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dash_parser.js
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dash_parser.js
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/*! @license
* Shaka Player
* Copyright 2016 Google LLC
* SPDX-License-Identifier: Apache-2.0
*/
goog.provide('shaka.dash.DashParser');
goog.require('goog.asserts');
goog.require('shaka.abr.Ewma');
goog.require('shaka.dash.ContentProtection');
goog.require('shaka.dash.MpdUtils');
goog.require('shaka.dash.SegmentBase');
goog.require('shaka.dash.SegmentList');
goog.require('shaka.dash.SegmentTemplate');
goog.require('shaka.log');
goog.require('shaka.media.ManifestParser');
goog.require('shaka.media.PresentationTimeline');
goog.require('shaka.media.SegmentIndex');
goog.require('shaka.net.NetworkingEngine');
goog.require('shaka.text.TextEngine');
goog.require('shaka.util.Error');
goog.require('shaka.util.Functional');
goog.require('shaka.util.Iterables');
goog.require('shaka.util.LanguageUtils');
goog.require('shaka.util.ManifestParserUtils');
goog.require('shaka.util.MimeUtils');
goog.require('shaka.util.Networking');
goog.require('shaka.util.OperationManager');
goog.require('shaka.util.PeriodCombiner');
goog.require('shaka.util.StringUtils');
goog.require('shaka.util.Timer');
goog.require('shaka.util.XmlUtils');
/**
* Creates a new DASH parser.
*
* @implements {shaka.extern.ManifestParser}
* @export
*/
shaka.dash.DashParser = class {
/** Creates a new DASH parser. */
constructor() {
/** @private {?shaka.extern.ManifestConfiguration} */
this.config_ = null;
/** @private {?shaka.extern.ManifestParser.PlayerInterface} */
this.playerInterface_ = null;
/** @private {!Array.<string>} */
this.manifestUris_ = [];
/** @private {?shaka.extern.Manifest} */
this.manifest_ = null;
/** @private {number} */
this.globalId_ = 1;
/**
* A map of IDs to SegmentIndex objects.
* ID: Period@id,AdaptationSet@id,@Representation@id
* e.g.: '1,5,23'
* @private {!Object.<string, !shaka.media.SegmentIndex>}
*/
this.segmentIndexMap_ = {};
/**
* A map of period ids to their durations
* @private {!Object.<string, number>}
*/
this.periodDurations_ = {};
/** @private {shaka.util.PeriodCombiner} */
this.periodCombiner_ = new shaka.util.PeriodCombiner();
/**
* The update period in seconds, or 0 for no updates.
* @private {number}
*/
this.updatePeriod_ = 0;
/**
* An ewma that tracks how long updates take.
* This is to mitigate issues caused by slow parsing on embedded devices.
* @private {!shaka.abr.Ewma}
*/
this.averageUpdateDuration_ = new shaka.abr.Ewma(5);
/** @private {shaka.util.Timer} */
this.updateTimer_ = new shaka.util.Timer(() => {
this.onUpdate_();
});
/** @private {!shaka.util.OperationManager} */
this.operationManager_ = new shaka.util.OperationManager();
/**
* Largest period start time seen.
* @private {?number}
*/
this.largestPeriodStartTime_ = null;
/**
* The minimum of the availabilityTimeOffset values among the adaptation
* sets.
* @private {number}
*/
this.minTotalAvailabilityTimeOffset_ = Infinity;
/** @private {boolean} */
this.lowLatencyMode_ = false;
}
/**
* @override
* @exportInterface
*/
configure(config) {
goog.asserts.assert(config.dash != null,
'DashManifestConfiguration should not be null!');
this.config_ = config;
}
/**
* @override
* @exportInterface
*/
async start(uri, playerInterface) {
goog.asserts.assert(this.config_, 'Must call configure() before start()!');
this.lowLatencyMode_ = playerInterface.isLowLatencyMode();
this.manifestUris_ = [uri];
this.playerInterface_ = playerInterface;
const updateDelay = await this.requestManifest_();
if (this.playerInterface_) {
this.setUpdateTimer_(updateDelay);
}
// 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);
}
goog.asserts.assert(this.manifest_, 'Manifest should be non-null!');
return this.manifest_;
}
/**
* @override
* @exportInterface
*/
stop() {
// When the parser stops, release all segment indexes, which stops their
// timers, as well.
