**
* Get the InitSegmentReference for a segment if it has a EXT-X-MAP tag.
* @param {string} playlistUri The absolute uri of the media playlist.
* @param {!Array.<!shaka.hls.Tag>} tags Segment tags
* @param {!Map.<string, string>} variables
* @return {shaka.media.InitSegmentReference}
* @private
*/
getInitSegmentReference_(playlistUri, tags, variables) {
/** @type {?shaka.hls.Tag} */
const mapTag = shaka.hls.Utils.getFirstTagWithName(tags, 'EXT-X-MAP');
if (!mapTag) {
return null;
}
// Map tag example: #EXT-X-MAP:URI="main.mp4",BYTERANGE="720@0"
const verbatimInitSegmentUri = mapTag.getRequiredAttrValue('URI');
const absoluteInitSegmentUri = this.variableSubstitution_(
shaka.hls.Utils.constructAbsoluteUri(
playlistUri, verbatimInitSegmentUri),
variables);
const mapTagKey = [
absoluteInitSegmentUri,
mapTag.getAttributeValue('BYTERANGE', ''),
].join('-');
if (!this.mapTagToInitSegmentRefMap_.has(mapTagKey)) {
const initSegmentRef = this.createInitSegmentReference_(
absoluteInitSegmentUri, mapTag);
this.mapTagToInitSegmentRefMap_.set(mapTagKey, initSegmentRef);
}
return this.mapTagToInitSegmentRefMap_.get(mapTagKey);
}
/**
* Create an InitSegmentReference object for the EXT-X-MAP tag in the media
* playlist.
* @param {string} absoluteInitSegmentUri
* @param {!shaka.hls.Tag} mapTag EXT-X-MAP
* @return {!shaka.media.InitSegmentReference}
* @private
*/
createInitSegmentReference_(absoluteInitSegmentUri, mapTag) {
let startByte = 0;
let endByte = null;
const byterange = mapTag.getAttributeValue('BYTERANGE');
// If a BYTERANGE attribute is not specified, the segment consists
// of the entire resource.
if (byterange) {
const blocks = byterange.split('@');
const byteLength = Number(blocks[0]);
startByte = Number(blocks[1]);
endByte = startByte + byteLength - 1;
}
const initSegmentRef = new shaka.media.InitSegmentReference(
() => [absoluteInitSegmentUri],
startByte,
endByte);
return initSegmentRef;
}
/**
* Parses one shaka.hls.Segment object into a shaka.media.SegmentReference.
*
* @param {shaka.media.InitSegmentReference} initSegmentReference
* @param {shaka.media.SegmentReference} previousReference
* @param {!shaka.hls.Segment} hlsSegment
* @param {number} startTime
* @param {number} timestampOffset
* @param {!Map.<string, string>} variables
* @param {string} absoluteMediaPlaylistUri
* @return {!shaka.media.SegmentReference}
* @private
*/
createSegmentReference_(
initSegmentReference, previousReference, hlsSegment, startTime,
timestampOffset, variables, absoluteMediaPlaylistUri) {
const tags = hlsSegment.tags;
const absoluteSegmentUri = this.variableSubstitution_(
hlsSegment.absoluteUri, variables);
const extinfTag =
shaka.hls.Utils.getFirstTagWithName(tags, 'EXTINF');
let endTime = 0;
let startByte = 0;
let endByte = null;
// Create SegmentReferences for the partial segments.
const partialSegmentRefs = [];
if (this.lowLatencyMode_ && hlsSegment.partialSegments.length) {
for (let i = 0; i < hlsSegment.partialSegments.length; i++) {
const item = hlsSegment.partialSegments[i];
const pPreviousReference = i == 0 ?
previousReference : partialSegmentRefs[partialSegmentRefs.length - 1];
const pStartTime = (i == 0) ? startTime : pPreviousReference.endTime;
const pDuration = Number(item.getAttributeValue('DURATION'));
// A preload hinted partial segment doesn't have duration information,
// so its startTime and endTime are the same.
const pEndTime = pStartTime + pDuration;
let pStartByte = 0;
let pEndByte = null;
if (item.name == 'EXT-X-PRELOAD-HINT') {
// A preload hinted partial segment may have byterange start info.
const pByterangeStart = item.getAttributeValue('BYTERANGE-START');
pStartByte = pByterangeStart ? Number(pByterangeStart) : 0;
} else {
const pByterange = item.getAttributeValue('BYTERANGE');
[pStartByte, pEndByte] =
this.parseByteRange_(pPreviousReference, pByterange);
}
const pUri = item.getAttributeValue('URI');
if (!pUri) {
continue;
}
const pAbsoluteUri = shaka.hls.Utils.constructAbsoluteUri(
absoluteMediaPlaylistUri, pUri);
const partial = new shaka.media.SegmentReference(
pStartTime,
pEndTime,
() => [pAbsoluteUri],
pStartByte,
pEndByte,
initSegmentReference,
timestampOffset,
/* appendWindowStart= */ 0,
/* appendWindowEnd= */ Infinity);
partialSegmentRefs.push(partial);
} // for-loop of hlsSegment.partialSegments
} else {
// EXTINF tag must be available if the segment has no partial segments.
if (!extinfTag) {
throw new shaka.util.Error(
shaka.util.Error.Severity.CRITICAL,
shaka.util.Error.Category.MANIFEST,
shaka.util.Error.Code.HLS_REQUIRED_TAG_MISSING, 'EXTINF');
}
}
// If the segment has EXTINF tag, set the segment's end time, start byte
// and end byte based on the duration and byterange information.
// Otherwise, calculate the end time, start / end byte based on its partial
// segments.
