/*! @license * Shaka Player * Copyright 2016 Google LLC * SPDX-License-Identifier: Apache-2.0 */goog.provide('shaka.dash.SegmentTemplate');goog.require('goog.asserts');goog.require('shaka.dash.MpdUtils');goog.require('shaka.dash.SegmentBase');goog.require('shaka.log');goog.require('shaka.media.InitSegmentReference');goog.require('shaka.media.SegmentIndex');goog.require('shaka.media.SegmentReference');goog.require('shaka.util.Error');goog.require('shaka.util.IReleasable');goog.require('shaka.util.ManifestParserUtils');goog.require('shaka.util.ObjectUtils');goog.require('shaka.util.StringUtils');goog.requireType('shaka.dash.DashParser');goog.requireType('shaka.media.PresentationTimeline');/** * @summary A set of functions for parsing SegmentTemplate elements. */shaka.dash.SegmentTemplate = class { /** * Creates a new StreamInfo object. * Updates the existing SegmentIndex, if any. * * @param {shaka.dash.DashParser.Context} context * @param {shaka.dash.DashParser.RequestSegmentCallback} requestSegment * @param {!Object.<string, !shaka.extern.Stream>} streamMap * @param {boolean} isUpdate True if the manifest is being updated. * @param {number} segmentLimit The maximum number of segments to generate for * a SegmentTemplate with fixed duration. * @param {!Object.<string, number>} periodDurationMap * @param {shaka.extern.aesKey|undefined} aesKey * @param {?number} lastSegmentNumber * @return {shaka.dash.DashParser.StreamInfo} */ static createStreamInfo( context, requestSegment, streamMap, isUpdate, segmentLimit, periodDurationMap, aesKey, lastSegmentNumber) { goog.asserts.assert(context.representation.segmentTemplate, 'Should only be called with SegmentTemplate'); const SegmentTemplate = shaka.dash.SegmentTemplate; const TimelineSegmentIndex = shaka.dash.TimelineSegmentIndex; const initSegmentReference = SegmentTemplate.createInitSegment_(context, aesKey); /** @type {shaka.dash.SegmentTemplate.SegmentTemplateInfo} */ const info = SegmentTemplate.parseSegmentTemplateInfo_(context); SegmentTemplate.checkSegmentTemplateInfo_(context, info); // Direct fields of context will be reassigned by the parser before // generateSegmentIndex is called. So we must make a shallow copy first, // and use that in the generateSegmentIndex callbacks. const shallowCopyOfContext = shaka.util.ObjectUtils.shallowCloneObject(context); if (info.indexTemplate) { shaka.dash.SegmentBase.checkSegmentIndexSupport( context, initSegmentReference); return { generateSegmentIndex: () => { return SegmentTemplate.generateSegmentIndexFromIndexTemplate_( shallowCopyOfContext, requestSegment, initSegmentReference, info); }, }; } else if (info.segmentDuration) { if (!isUpdate && context.adaptationSet.contentType !== 'image') { context.presentationTimeline.notifyMaxSegmentDuration( info.segmentDuration); context.presentationTimeline.notifyMinSegmentStartTime( context.periodInfo.start); } return { generateSegmentIndex: () => { return SegmentTemplate.generateSegmentIndexFromDuration_( shallowCopyOfContext, info, segmentLimit, initSegmentReference, periodDurationMap, aesKey, lastSegmentNumber); }, }; } else { /** @type {shaka.media.SegmentIndex} */ let segmentIndex = null; let id = null; let stream = null; if (context.period.id && context.representation.id) { // Only check/store the index if period and representation IDs are set. id = context.period.id + ',' + context.representation.id; stream = streamMap[id]; if (stream) { segmentIndex = stream.segmentIndex; } } const periodStart = context.periodInfo.start; const periodEnd = context.periodInfo.duration ? periodStart + context.periodInfo.duration : Infinity; shaka.log.debug(`New manifest ${periodStart} - ${periodEnd}`); /* When to fit segments. All refactors should honor/update this table: * * | dynamic | infinite | last | should | notes | * | | period | period | fit | | * | ------- | -------- | ------ | ------ | ------------------------- | * | F | F | X | T | typical VOD | * | F | T | X | X | impossible: infinite VOD | * | T | F | F | T | typical live, old period | * | T | F | T | F | typical IPR | * | T | T | F | X | impossible: old, infinite | * | T | T | T | F | typical live, new period | */ // We never fit the final period of dynamic content, which could be // infinite live (with no limit to fit to) or IPR (which would expand the // most recent segment to the end of the presentation). const shouldFit = !