for (const segmentIndex of Object.values(this.segmentIndexMap_)) {
segmentIndex.release();
}
if (this.periodCombiner_) {
this.periodCombiner_.release();
}
this.playerInterface_ = null;
this.config_ = null;
this.manifestUris_ = [];
this.manifest_ = null;
this.segmentIndexMap_ = {};
this.periodCombiner_ = null;
if (this.updateTimer_ != null) {
this.updateTimer_.stop();
this.updateTimer_ = null;
}
return this.operationManager_.destroy();
}
/**
* @override
* @exportInterface
*/
async update() {
try {
await this.requestManifest_();
} catch (error) {
if (!this.playerInterface_ || !error) {
return;
}
goog.asserts.assert(error instanceof shaka.util.Error, 'Bad error type');
this.playerInterface_.onError(error);
}
}
/**
* @override
* @exportInterface
*/
onExpirationUpdated(sessionId, expiration) {
// No-op
}
/**
* Makes a network request for the manifest and parses the resulting data.
*
* @return {!Promise.<number>} Resolves with the time it took, in seconds, to
* fulfill the request and parse the data.
* @private
*/
async requestManifest_() {
const requestType = shaka.net.NetworkingEngine.RequestType.MANIFEST;
const request = shaka.net.NetworkingEngine.makeRequest(
this.manifestUris_, this.config_.retryParameters);
const networkingEngine = this.playerInterface_.networkingEngine;
const startTime = Date.now();
const operation = networkingEngine.request(requestType, request);
this.operationManager_.manage(operation);
const response = await operation.promise;
// Detect calls to stop().
if (!this.playerInterface_) {
return 0;
}
// For redirections add the response uri to the first entry in the
// Manifest Uris array.
if (response.uri && !this.manifestUris_.includes(response.uri)) {
this.manifestUris_.unshift(response.uri);
}
// This may throw, but it will result in a failed promise.
await this.parseManifest_(response.data, response.uri);
// Keep track of how long the longest manifest update took.
const endTime = Date.now();
const updateDuration = (endTime - startTime) / 1000.0;
this.averageUpdateDuration_.sample(1, updateDuration);
// Let the caller know how long this update took.
return updateDuration;
}
/**
* Parses the manifest XML. This also handles updates and will update the
* stored manifest.
*
* @param {BufferSource} data
* @param {string} finalManifestUri The final manifest URI, which may
* differ from this.manifestUri_ if there has been a redirect.
* @return {!Promise}
* @private
*/
async parseManifest_(data, finalManifestUri) {
const Error = shaka.util.Error;
const MpdUtils = shaka.dash.MpdUtils;
const mpd = shaka.util.XmlUtils.parseXml(data, 'MPD');
if (!mpd) {
throw new Error(
Error.Severity.CRITICAL, Error.Category.MANIFEST,
Error.Code.DASH_INVALID_XML, finalManifestUri);
}
const disableXlinkProcessing = this.config_.dash.disableXlinkProcessing;
if (disableXlinkProcessing) {
return this.processManifest_(mpd, finalManifestUri);
}
// Process the mpd to account for xlink connections.
const failGracefully = this.config_.dash.xlinkFailGracefully;
const xlinkOperation = MpdUtils.processXlinks(
mpd, this.config_.retryParameters, failGracefully, finalManifestUri,
this.playerInterface_.networkingEngine);
this.operationManager_.manage(xlinkOperation);
const finalMpd = await xlinkOperation.promise;
return this.processManifest_(finalMpd, finalManifestUri);
}
/**
* Takes a formatted MPD and converts it into a manifest.
*
* @param {!Element} mpd
* @param {string} finalManifestUri The final manifest URI, which may
* differ from this.manifestUri_ if there has been a redirect.
* @return {!Promise}
* @private
*/
async processManifest_(mpd, finalManifestUri) {
const Functional = shaka.util.Functional;
const XmlUtils = shaka.util.XmlUtils;
const manifestPreprocessor = this.config_.dash.manifestPreprocessor;
if (manifestPreprocessor) {
manifestPreprocessor(mpd);
}
// Get any Location elements. This will update the manifest location and
// the base URI.