// Note that the sum of partial segments durations may be slightly different
// from the parent segment's duration. In this case, use the duration from
// the parent segment tag.
if (extinfTag) {
// The EXTINF tag format is '#EXTINF:<duration>,[<title>]'.
// We're interested in the duration part.
const extinfValues = extinfTag.value.split(',');
const duration = Number(extinfValues[0]);
endTime = startTime + duration;
} else {
endTime = partialSegmentRefs[partialSegmentRefs.length - 1].endTime;
}
// If the segment has EXT-X-BYTERANGE tag, set the start byte and end byte
// base on the byterange information. If segment has no EXT-X-BYTERANGE tag
// and has partial segments, set the start byte and end byte base on the
// partial segments.
const byterangeTag =
shaka.hls.Utils.getFirstTagWithName(tags, 'EXT-X-BYTERANGE');
if (byterangeTag) {
[startByte, endByte] =
this.parseByteRange_(previousReference, byterangeTag.value);
} else if (partialSegmentRefs.length) {
startByte = partialSegmentRefs[0].startByte;
endByte = partialSegmentRefs[partialSegmentRefs.length - 1].endByte;
}
return new shaka.media.SegmentReference(
startTime,
endTime,
() => absoluteSegmentUri.length ? [absoluteSegmentUri] : [],
startByte,
endByte,
initSegmentReference,
timestampOffset,
/* appendWindowStart= */ 0,
/* appendWindowEnd= */ Infinity,
partialSegmentRefs,
);
}
/**
* Parse the startByte and endByte.
* @param {shaka.media.SegmentReference} previousReference
* @param {?string} byterange
* @return {!Array.<number>} An array with the start byte and end byte.
* @private
*/
parseByteRange_(previousReference, byterange) {
let startByte = 0;
let endByte = null;
// If BYTERANGE is not specified, the segment consists of the entire
// resource.
if (byterange) {
const blocks = byterange.split('@');
const byteLength = Number(blocks[0]);
if (blocks[1]) {
startByte = Number(blocks[1]);
} else {
goog.asserts.assert(previousReference,
'Cannot refer back to previous HLS segment!');
startByte = previousReference.endByte + 1;
}
endByte = startByte + byteLength - 1;
}
return [startByte, endByte];
}
/** @private */
notifySegments_() {
// The presentation timeline may or may not be set yet.
// If it does not yet exist, hold onto the segments until it does.
if (!this.presentationTimeline_) {
return;
}
for (const segments of this.segmentsToNotifyByStream_) {
this.presentationTimeline_.notifySegments(segments);
}
this.segmentsToNotifyByStream_ = [];
}
/**
* Parses shaka.hls.Segment objects into shaka.media.SegmentReferences.
*
* @param {string} verbatimMediaPlaylistUri
* @param {!shaka.hls.Playlist} playlist
* @param {string} type
* @param {string} mimeType
* @param {!Map.<number, number>} mediaSequenceToStartTime
* @param {!Map.<string, string>} variables
* @param {!Map.<number, number>} discontinuityToMediaSequence
* @return {!Promise<!Array.<!shaka.media.SegmentReference>>}
* @private
*/
async createSegments_(verbatimMediaPlaylistUri, playlist, type, mimeType,
mediaSequenceToStartTime, variables, discontinuityToMediaSequence) {
/** @type {Array.<!shaka.hls.Segment>} */
const hlsSegments = playlist.segments;
goog.asserts.assert(hlsSegments.length, 'Playlist should have segments!');
/** @type {shaka.media.InitSegmentReference} */
let initSegmentRef;
// We may need to look at the media itself to determine a segment start
// time.
const mediaSequenceNumber = shaka.hls.Utils.getFirstTagWithNameAsNumber(
playlist.tags, 'EXT-X-MEDIA-SEQUENCE', 0);
const skipTag = shaka.hls.Utils.getFirstTagWithName(playlist.tags,
'EXT-X-SKIP');
const skippedSegments =
skipTag ? Number(skipTag.getAttributeValue('SKIPPED-SEGMENTS')) : 0;
let position = mediaSequenceNumber + skippedSegments;
let firstStartTime;
// For live stream, use the cached value in the mediaSequenceToStartTime
// map if available.
// Since createSegments_() is asynchronous and we are updating the streams
// in parallel, the global playlistStartTime_ may get updated by other
// playlist updates rather than the current one.
if (this.isLive_() && mediaSequenceToStartTime.has(position)) {
firstStartTime = mediaSequenceToStartTime.get(position);
} else {
if (this.playlistStartTime_ == null) {
// For VOD and EVENT playlists, all variants must start at the same
// time, so we can fetch the start time once and reuse for the others.
// This is not guaranteed when updating a LIVE stream. We assume the
// first segment in each live playlist is no more than one segment out
// of sync with the other playlists, so we can fetch the start time for
// once.
initSegmentRef = this.getInitSegmentReference_(
playlist.absoluteUri, hlsSegments[0].tags, variables);
goog.asserts.assert(
type != shaka.util.ManifestParserUtils.ContentType.TEXT,
'Should only get start time from audio or video streams');
this.playlistStartTime_ = await this.getStartTime_(
verbatimMediaPlaylistUri, initSegmentRef, mimeType,
position, /* isDiscontinuity= */ false,
hlsSegments[0], variables);
}
firstStartTime = this.playlistStartTime_;
}
const firstSegmentUri = hlsSegments[0].absoluteUri;
shaka.log.debug('First segment', firstSegmentUri.split('/').pop(),
'starts at', firstStartTime);
let discontintuitySequenceNum = shaka.hls.Utils.getFirstTagWithNameAsNumber(
playlist.tags, 'EXT-X-DISCONTINUITY-SEQUENCE');
if (this.lowLatencyMode_) {
if (!discontinuityToMediaSequence.has(discontintuitySequenceNum)) {
discontinuityToMediaSequence.set(discontintuitySequenceNum, position);
}
if (skippedSegments) {
// With delta updates, the DISCONTINUITY may be skipped. Check if
// the discontintuity Sequence Number based on the media sequence
// number.