/** @type {!Array.<string>} */
let manifestBaseUris = [finalManifestUri];
/** @type {!Array.<string>} */
const locations = XmlUtils.findChildren(mpd, 'Location')
.map(XmlUtils.getContents)
.filter(Functional.isNotNull);
if (locations.length > 0) {
const absoluteLocations = shaka.util.ManifestParserUtils.resolveUris(
manifestBaseUris, locations);
this.manifestUris_ = absoluteLocations;
manifestBaseUris = absoluteLocations;
}
const uriObjs = XmlUtils.findChildren(mpd, 'BaseURL');
const uris = uriObjs.map(XmlUtils.getContents);
const baseUris = shaka.util.ManifestParserUtils.resolveUris(
manifestBaseUris, uris);
let availabilityTimeOffset = 0;
if (uriObjs && uriObjs.length) {
availabilityTimeOffset = XmlUtils.parseAttr(
uriObjs[0], 'availabilityTimeOffset', XmlUtils.parseFloat) || 0;
}
const ignoreMinBufferTime = this.config_.dash.ignoreMinBufferTime;
let minBufferTime = 0;
if (!ignoreMinBufferTime) {
minBufferTime =
XmlUtils.parseAttr(mpd, 'minBufferTime', XmlUtils.parseDuration) || 0;
}
this.updatePeriod_ = /** @type {number} */ (XmlUtils.parseAttr(
mpd, 'minimumUpdatePeriod', XmlUtils.parseDuration, -1));
const presentationStartTime = XmlUtils.parseAttr(
mpd, 'availabilityStartTime', XmlUtils.parseDate);
let segmentAvailabilityDuration = XmlUtils.parseAttr(
mpd, 'timeShiftBufferDepth', XmlUtils.parseDuration);
const ignoreSuggestedPresentationDelay =
this.config_.dash.ignoreSuggestedPresentationDelay;
let suggestedPresentationDelay = null;
if (!ignoreSuggestedPresentationDelay) {
suggestedPresentationDelay = XmlUtils.parseAttr(
mpd, 'suggestedPresentationDelay', XmlUtils.parseDuration);
}
const ignoreMaxSegmentDuration =
this.config_.dash.ignoreMaxSegmentDuration;
let maxSegmentDuration = null;
if (!ignoreMaxSegmentDuration) {
maxSegmentDuration = XmlUtils.parseAttr(
mpd, 'maxSegmentDuration', XmlUtils.parseDuration);
}
const mpdType = mpd.getAttribute('type') || 'static';
/** @type {!shaka.media.PresentationTimeline} */
let presentationTimeline;
if (this.manifest_) {
presentationTimeline = this.manifest_.presentationTimeline;
// Before processing an update, evict from all segment indexes. Some of
// them may not get updated otherwise if their corresponding Period
// element has been dropped from the manifest since the last update.
// Without this, playback will still work, but this is necessary to
// maintain conditions that we assert on for multi-Period content.
// This gives us confidence that our state is maintained correctly, and
// that the complex logic of multi-Period eviction and period-flattening
// is correct. See also:
// https://github.com/google/shaka-player/issues/3169#issuecomment-823580634
for (const segmentIndex of Object.values(this.segmentIndexMap_)) {
segmentIndex.evict(presentationTimeline.getSegmentAvailabilityStart());
}
} else {
// DASH IOP v3.0 suggests using a default delay between minBufferTime
// and timeShiftBufferDepth. This is literally the range of all
// feasible choices for the value. Nothing older than
// timeShiftBufferDepth is still available, and anything less than
// minBufferTime will cause buffering issues.
//
// We have decided that our default will be the configured value, or
// 1.5 * minBufferTime if not configured. This is fairly conservative.