const disconMap = discontinuityToMediaSequence;
while (disconMap.has(discontintuitySequenceNum + 1) &&
disconMap.get(discontintuitySequenceNum + 1) < position) {
discontintuitySequenceNum++;
}
}
}
let timestampOffset =
this.discontinuityToTso_.get(discontintuitySequenceNum) || 0;
/** @type {!Array.<!shaka.media.SegmentReference>} */
const references = [];
for (let i = 0; i < hlsSegments.length; i++) {
const item = hlsSegments[i];
const previousReference = references[references.length - 1];
const startTime = (i == 0) ? firstStartTime :
previousReference.endTime;
position = mediaSequenceNumber + skippedSegments + i;
mediaSequenceToStartTime.set(position, startTime);
initSegmentRef = this.getInitSegmentReference_(playlist.absoluteUri,
item.tags, variables);
const discontintuityTag = shaka.hls.Utils.getFirstTagWithName(item.tags,
'EXT-X-DISCONTINUITY');
if (discontintuityTag) {
discontintuitySequenceNum++;
discontinuityToMediaSequence.set(discontintuitySequenceNum, position);
// eslint-disable-next-line no-await-in-loop
timestampOffset = await this.getTimestampOffset_(
discontintuitySequenceNum, verbatimMediaPlaylistUri, initSegmentRef,
mimeType, position, item, variables, startTime);
}
// If the stream is low latency and the user has not configured the
// lowLatencyMode, but if it has been configured to activate the
// lowLatencyMode if a stream of this type is detected, we automatically
// activate the lowLatencyMode.
if (!this.lowLatencyMode_) {
const autoLowLatencyMode = this.playerInterface_.isAutoLowLatencyMode();
if (autoLowLatencyMode) {
this.playerInterface_.enableLowLatencyMode();
this.lowLatencyMode_ = this.playerInterface_.isLowLatencyMode();
}
}
const extinfTag =
shaka.hls.Utils.getFirstTagWithName(item.tags, 'EXTINF');
if (this.lowLatencyMode_ || extinfTag) {
const reference = this.createSegmentReference_(
initSegmentRef,
previousReference,
item,
startTime,
timestampOffset,
variables,
playlist.absoluteUri);
references.push(reference);
} else if (!this.lowLatencyMode_) {
// If a segment has no extinfTag, it must contain partial segments.
shaka.log.alwaysWarn('Low-latency HLS live stream detected, but ' +
'low-latency streaming mode is not enabled in Shaka Player. ' +
'Set streaming.lowLatencyMode configuration to true, and see ' +
'https://bit.ly/3clctcj for details.');
}
}
return references;
}
/**
* Gets the start time of the first segment of the playlist from existing
* value (if possible) or by downloading it and parsing it otherwise.
*
* @param {number} discontintuitySequenceNum
* @param {string} verbatimMediaPlaylistUri
* @param {shaka.media.InitSegmentReference} initSegmentRef
* @param {string} mimeType
* @param {number} mediaSequenceNumber
* @param {!shaka.hls.Segment} segment
* @param {!Map.<string, string>} variables
* @param {number} startTime
* @return {!Promise.<number>}
* @throws {shaka.util.Error}
* @private
*/
async getTimestampOffset_(discontintuitySequenceNum,
verbatimMediaPlaylistUri, initSegmentRef,
mimeType, mediaSequenceNumber, segment, variables, startTime) {
let timestampOffset = 0;
if (this.discontinuityToTso_.has(discontintuitySequenceNum)) {
timestampOffset =
this.discontinuityToTso_.get(discontintuitySequenceNum);
} else {
const mediaStartTime = await this.getStartTime_(
verbatimMediaPlaylistUri, initSegmentRef, mimeType,
mediaSequenceNumber, /* isDiscontinuity= */ true, segment,
variables);
timestampOffset = startTime - mediaStartTime;
shaka.log.v1('Segment timestampOffset =', timestampOffset);
this.discontinuityToTso_.set(
discontintuitySequenceNum, timestampOffset);
}
return timestampOffset;
}
/**
* Try to fetch the starting part of a segment, and fall back to a full
* segment if we have to.
*
* @param {!shaka.media.AnySegmentReference} reference
* @return {!Promise.<shaka.extern.Response>}
* @private
*/
async fetchStartOfSegment_(reference) {
const requestType = shaka.net.NetworkingEngine.RequestType.SEGMENT;
// Create two requests:
// 1. A partial request meant to fetch the smallest part of the segment
// required to get the time stamp.
// 2. A full request meant as a fallback for when the server does not
// support partial requests.
const fullRequest = shaka.util.Networking.createSegmentRequest(
reference.getUris(),
reference.startByte,
reference.endByte,
this.config_.retryParameters);
if (this.config_.hls.useFullSegmentsForStartTime) {
return this.makeNetworkRequest_(fullRequest, requestType);
}
const partialRequest = shaka.util.Networking.createSegmentRequest(
reference.getUris(),
reference.startByte,
reference.startByte + shaka.hls.HlsParser.START_OF_SEGMENT_SIZE_ - 1,
this.config_.retryParameters);
// TODO(vaage): The need to do fall back requests is not likely to be unique
// to here. It would be nice if the fallback(s) could be included into
// the same abortable operation as the original request.
//
// What would need to change with networking engine to support requests
// with fallback(s)?
try {
const response = await this.makeNetworkRequest_(
partialRequest, requestType);
return response;
} catch (e) {
// If the networking operation was aborted, we don't want to treat it as
// a request failure. We surface the error so that the OPERATION_ABORTED
// error will be handled correctly.
if (e.code == shaka.util.Error.Code.OPERATION_ABORTED) {
throw e;
}
// The partial request may fail for a number of reasons.