// Content providers should provide a suggestedPresentationDelay whenever
// possible to optimize the live streaming experience.
const defaultPresentationDelay =
this.config_.defaultPresentationDelay || minBufferTime * 1.5;
const presentationDelay = suggestedPresentationDelay != null ?
suggestedPresentationDelay : defaultPresentationDelay;
presentationTimeline = new shaka.media.PresentationTimeline(
presentationStartTime, presentationDelay,
this.config_.dash.autoCorrectDrift);
}
const profiles = mpd.getAttribute('profiles') || '';
/** @type {shaka.dash.DashParser.Context} */
const context = {
// Don't base on updatePeriod_ since emsg boxes can cause manifest
// updates.
dynamic: mpdType != 'static',
presentationTimeline: presentationTimeline,
period: null,
periodInfo: null,
adaptationSet: null,
representation: null,
bandwidth: 0,
indexRangeWarningGiven: false,
availabilityTimeOffset: availabilityTimeOffset,
profiles: profiles.split(','),
};
const periodsAndDuration = this.parsePeriods_(context, baseUris, mpd);
const duration = periodsAndDuration.duration;
const periods = periodsAndDuration.periods;
presentationTimeline.setStatic(mpdType == 'static');
if (mpdType == 'static' ||
!periodsAndDuration.durationDerivedFromPeriods) {
// Ignore duration calculated from Period lengths if this is dynamic.
presentationTimeline.setDuration(duration || Infinity);
}
// The segments are available earlier than the availability start time.
// 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.minTotalAvailabilityTimeOffset_ && !this.lowLatencyMode_) {
const autoLowLatencyMode = this.playerInterface_.isAutoLowLatencyMode();
if (autoLowLatencyMode) {
this.playerInterface_.enableLowLatencyMode();
this.lowLatencyMode_ = this.playerInterface_.isLowLatencyMode();
}
}
if (this.lowLatencyMode_) {
presentationTimeline.setAvailabilityTimeOffset(
this.minTotalAvailabilityTimeOffset_);
} else if (this.minTotalAvailabilityTimeOffset_) {
// If the playlist contains AvailabilityTimeOffset value, the
// streaming.lowLatencyMode value should be set to true to stream with low
// latency mode.
shaka.log.alwaysWarn('Low-latency DASH 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.');
}
const isLive = presentationTimeline.isLive();
// If it's live, we check for an override.
if (isLive && !isNaN(this.config_.availabilityWindowOverride)) {
segmentAvailabilityDuration = this.config_.availabilityWindowOverride;
}
// If it's null, that means segments are always available. This is always
// the case for VOD, and sometimes the case for live.
if (segmentAvailabilityDuration == null) {
segmentAvailabilityDuration = Infinity;
}
presentationTimeline.setSegmentAvailabilityDuration(
segmentAvailabilityDuration);
// Use @maxSegmentDuration to override smaller, derived values.
presentationTimeline.notifyMaxSegmentDuration(maxSegmentDuration || 1);
if (goog.DEBUG) {
presentationTimeline.assertIsValid();
}
await this.periodCombiner_.combinePeriods(periods, context.dynamic);
// These steps are not done on manifest update.
if (!this.manifest_) {
this.manifest_ = {
presentationTimeline: presentationTimeline,
variants: this.periodCombiner_.getVariants(),
textStreams: this.periodCombiner_.getTextStreams(),
imageStreams: this.periodCombiner_.getImageStreams(),
offlineSessionIds: [],
minBufferTime: minBufferTime || 0,
};
// We only need to do clock sync when we're using presentation start
// time. This condition also excludes VOD streams.
if (presentationTimeline.usingPresentationStartTime()) {
const XmlUtils = shaka.util.XmlUtils;
const timingElements = XmlUtils.findChildren(mpd, 'UTCTiming');
const offset = await this.parseUtcTiming_(baseUris, timingElements);
// Detect calls to stop().
if (!this.playerInterface_) {
return;
}
presentationTimeline.setClockOffset(offset);
}
} else {
// Just update the variants and text streams, which may change as periods
// are added or removed.
this.manifest_.variants = this.periodCombiner_.getVariants();
this.manifest_.textStreams = this.periodCombiner_.getTextStreams();
this.manifest_.imageStreams = this.periodCombiner_.getImageStreams();
// Re-filter the manifest. This will check any configured restrictions on
// new variants, and will pass any new init data to DrmEngine to ensure
// that key rotation works correctly.
this.playerInterface_.filter(this.manifest_);
}
// Add text streams to correspond to closed captions. This happens right
// after period combining, while we still have a direct reference, so that
// any new streams will appear in the period combiner.
this.playerInterface_.makeTextStreamsForClosedCaptions(this.manifest_);
}
/**
* Reads and parses the periods from the manifest. This first does some
* partial parsing so the start and duration is available when parsing
* children.
*
* @param {shaka.dash.DashParser.Context} context
* @param {!Array.<string>} baseUris
* @param {!Element} mpd
* @return {{
* periods: !Array.<shaka.util.PeriodCombiner.Period>,
* duration: ?number,
* durationDerivedFromPeriods: boolean
* }}
* @private
*/
parsePeriods_(context, baseUris, mpd) {
const XmlUtils = shaka.util.XmlUtils;
const presentationDuration = XmlUtils.parseAttr(
mpd, 'mediaPresentationDuration', XmlUtils.parseDuration);
const periods = [];
let prevEnd = 0;
const periodNodes = XmlUtils.findChildren(mpd, 'Period');
// This uses a for-loop rather than a for-of loop because this needs to look
// ahead to the next element.
const enumerate = (it) => shaka.util.Iterables.enumerate(it);
for (const {i, item: elem, next} of enumerate(periodNodes)) {
const start = /** @type {number} */ (
XmlUtils.parseAttr(elem, 'start', XmlUtils.parseDuration, prevEnd));
const givenDuration =
XmlUtils.parseAttr(elem, 'duration', XmlUtils.parseDuration);
let periodDuration = null;
if (next) {
// "The difference between the start time of a Period and the start time
// of the following Period is the duration of the media content
// represented by this Period."
const nextStart =
XmlUtils.parseAttr(next, 'start', XmlUtils.parseDuration);
if (nextStart != null) {
periodDuration = nextStart - start;
}
} else if (presentationDuration != null) {
// "The Period extends until the Period.start of the next Period, or
// until the end of the Media Presentation in the case of the last
// Period."
periodDuration = presentationDuration - start;
}
const threshold =
shaka.util.ManifestParserUtils.GAP_OVERLAP_TOLERANCE_SECONDS;
if (periodDuration && givenDuration &&
Math.abs(periodDuration - givenDuration) > threshold) {
shaka.log.warning('There is a gap/overlap between Periods', elem);
}
// Only use the @duration in the MPD if we can't calculate it. We should
// favor the @start of the following Period. This ensures that there
// aren't gaps between Periods.
if (periodDuration == null) {
periodDuration = givenDuration;
}
// Skip all periods with start time < maximum period start time, excepts
// the last period in manifest
if (this.largestPeriodStartTime_ !== null && start !== null &&
start < this.largestPeriodStartTime_ &&
i + 1 != periodNodes.length) {
shaka.log.debug(
'Skipping Period', i + 1, ' as its start time is smaller than ' +
'the largest period start time that has been seen.');
continue;
}
// Save maximum period start time if it is the last period
if (start !== null &&
(this.largestPeriodStartTime_ === null ||
start > this.largestPeriodStartTime_)) {
this.largestPeriodStartTime_ = start;
}
// Parse child nodes.
const info = {
start: start,
duration: periodDuration,
node: elem,
isLastPeriod: periodDuration == null || !next,
};
const period = this.parsePeriod_(context, baseUris, info);
periods.push(period);
if (context.period.id && periodDuration) {
this.periodDurations_[context.period.id] = periodDuration;
}
if (periodDuration == null) {
if (next) {
// If the duration is still null and we aren't at the end, then we
// will skip any remaining periods.
shaka.log.warning(
'Skipping Period', i + 1, 'and any subsequent Periods:', 'Period',
i + 1, 'does not have a valid start time.', next);
}
// The duration is unknown, so the end is unknown.
prevEnd = null;
break;
}
prevEnd = start + periodDuration;
} // end of period parsing loop
if (presentationDuration != null) {
if (prevEnd != presentationDuration) {
shaka.log.warning(
'@mediaPresentationDuration does not match the total duration of ',
'all Periods.');
// Assume @mediaPresentationDuration is correct.
}
return {
periods: periods,
duration: presentationDuration,
durationDerivedFromPeriods: false,
};
} else {
return {
periods: periods,
duration: prevEnd,
durationDerivedFromPeriods: true,
};
}
}
/**
* Parses a Period XML element. Unlike the other parse methods, this is not
* given the Node; it is given a PeriodInfo structure. Also, partial parsing
* was done before this was called so start and duration are valid.