// Some servers do not support Range requests, and others do not support
// the OPTIONS request which must be made before any cross-origin Range
// request. Since this fallback is expensive, warn the app developer.
shaka.log.alwaysWarn('Unable to fetch the starting part of HLS ' +
'segment! Falling back to a full segment request, ' +
'which is expensive! Your server should ' +
'support Range requests and CORS preflights.',
partialRequest.uris[0]);
const response = await this.makeNetworkRequest_(fullRequest, requestType);
return response;
}
}
/**
* Gets the start time of a segment from the existing manifest (if possible)
* or by downloading it and parsing it otherwise.
*
* @param {string} verbatimMediaPlaylistUri
* @param {shaka.media.InitSegmentReference} initSegmentRef
* @param {string} mimeType
* @param {number} mediaSequenceNumber
* @param {boolean} isDiscontinuity
* @param {!shaka.hls.Segment} segment
* @param {!Map.<string, string>} variables
* @return {!Promise.<number>}
* @private
*/
async getStartTime_(
verbatimMediaPlaylistUri, initSegmentRef, mimeType, mediaSequenceNumber,
isDiscontinuity, segment, variables) {
const segmentRef = this.createSegmentReference_(
initSegmentRef,
/* previousReference= */ null,
segment,
/* startTime= */ 0,
/* timestampOffset= */ 0,
variables,
/* absoluteMediaPlaylistUri= */ '');
// If we are updating the manifest, we can usually skip fetching the segment
// by examining the references we already have. This won't be possible if
// there was some kind of lag or delay updating the manifest on the server,
// in which extreme case we would fall back to fetching a segment. This
// allows us to both avoid fetching segments when possible, and recover from
// certain server-side issues gracefully.
// Do not use cached start time for the segments with discontinuity tags.
if (this.manifest_ && !isDiscontinuity) {
const streamInfo =
this.uriToStreamInfosMap_.get(verbatimMediaPlaylistUri);
const startTime = streamInfo.mediaSequenceToStartTime.get(
mediaSequenceNumber);
if (startTime != undefined) {
// We found it! Avoid fetching and parsing the segment.
shaka.log.v1('Found segment start time in previous manifest',
startTime);
return startTime;
}
shaka.log.debug(
'Unable to find segment start time in previous manifest!');
}
// TODO: Introduce a new tag to extend HLS and provide the first segment's
// start time. This will avoid the need for these fetches in content
// packaged with Shaka Packager. This web-friendly extension to HLS can
// then be proposed to Apple for inclusion in a future version of HLS.
// See https://github.com/google/shaka-packager/issues/294
shaka.log.v1('Fetching segment to find start time');
mimeType = mimeType.toLowerCase();
if (shaka.hls.HlsParser.RAW_FORMATS_.includes(mimeType)) {
// Raw formats contain no timestamps. Even if there is an ID3 tag with a
// timestamp, that's not going to be honored by MediaSource, which will
// use sequence mode for these segments. We don't yet support sequence
// mode, so we must reject these streams.
// TODO(#2337): Support sequence mode and align raw format timestamps to
// other streams.
shaka.log.alwaysWarn(
'Raw formats are not yet supported. Skipping ' + mimeType);
throw new shaka.util.Error(
shaka.util.Error.Severity.RECOVERABLE,
shaka.util.Error.Category.MANIFEST,
shaka.util.Error.Code.HLS_INTERNAL_SKIP_STREAM);
}
if (mimeType == 'video/webm') {
shaka.log.alwaysWarn('WebM in HLS is not yet supported. Skipping.');
throw new shaka.util.Error(
shaka.util.Error.Severity.RECOVERABLE,
shaka.util.Error.Category.MANIFEST,
shaka.util.Error.Code.HLS_INTERNAL_SKIP_STREAM);
}
if (mimeType == 'video/mp4' || mimeType == 'audio/mp4') {
// We also need the init segment to get the correct timescale. But if the
// stream is self-initializing, use the same response for both.
const fetches = [this.fetchStartOfSegment_(segmentRef)];
if (initSegmentRef) {
fetches.push(this.fetchStartOfSegment_(initSegmentRef));
}
const responses = await Promise.all(fetches);
// If the stream is self-initializing, use the main segment in-place of
// the init segment.
const segmentResponse = responses[0];
const initSegmentResponse = responses[1] || responses[0];
return this.getStartTimeFromMp4Segment_(
verbatimMediaPlaylistUri, segmentResponse.uri,
segmentResponse.data, initSegmentResponse.data);
}
if (mimeType == 'video/mp2t') {
const response = await this.fetchStartOfSegment_(segmentRef);
goog.asserts.assert(response.data, 'Should have a response body!');
return this.getStartTimeFromTsSegment_(
verbatimMediaPlaylistUri, response.uri, response.data);
}
throw new shaka.util.Error(
shaka.util.Error.Severity.CRITICAL,
shaka.util.Error.Category.MANIFEST,
shaka.util.Error.Code.HLS_COULD_NOT_PARSE_SEGMENT_START_TIME,
verbatimMediaPlaylistUri);
}
/**
* Parses an mp4 segment to get its start time.
*
* @param {string} playlistUri
* @param {string} segmentUri
* @param {BufferSource} mediaData
* @param {BufferSource} initData
* @return {number}
* @private
*/
getStartTimeFromMp4Segment_(playlistUri, segmentUri, mediaData, initData) {
const Mp4Parser = shaka.util.Mp4Parser;
let timescale = 0;
new Mp4Parser()
.box('moov', Mp4Parser.children)
.box('trak', Mp4Parser.children)
.box('mdia', Mp4Parser.children)
.fullBox('mdhd', (box) => {
goog.asserts.assert(
box.version == 0 || box.version == 1,
'MDHD version can only be 0 or 1');
const parsedMDHDBox = shaka.util.Mp4BoxParsers.parseMDHD(
box.reader, box.version);
timescale = parsedMDHDBox.timescale;
box.parser.stop();
}).parse(initData, /* partialOkay= */ true);
if (!timescale) {
shaka.log.error('Unable to find timescale in init segment!');
throw new shaka.util.Error(
shaka.util.Error.Severity.CRITICAL,
shaka.util.Error.Category.MANIFEST,
shaka.util.Error.Code.HLS_COULD_NOT_PARSE_SEGMENT_START_TIME,
playlistUri, segmentUri);
}
let startTime = 0;
let parsedMedia = false;
new Mp4Parser()
.box('moof', Mp4Parser.children)
.box('traf', Mp4Parser.children)
.fullBox('tfdt', (box) => {
goog.asserts.assert(
box.version == 0 || box.version == 1,
'TFDT version can only be 0 or 1');
const parsedTFDTBox = shaka.util.Mp4BoxParsers.parseTFDT(
box.reader, box.version);
const baseTime = parsedTFDTBox.baseMediaDecodeTime;
startTime = baseTime / timescale;
parsedMedia = true;
box.parser.stop();
}).parse(mediaData, /* partialOkay= */ true);
if (!parsedMedia) {
throw new shaka.util.Error(
shaka.util.Error.Severity.CRITICAL,
shaka.util.Error.Category.MANIFEST,
shaka.util.Error.Code.HLS_COULD_NOT_PARSE_SEGMENT_START_TIME,
playlistUri, segmentUri);
}
return startTime;
}
/**
* Parses a TS segment to get its start time.
*
* @param {string} playlistUri
* @param {string} segmentUri
* @param {BufferSource} data
* @return {number}
* @private
*/
getStartTimeFromTsSegment_(playlistUri, segmentUri, data) {
const reader = new shaka.util.DataViewReader(
data, shaka.util.DataViewReader.Endianness.BIG_ENDIAN);
const fail = () => {
throw new shaka.util.Error(
shaka.util.Error.Severity.CRITICAL,
shaka.util.Error.Category.MANIFEST,
shaka.util.Error.Code.HLS_COULD_NOT_PARSE_SEGMENT_START_TIME,
playlistUri, segmentUri);
};
let packetStart = 0;
let syncByte = 0;
const skipPacket = () => {
// 188-byte packets are standard, so assume that.
reader.seek(packetStart + 188);
syncByte = reader.readUint8();
if (syncByte != 0x47) {
// We haven't found the sync byte, so try it as a 192-byte packet.
reader.seek(packetStart + 192);
syncByte = reader.readUint8();
}
if (syncByte != 0x47) {
// We still haven't found the sync byte, so try as a 204-byte packet.
reader.seek(packetStart + 204);
syncByte = reader.readUint8();
}
if (syncByte != 0x47) {
// We still haven't found the sync byte, so the packet was of a
// non-standard size.
fail();
}
// Put the sync byte back so we can read it in the next loop.
reader.rewind(1);
};
// We will look a few packet-lengths forward to find the first sync byte.
// Note that we are using this method on what is already a subset of the
// file (the first |shaka.hls.HlsParser.START_OF_SEGMENT_SIZE_| bytes), so
// we can't look too far ahead to begin with.
let syncByteScanLength = Math.min(reader.getLength() - 188, 5 * 188);
// TODO: refactor this while loop for better readability.
// eslint-disable-next-line no-constant-condition
while (true) {
// Format reference: https://bit.ly/TsPacket
packetStart = reader.getPosition();
syncByte = reader.readUint8();
if (syncByte != 0x47) {
if (syncByteScanLength > 0) {
// This file could have started with a cut-off TS packet. Scan forward
// until we find a sync byte.
syncByteScanLength -= 1;
continue;
}
fail();
}
// If we've found a sync byte, stop scanning forward for future packets.
syncByteScanLength = 0;
const flagsAndPacketId = reader.readUint16();
const packetId = flagsAndPacketId & 0x1fff;
if (packetId == 0x1fff) {
// A "null" TS packet. Skip this TS packet and try again.
skipPacket();
continue;
}
const hasPesPacket = flagsAndPacketId & 0x4000;
if (!hasPesPacket) {
// Not a PES packet yet. Skip this TS packet and try again.
skipPacket();
continue;
}
const flags = reader.readUint8();
const adaptationFieldControl = (flags & 0x30) >> 4;
if (adaptationFieldControl == 0 /* reserved */ ||
adaptationFieldControl == 2 /* adaptation field, no payload */) {
fail();
}
if (adaptationFieldControl == 3) {
// Skip over adaptation field.
const length = reader.readUint8();
reader.skip(length);
}
// Now we come to the PES header (hopefully).