*
* @param {shaka.dash.DashParser.Context} context
* @param {!Array.<string>} baseUris
* @param {shaka.dash.DashParser.PeriodInfo} periodInfo
* @return {shaka.util.PeriodCombiner.Period}
* @private
*/
parsePeriod_(context, baseUris, periodInfo) {
const Functional = shaka.util.Functional;
const XmlUtils = shaka.util.XmlUtils;
const ContentType = shaka.util.ManifestParserUtils.ContentType;
context.period = this.createFrame_(periodInfo.node, null, baseUris);
context.periodInfo = periodInfo;
context.period.availabilityTimeOffset = context.availabilityTimeOffset;
// If the period doesn't have an ID, give it one based on its start time.
if (!context.period.id) {
shaka.log.info(
'No Period ID given for Period with start time ' + periodInfo.start +
', Assigning a default');
context.period.id = '__shaka_period_' + periodInfo.start;
}
const eventStreamNodes =
XmlUtils.findChildren(periodInfo.node, 'EventStream');
for (const node of eventStreamNodes) {
this.parseEventStream_(periodInfo.start, periodInfo.duration, node);
}
const adaptationSetNodes =
XmlUtils.findChildren(periodInfo.node, 'AdaptationSet');
const adaptationSets = adaptationSetNodes
.map((node) => this.parseAdaptationSet_(context, node))
.filter(Functional.isNotNull);
// For dynamic manifests, we use rep IDs internally, and they must be
// unique.
if (context.dynamic) {
const ids = [];
for (const set of adaptationSets) {
for (const id of set.representationIds) {
ids.push(id);
}
}
const uniqueIds = new Set(ids);
if (ids.length != uniqueIds.size) {
throw new shaka.util.Error(
shaka.util.Error.Severity.CRITICAL,
shaka.util.Error.Category.MANIFEST,
shaka.util.Error.Code.DASH_DUPLICATE_REPRESENTATION_ID);
}
}
const normalAdaptationSets = adaptationSets
.filter((as) => { return !as.trickModeFor; });
const trickModeAdaptationSets = adaptationSets
.filter((as) => { return as.trickModeFor; });
// Attach trick mode tracks to normal tracks.
for (const trickModeSet of trickModeAdaptationSets) {
const targetIds = trickModeSet.trickModeFor.split(' ');
for (const normalSet of normalAdaptationSets) {
if (targetIds.includes(normalSet.id)) {
for (const stream of normalSet.streams) {
// There may be multiple trick mode streams, but we do not
// currently support that. Just choose one.
// TODO: https://github.com/google/shaka-player/issues/1528
stream.trickModeVideo = trickModeSet.streams.find((trickStream) =>
shaka.util.MimeUtils.getCodecBase(stream.codecs) ==
shaka.util.MimeUtils.getCodecBase(trickStream.codecs));
}
}
}
}
const audioSets = this.config_.disableAudio ? [] :
this.getSetsOfType_(normalAdaptationSets, ContentType.AUDIO);
const videoSets = this.config_.disableVideo ? [] :
this.getSetsOfType_(normalAdaptationSets, ContentType.VIDEO);
const textSets = this.config_.disableText ? [] :
this.getSetsOfType_(normalAdaptationSets, ContentType.TEXT);
const imageSets = this.config_.disableThumbnails ? [] :
this.getSetsOfType_(normalAdaptationSets, ContentType.IMAGE);
if (!videoSets.length && !audioSets.length) {
throw new shaka.util.Error(
shaka.util.Error.Severity.CRITICAL,
shaka.util.Error.Category.MANIFEST,
shaka.util.Error.Code.DASH_EMPTY_PERIOD);
}
const audioStreams = [];
for (const audioSet of audioSets) {
audioStreams.push(...audioSet.streams);
}
const videoStreams = [];
for (const videoSet of videoSets) {
videoStreams.push(...videoSet.streams);
}
const textStreams = [];
for (const textSet of textSets) {
textStreams.push(...textSet.streams);
}
const imageStreams = [];
for (const imageSet of imageSets) {
imageStreams.push(...imageSet.streams);
}
return {
id: context.period.id,
audioStreams,
videoStreams,
textStreams,
imageStreams,
};
}
/**
* @param {!Array.<!shaka.dash.DashParser.AdaptationInfo>} adaptationSets
* @param {string} type
* @return {!Array.<!shaka.dash.DashParser.AdaptationInfo>}
* @private
*/
getSetsOfType_(adaptationSets, type) {
return adaptationSets.filter((as) => {
return as.contentType == type;
});
}
/**
* Parses an AdaptationSet XML element.