// Format reference: https://bit.ly/TsPES
const startCode = reader.readUint32();
const startCodePrefix = startCode >> 8;
if (startCodePrefix != 1) {
// Not a PES packet yet. Skip this TS packet and try again.
skipPacket();
continue;
}
// Skip the 16-bit PES length and the first 8 bits of the optional header.
reader.skip(3);
// The next 8 bits contain flags about DTS & PTS.
const ptsDtsIndicator = reader.readUint8() >> 6;
if (ptsDtsIndicator == 0 /* no timestamp */ ||
ptsDtsIndicator == 1 /* forbidden */) {
fail();
}
const pesHeaderLengthRemaining = reader.readUint8();
if (pesHeaderLengthRemaining == 0) {
fail();
}
if (ptsDtsIndicator == 2 /* PTS only */) {
goog.asserts.assert(pesHeaderLengthRemaining == 5, 'Bad PES header?');
} else if (ptsDtsIndicator == 3 /* PTS and DTS */) {
goog.asserts.assert(pesHeaderLengthRemaining == 10, 'Bad PES header?');
}
const pts0 = reader.readUint8();
const pts1 = reader.readUint16();
const pts2 = reader.readUint16();
// Reconstruct 33-bit PTS from the 5-byte, padded structure.
const ptsHigh3 = (pts0 & 0x0e) >> 1;
const ptsLow30 = ((pts1 & 0xfffe) << 14) | ((pts2 & 0xfffe) >> 1);
// Reconstruct the PTS as a float. Avoid bitwise operations to combine
// because bitwise ops treat the values as 32-bit ints.
const pts = ptsHigh3 * (1 << 30) + ptsLow30;
return pts / shaka.hls.HlsParser.TS_TIMESCALE_;
}
}
/**
* Replaces the variables of a given URI.
*
* @param {string} uri
* @param {!Map.<string, string>} variables
* @return {string}
* @private
*/
variableSubstitution_(uri, variables) {
let newUri = String(uri).replace(/%7B/g, '{').replace(/%7D/g, '}');
const uriVariables = newUri.match(/{\$\w*}/g);
if (uriVariables) {
for (const variable of uriVariables) {
// Note: All variables have the structure {$...}
const variableName = variable.slice(2, variable.length - 1);
const replaceValue = variables.get(variableName);
if (replaceValue) {
newUri = newUri.replace(variable, replaceValue);
} else {
shaka.log.error('A variable has been found that is not declared',
variableName);
throw new shaka.util.Error(
shaka.util.Error.Severity.CRITICAL,
shaka.util.Error.Category.MANIFEST,
shaka.util.Error.Code.HLS_VARIABLE_NOT_FOUND,
variableName);
}
}
}
return newUri;
}
/**
* Attempts to guess stream's mime type based on content type and URI.
*
* @param {string} contentType
* @param {string} codecs
* @param {!shaka.hls.Playlist} playlist
* @param {!Map.<string, string>} variables
* @return {!Promise.<string>}
* @private
*/
async guessMimeType_(contentType, codecs, playlist, variables) {
const HlsParser = shaka.hls.HlsParser;
const ContentType = shaka.util.ManifestParserUtils.ContentType;
const requestType = shaka.net.NetworkingEngine.RequestType.SEGMENT;
goog.asserts.assert(playlist.segments.length,
'Playlist should have segments!');
const firstSegmentUri = this.variableSubstitution_(
playlist.segments[0].absoluteUri, variables);
const parsedUri = new goog.Uri(firstSegmentUri);
const extension = parsedUri.getPath().split('.').pop();
const map = HlsParser.EXTENSION_MAP_BY_CONTENT_TYPE_[contentType];
const mimeType = map[extension];
if (mimeType) {
return mimeType;
}
if (contentType == ContentType.TEXT) {
// The extension map didn't work.
if (!codecs || codecs == 'vtt' || codecs == 'wvtt') {
// If codecs is 'vtt', it's WebVTT.
// If there was no codecs string, assume HLS text streams are WebVTT.
return 'text/vtt';
} else {
// Otherwise, assume MP4-embedded text, since text-based formats tend
// not to have a codecs string at all.
return 'application/mp4';
}
}
// If unable to guess mime type, request a segment and try getting it
// from the response.
const headRequest = shaka.net.NetworkingEngine.makeRequest(
[firstSegmentUri], this.config_.retryParameters);
headRequest.method = 'HEAD';
const response = await this.makeNetworkRequest_(
headRequest, requestType);
const contentMimeType = response.headers['content-type'];
if (!contentMimeType) {
// If the HLS content is lacking in both MIME type metadata and
// segment file extensions, we fall back to assuming it's MP4.
const fallbackMimeType = map['mp4'];
return fallbackMimeType;
}
// Split the MIME type in case the server sent additional parameters.
return contentMimeType.split(';')[0];
}
/**
* Returns a tag with a given name.
* Throws an error if tag was not found.
*
* @param {!Array.<shaka.hls.Tag>} tags
* @param {string} tagName
* @return {!shaka.hls.Tag}
* @private
*/
getRequiredTag_(tags, tagName) {
const tag = shaka.hls.Utils.getFirstTagWithName(tags, tagName);
if (!tag) {
throw new shaka.util.Error(
shaka.util.Error.Severity.CRITICAL,
shaka.util.Error.Category.MANIFEST,
shaka.util.Error.Code.HLS_REQUIRED_TAG_MISSING, tagName);
}
return tag;
}
/**
* @param {shaka.extern.Stream} stream
* @param {?string} width
* @param {?string} height
* @param {?string} frameRate
* @param {?string} videoRange
* @private
*/
addVideoAttributes_(stream, width, height, frameRate, videoRange) {
if (stream) {
stream.width = Number(width) || undefined;
stream.height = Number(height) || undefined;
stream.frameRate = Number(frameRate) || undefined;
stream.hdr = videoRange || undefined;
}
}
/**
* Makes a network request for the manifest and returns a Promise
* with the resulting data.
*
* @param {string} absoluteUri
* @return {!Promise.<!shaka.extern.Response>}
* @private
*/
requestManifest_(absoluteUri) {
const requestType = shaka.net.NetworkingEngine.RequestType.MANIFEST;
const request = shaka.net.NetworkingEngine.makeRequest(
[absoluteUri], this.config_.retryParameters);
return this.makeNetworkRequest_(request, requestType);
}
/**
* Called when the update timer ticks. Because parsing a manifest is async,
* this method is async. To work with this, this method will schedule the next
* update when it finished instead of using a repeating-start.