*
* @param {shaka.dash.DashParser.Context} context
* @param {!Element} elem The AdaptationSet element.
* @return {?shaka.dash.DashParser.AdaptationInfo}
* @private
*/
parseAdaptationSet_(context, elem) {
const XmlUtils = shaka.util.XmlUtils;
const Functional = shaka.util.Functional;
const ManifestParserUtils = shaka.util.ManifestParserUtils;
const ContentType = ManifestParserUtils.ContentType;
const ContentProtection = shaka.dash.ContentProtection;
context.adaptationSet = this.createFrame_(elem, context.period, null);
let main = false;
const roleElements = XmlUtils.findChildren(elem, 'Role');
const roleValues = roleElements.map((role) => {
return role.getAttribute('value');
}).filter(Functional.isNotNull);
// Default kind for text streams is 'subtitle' if unspecified in the
// manifest.
let kind = undefined;
const isText = context.adaptationSet.contentType == ContentType.TEXT;
if (isText) {
kind = ManifestParserUtils.TextStreamKind.SUBTITLE;
}
for (const roleElement of roleElements) {
const scheme = roleElement.getAttribute('schemeIdUri');
if (scheme == null || scheme == 'urn:mpeg:dash:role:2011') {
// These only apply for the given scheme, but allow them to be specified
// if there is no scheme specified.
// See: DASH section 5.8.5.5
const value = roleElement.getAttribute('value');
switch (value) {
case 'main':
main = true;
break;
case 'caption':
case 'subtitle':
kind = value;
break;
}
}
}
const essentialProperties =
XmlUtils.findChildren(elem, 'EssentialProperty');
// ID of real AdaptationSet if this is a trick mode set:
let trickModeFor = null;
let unrecognizedEssentialProperty = false;
for (const prop of essentialProperties) {
const schemeId = prop.getAttribute('schemeIdUri');
if (schemeId == 'http://dashif.org/guidelines/trickmode') {
trickModeFor = prop.getAttribute('value');
} else {
unrecognizedEssentialProperty = true;
}
}
const accessibilities = XmlUtils.findChildren(elem, 'Accessibility');
const LanguageUtils = shaka.util.LanguageUtils;
const closedCaptions = new Map();
for (const prop of accessibilities) {
const schemeId = prop.getAttribute('schemeIdUri');
const value = prop.getAttribute('value');
if (schemeId == 'urn:scte:dash:cc:cea-608:2015' ) {
let channelId = 1;
if (value != null) {
const channelAssignments = value.split(';');
for (const captionStr of channelAssignments) {
let channel;
let language;
// Some closed caption descriptions have channel number and
// language ("CC1=eng") others may only have language ("eng,spa").
if (!captionStr.includes('=')) {
// When the channel assignemnts are not explicitly provided and
// there are only 2 values provided, it is highly likely that the
// assignments are CC1 and CC3 (most commonly used CC streams).
// Otherwise, cycle through all channels arbitrarily (CC1 - CC4)
// in order of provided langs.
channel = `CC${channelId}`;
if (channelAssignments.length == 2) {
channelId += 2;
} else {
channelId ++;
}
language = captionStr;
} else {
const channelAndLanguage = captionStr.split('=');
// The channel info can be '1' or 'CC1'.