*
* @return {!Promise}
* @private
*/
async onUpdate_() {
shaka.log.info('Updating manifest...');
goog.asserts.assert(
this.updatePlaylistDelay_ > 0,
'We should only call |onUpdate_| when we are suppose to be updating.');
// Detect a call to stop()
if (!this.playerInterface_) {
return;
}
try {
await this.update();
const delay = this.updatePlaylistDelay_;
this.updatePlaylistTimer_.tickAfter(/* seconds= */ delay);
} catch (error) {
// Detect a call to stop() during this.update()
if (!this.playerInterface_) {
return;
}
goog.asserts.assert(error instanceof shaka.util.Error,
'Should only receive a Shaka error');
// We will retry updating, so override the severity of the error.
error.severity = shaka.util.Error.Severity.RECOVERABLE;
this.playerInterface_.onError(error);
// Try again very soon.
this.updatePlaylistTimer_.tickAfter(/* seconds= */ 0.1);
}
}
/**
* @return {boolean}
* @private
*/
isLive_() {
const PresentationType = shaka.hls.HlsParser.PresentationType_;
return this.presentationType_ != PresentationType.VOD;
}
/**
* @param {shaka.hls.HlsParser.PresentationType_} type
* @private
*/
setPresentationType_(type) {
this.presentationType_ = type;
if (this.presentationTimeline_) {
this.presentationTimeline_.setStatic(!this.isLive_());
}
// If this manifest is not for live content, then we have no reason to
// update it.
if (!this.isLive_()) {
this.updatePlaylistTimer_.stop();
}
}
/**
* Create a networking request. This will manage the request using the
* parser's operation manager. If the parser has already been stopped, the
* request will not be made.
*
* @param {shaka.extern.Request} request
* @param {shaka.net.NetworkingEngine.RequestType} type
* @return {!Promise.<shaka.extern.Response>}
* @private
*/
makeNetworkRequest_(request, type) {
if (!this.operationManager_) {
throw new shaka.util.Error(
shaka.util.Error.Severity.CRITICAL,
shaka.util.Error.Category.PLAYER,
shaka.util.Error.Code.OPERATION_ABORTED);
}
const op = this.playerInterface_.networkingEngine.request(type, request);
this.operationManager_.manage(op);
return op.promise;
}
/**
* @param {!shaka.hls.Tag} drmTag
* @return {?shaka.extern.DrmInfo}
* @private
*/
static widevineDrmParser_(drmTag) {
const method = drmTag.getRequiredAttrValue('METHOD');
const VALID_METHODS = ['SAMPLE-AES', 'SAMPLE-AES-CTR'];
if (!VALID_METHODS.includes(method)) {
shaka.log.error('Widevine in HLS is only supported with [',
VALID_METHODS.join(', '), '], not', method);
return null;
}
const uri = drmTag.getRequiredAttrValue('URI');
const parsedData = shaka.net.DataUriPlugin.parseRaw(uri);
// The data encoded in the URI is a PSSH box to be used as init data.
const pssh = shaka.util.BufferUtils.toUint8(parsedData.data);
const drmInfo = shaka.util.ManifestParserUtils.createDrmInfo(
'com.widevine.alpha', [
{initDataType: 'cenc', initData: pssh},
]);
const keyId = drmTag.getAttributeValue('KEYID');
if (keyId) {
const keyIdLowerCase = keyId.toLowerCase();
// This value should begin with '0x':
goog.asserts.assert(
keyIdLowerCase.startsWith('0x'), 'Incorrect KEYID format!');
// But the output should not contain the '0x':
drmInfo.keyIds = new Set([keyIdLowerCase.substr(2)]);
}
return drmInfo;
}
/**
* See: https://docs.microsoft.com/en-us/playready/packaging/mp4-based-formats-supported-by-playready-clients?tabs=case4
*
* @param {!shaka.hls.Tag} drmTag
* @return {?shaka.extern.DrmInfo}
* @private
*/
static playreadyDrmParser_(drmTag) {
const method = drmTag.getRequiredAttrValue('METHOD');
const VALID_METHODS = ['SAMPLE-AES', 'SAMPLE-AES-CTR'];
if (!VALID_METHODS.includes(method)) {
shaka.log.error('PlayReady in HLS is only supported with [',
VALID_METHODS.join(', '), '], not', method);
return null;
}
const uri = drmTag.getRequiredAttrValue('URI');
const parsedData = shaka.net.DataUriPlugin.parseRaw(uri);
// The data encoded in the URI is a PlayReady Pro Object, so we need
// convert it to pssh.
const data = shaka.util.BufferUtils.toUint8(parsedData.data);
const systemId = new Uint8Array([
0x9a, 0x04, 0xf0, 0x79, 0x98, 0x40, 0x42, 0x86,
0xab, 0x92, 0xe6, 0x5b, 0xe0, 0x88, 0x5f, 0x95,
]);
const pssh = shaka.util.Pssh.createPssh(data, systemId);
const drmInfo = shaka.util.ManifestParserUtils.createDrmInfo(
'com.microsoft.playready', [
{initDataType: 'cenc', initData: pssh},
]);
return drmInfo;
}
};
/**
* @typedef {{
* stream: !shaka.extern.Stream,
* verbatimMediaPlaylistUri: string,
* absoluteMediaPlaylistUri: string,
* minTimestamp: number,
* maxTimestamp: number,
* mediaSequenceToStartTime: !Map.<number, number>,
* discontinuityToMediaSequence: !Map.<number, number>,
* canSkipSegments: boolean
* }}
*
* @description
* Contains a stream and information about it.
*
* @property {!shaka.extern.Stream} stream
* The Stream itself.