// If the channel info only has channel number(like '1'), add 'CC'
// as prefix so that it can be a full channel id (like 'CC1').
channel = channelAndLanguage[0].startsWith('CC') ?
channelAndLanguage[0] : `CC${channelAndLanguage[0]}`;
// 3 letters (ISO 639-2). In b/187442669, we saw a blank string
// (CC2=;CC3=), so default to "und" (the code for "undetermined").
language = channelAndLanguage[1] || 'und';
}
closedCaptions.set(channel, LanguageUtils.normalize(language));
}
} else {
// If channel and language information has not been provided, assign
// 'CC1' as channel id and 'und' as language info.
closedCaptions.set('CC1', 'und');
}
} else if (schemeId == 'urn:scte:dash:cc:cea-708:2015') {
let serviceNumber = 1;
if (value != null) {
for (const captionStr of value.split(';')) {
let service;
let language;
// Similar to CEA-608, it is possible that service # assignments
// are not explicitly provided e.g. "eng;deu;swe" In this case,
// we just cycle through the services for each language one by one.
if (!captionStr.includes('=')) {
service = `svc${serviceNumber}`;
serviceNumber ++;
language = captionStr;
} else {
// Otherwise, CEA-708 caption values take the form "
// 1=lang:eng;2=lang:deu" i.e. serviceNumber=lang:threelettercode.
const serviceAndLanguage = captionStr.split('=');
service = `svc${serviceAndLanguage[0]}`;
// The language info can be different formats, lang:eng',
// or 'lang:eng,war:1,er:1'. Extract the language info.
language = serviceAndLanguage[1].split(',')[0].split(':').pop();
}
closedCaptions.set(service, LanguageUtils.normalize(language));
}
} else {
// If service and language information has not been provided, assign
// 'svc1' as service number and 'und' as language info.
closedCaptions.set('svc1', 'und');
}
} else if (schemeId == 'urn:mpeg:dash:role:2011') {
// See DASH IOP 3.9.2 Table 4.
if (value != null) {
roleValues.push(value);
if (value == 'captions') {
kind = ManifestParserUtils.TextStreamKind.CLOSED_CAPTION;
}
}
}
}
// According to DASH spec (2014) section 5.8.4.8, "the successful processing
// of the descriptor is essential to properly use the information in the
// parent element". According to DASH IOP v3.3, section 3.3.4, "if the
// scheme or the value" for EssentialProperty is not recognized, "the DASH
// client shall ignore the parent element."
if (unrecognizedEssentialProperty) {
// Stop parsing this AdaptationSet and let the caller filter out the
// nulls.
return null;
}
const contentProtectionElems =
XmlUtils.findChildren(elem, 'ContentProtection');
const contentProtection = ContentProtection.parseFromAdaptationSet(
contentProtectionElems,
this.config_.dash.ignoreDrmInfo,
this.config_.dash.keySystemsByURI);
const language =
shaka.util.LanguageUtils.normalize(elem.getAttribute('lang') || 'und');
// This attribute is currently non-standard, but it is supported by Kaltura.
let label = elem.getAttribute('label');
// See DASH IOP 4.3 here https://dashif.org/docs/DASH-IF-IOP-v4.3.pdf (page 35)
const labelElements = XmlUtils.findChildren(elem, 'Label');
if (labelElements && labelElements.length) {
// NOTE: Right now only one label field is supported.
const firstLabelElement = labelElements[0];
if (firstLabelElement.textContent) {
label = firstLabelElement.textContent;
}
}
// Parse Representations into Streams.
const representations = XmlUtils.findChildren(elem, 'Representation');
const streams = representations.map((representation) => {
return this.parseRepresentation_(context, contentProtection, kind,
language, label, main, roleValues, closedCaptions, representation);
}).filter((s) => !!s);
if (streams.length == 0) {
const isImage = context.adaptationSet.contentType == ContentType.IMAGE;
// Ignore empty AdaptationSets if ignoreEmptyAdaptationSet is true
// or they are for text/image content.
if (this.config_.dash.ignoreEmptyAdaptationSet || isText || isImage) {
return null;
}
throw new shaka.util.Error(
shaka.util.Error.Severity.CRITICAL,
shaka.util.Error.Category.MANIFEST,
shaka.util.Error.Code.DASH_EMPTY_ADAPTATION_SET);
}
// If AdaptationSet's type is unknown or is ambiguously "application",
// guess based on the information in the first stream. If the attributes
// mimeType and codecs are split across levels, they will both be inherited
// down to the stream level by this point, so the stream will have all the
// necessary information.