* @property {string} verbatimMediaPlaylistUri
* The verbatim media playlist URI, as it appeared in the master playlist.
* This has not been canonicalized into an absolute URI. This gives us a
* consistent key for this playlist, even if redirects cause us to update
* from different origins each time.
* @property {string} absoluteMediaPlaylistUri
* The absolute media playlist URI, resolved relative to the master playlist
* and updated to reflect any redirects.
* @property {number} minTimestamp
* The minimum timestamp found in the stream.
* @property {number} maxTimestamp
* The maximum timestamp found in the stream.
* @property {!Map.<number, number>} mediaSequenceToStartTime
* A map of media sequence numbers to media start times.
* @property {!Map.<number, number>} discontinuityToMediaSequence
* A map of discontinuity sequence numbers to the media sequence number of the
* segment starting with that discontinuity sequence number.
* @property {boolean} canSkipSegments
* True if the server supports delta playlist updates, and we can send a
* request for a playlist that can skip older media segments.
*/
shaka.hls.HlsParser.StreamInfo;
/**
* @typedef {{
* audio: !Array.<shaka.hls.HlsParser.StreamInfo>,
* video: !Array.<shaka.hls.HlsParser.StreamInfo>
* }}
*
* @description Audio and video stream infos.
* @property {!Array.<shaka.hls.HlsParser.StreamInfo>} audio
* @property {!Array.<shaka.hls.HlsParser.StreamInfo>} video
*/
shaka.hls.HlsParser.StreamInfos;
/**
* @const {!Object.<string, string>}
* @private
*/
shaka.hls.HlsParser.AUDIO_EXTENSIONS_TO_MIME_TYPES_ = {
'mp4': 'audio/mp4',
'mp4a': 'audio/mp4',
'm4s': 'audio/mp4',
'm4i': 'audio/mp4',
'm4a': 'audio/mp4',
'm4f': 'audio/mp4',
'cmfa': 'audio/mp4',
// MPEG2-TS also uses video/ for audio: https://bit.ly/TsMse
'ts': 'video/mp2t',
// Raw formats:
'aac': 'audio/aac',
'ac3': 'audio/ac3',
'ec3': 'audio/ec3',
'mp3': 'audio/mpeg',
};
/**
* MIME types of raw formats.
* TODO(#2337): Support raw formats and share this list among parsers.
*
* @const {!Array.<string>}
* @private
*/
shaka.hls.HlsParser.RAW_FORMATS_ = [
'audio/aac',
'audio/ac3',
'audio/ec3',
'audio/mpeg',
];
/**
* @const {!Object.<string, string>}
* @private
*/
shaka.hls.HlsParser.VIDEO_EXTENSIONS_TO_MIME_TYPES_ = {
'mp4': 'video/mp4',
'mp4v': 'video/mp4',
'm4s': 'video/mp4',
'm4i': 'video/mp4',
'm4v': 'video/mp4',
'm4f': 'video/mp4',
'cmfv': 'video/mp4',
'ts': 'video/mp2t',
};
/**
* @const {!Object.<string, string>}
* @private
*/
shaka.hls.HlsParser.TEXT_EXTENSIONS_TO_MIME_TYPES_ = {
'mp4': 'application/mp4',
'm4s': 'application/mp4',
'm4i': 'application/mp4',
'm4f': 'application/mp4',
'cmft': 'application/mp4',
'vtt': 'text/vtt',
'ttml': 'application/ttml+xml',
};
/**
* @const {!Object.<string, !Object.<string, string>>}
* @private
*/
shaka.hls.HlsParser.EXTENSION_MAP_BY_CONTENT_TYPE_ = {
'audio': shaka.hls.HlsParser.AUDIO_EXTENSIONS_TO_MIME_TYPES_,
'video': shaka.hls.HlsParser.VIDEO_EXTENSIONS_TO_MIME_TYPES_,
'text': shaka.hls.HlsParser.TEXT_EXTENSIONS_TO_MIME_TYPES_,
};
/**
* @typedef {function(!shaka.hls.Tag):?shaka.extern.DrmInfo}
* @private
*/
shaka.hls.HlsParser.DrmParser_;
/**
* @const {!Object.<string, shaka.hls.HlsParser.DrmParser_>}
* @private
*/
shaka.hls.HlsParser.KEYFORMATS_TO_DRM_PARSERS_ = {
/* TODO: https://github.com/google/shaka-player/issues/382
'com.apple.streamingkeydelivery':
shaka.hls.HlsParser.fairplayDrmParser_,
*/
'urn:uuid:edef8ba9-79d6-4ace-a3c8-27dcd51d21ed':
shaka.hls.HlsParser.widevineDrmParser_,
'com.microsoft.playready':
shaka.hls.HlsParser.playreadyDrmParser_,
};
/**
* @enum {string}
* @private
*/
shaka.hls.HlsParser.PresentationType_ = {
VOD: 'VOD',
EVENT: 'EVENT',
LIVE: 'LIVE',
};
/**
* @const {number}
* @private
*/
shaka.hls.HlsParser.TS_TIMESCALE_ = 90000;
/**
* The amount of data from the start of a segment we will try to fetch when we
* need to know the segment start time. This allows us to avoid fetching the
* entire segment in many cases.
*
* @const {number}
* @private
*/
shaka.hls.HlsParser.START_OF_SEGMENT_SIZE_ = 2048;
shaka.media.ManifestParser.registerParserByExtension(
'm3u8', () => new shaka.hls.HlsParser());
shaka.media.ManifestParser.registerParserByMime(
'application/x-mpegurl', () => new shaka.hls.HlsParser());
shaka.media.ManifestParser.registerParserByMime(
'application/vnd.apple.mpegurl', () => new shaka.hls.HlsParser());