(context.dynamic && context.periodInfo.isLastPeriod); if (!segmentIndex) { shaka.log.debug(`Creating TSI with end ${periodEnd}`); segmentIndex = new TimelineSegmentIndex( info, context.representation.id, context.bandwidth, context.representation.getBaseUris, periodStart, periodEnd, initSegmentReference, shouldFit, aesKey, context.representation.segmentSequenceCadence, ); } else { const tsi = /** @type {!TimelineSegmentIndex} */(segmentIndex); tsi.appendTemplateInfo( info, periodStart, periodEnd, shouldFit, initSegmentReference); const availabilityStart = context.presentationTimeline.getSegmentAvailabilityStart(); tsi.evict(availabilityStart); } if (info.timeline && context.adaptationSet.contentType !== 'image') { const timeline = info.timeline; context.presentationTimeline.notifyTimeRange( timeline, periodStart); } if (stream && context.dynamic) { stream.segmentIndex = segmentIndex; } return { generateSegmentIndex: () => { // If segmentIndex is deleted, or segmentIndex's references are // released by closeSegmentIndex(), we should set the value of // segmentIndex again. if (segmentIndex instanceof shaka.dash.TimelineSegmentIndex && segmentIndex.isEmpty()) { segmentIndex.appendTemplateInfo(info, periodStart, periodEnd, shouldFit, initSegmentReference); } return Promise.resolve(segmentIndex); }, }; } } /** * @param {?shaka.dash.DashParser.InheritanceFrame} frame * @return {?shaka.extern.xml.Node} * @private */ static fromInheritance_(frame) { return frame.segmentTemplate; } /** * Parses a SegmentTemplate element into an info object. * * @param {shaka.dash.DashParser.Context} context * @return {shaka.dash.SegmentTemplate.SegmentTemplateInfo} * @private */ static parseSegmentTemplateInfo_(context) { const SegmentTemplate = shaka.dash.SegmentTemplate; const MpdUtils = shaka.dash.MpdUtils; const StringUtils = shaka.util.StringUtils; const segmentInfo = MpdUtils.parseSegmentInfo(context, SegmentTemplate.fromInheritance_); const media = MpdUtils.inheritAttribute( context, SegmentTemplate.fromInheritance_, 'media'); const index = MpdUtils.inheritAttribute( context, SegmentTemplate.fromInheritance_, 'index'); return { segmentDuration: segmentInfo.segmentDuration, timescale: segmentInfo.timescale, startNumber: segmentInfo.startNumber, scaledPresentationTimeOffset: segmentInfo.scaledPresentationTimeOffset, unscaledPresentationTimeOffset: segmentInfo.unscaledPresentationTimeOffset, timeline: segmentInfo.timeline, mediaTemplate: media && StringUtils.htmlUnescape(media), indexTemplate: index, mimeType: context.representation.mimeType, codecs: context.representation.codecs, }; } /** * Verifies a SegmentTemplate info object. * * @param {shaka.dash.DashParser.Context} context * @param {shaka.dash.SegmentTemplate.SegmentTemplateInfo} info * @private */ static checkSegmentTemplateInfo_(context, info) { let n = 0; n += info.indexTemplate ? 1 : 0; n += info.timeline ? 1 : 0; n += info.segmentDuration ? 1 : 0; if (n == 0) { shaka.log.error( 'SegmentTemplate does not contain any segment information:', 'the SegmentTemplate must contain either an index URL template', 'a SegmentTimeline, or a segment duration.', context.representation); throw new shaka.util.Error( shaka.util.Error.Severity.CRITICAL, shaka.util.Error.Category.MANIFEST, shaka.util.Error.Code.DASH_NO_SEGMENT_INFO); } else if (n != 1) { shaka.log.warning( 'SegmentTemplate containes multiple segment information sources:', 'the SegmentTemplate should only contain an index URL template,', 'a SegmentTimeline or a segment duration.', context.representation); if (info.indexTemplate) { shaka.log.info('Using the index URL template by default.'); info.timeline = null; info.segmentDuration = null; } else { goog.asserts.assert(info.timeline, 'There should be a timeline'); shaka.log.info('Using the SegmentTimeline by default.'); info.segmentDuration = null; } } if (!info.indexTemplate && !info.mediaTemplate) { shaka.log.error( 'SegmentTemplate does not contain sufficient segment information:', 'the SegmentTemplate\'s media URL template is missing.', context.representation); throw new shaka.util.Error( shaka.util.Error.Severity.CRITICAL, shaka.util.Error.Category.MANIFEST, shaka.util.Error.Code.DASH_NO_SEGMENT_INFO); } } /** * Generates a SegmentIndex from an index URL template. * * @param {shaka.dash.DashParser.Context} context * @param {shaka.dash.DashParser.RequestSegmentCallback} requestSegment * @param {shaka.media.InitSegmentReference} init * @param {shaka.dash.SegmentTemplate.SegmentTemplateInfo} info * @return {!Promise.<shaka.media.SegmentIndex>} * @private */ static generateSegmentIndexFromIndexTemplate_( context, requestSegment, init, info) { const MpdUtils = shaka.dash.MpdUtils; const ManifestParserUtils = shaka.util.ManifestParserUtils; goog.asserts.assert(info.indexTemplate, 'must be using index template'); const filledTemplate = MpdUtils.fillUriTemplate( info.indexTemplate, context.representation.id, null, null, context.bandwidth || null, null); const resolvedUris = ManifestParserUtils.resolveUris( context.representation.getBaseUris(), [filledTemplate]); return shaka.dash.SegmentBase.generateSegmentIndexFromUris( context, requestSegment, init, resolvedUris, 0, null, info.scaledPresentationTimeOffset); } /** * Generates a SegmentIndex from fixed-duration segments. * * @param {shaka.dash.DashParser.Context} context * @param {shaka.dash.SegmentTemplate.SegmentTemplateInfo} info * @param {number} segmentLimit The maximum number of segments to generate. * @param {shaka.media.InitSegmentReference} initSegmentReference * @param {!Object.<string, number>} periodDurationMap * @param {shaka.extern.aesKey|undefined} aesKey * @param {?number} lastSegmentNumber * @return {!Promise.<shaka.media.SegmentIndex>} * @private */ static generateSegmentIndexFromDuration_( context, info, segmentLimit, initSegmentReference, periodDurationMap, aesKey, lastSegmentNumber) { goog.asserts.assert(info.mediaTemplate, 'There should be a media template with duration'); const MpdUtils = shaka.dash.MpdUtils; const ManifestParserUtils = shaka.util.ManifestParserUtils; const presentationTimeline = context.presentationTimeline; // Capture values that could change as the parsing context moves on to // other parts of the manifest. const periodStart = context.periodInfo.start; const periodId = context.period.id; const initialPeriodDuration = context.periodInfo.duration; // For multi-period live streams the period duration may not be known until // the following period appears in an updated manifest. periodDurationMap // provides the updated period duration. const getPeriodEnd = () => { const periodDuration = (periodId != null && periodDurationMap[periodId]) || initialPeriodDuration; const periodEnd = periodDuration ? (periodStart + periodDuration) : Infinity; return periodEnd; }; const segmentDuration = info.segmentDuration; goog.asserts.assert( segmentDuration != null, 'Segment duration must not be null!'); const startNumber = info.startNumber; const timescale = info.timescale; const template = info.mediaTemplate; const bandwidth = context.bandwidth || null; const id = context.representation.id; const getBaseUris = context.representation.getBaseUris; const timestampOffset = periodStart - info.scaledPresentationTimeOffset; // Computes the range of presentation timestamps both within the period and // available. This is an intersection of the period range and the // availability window. const computeAvailablePeriodRange = () => { return [ Math.max( presentationTimeline.getSegmentAvailabilityStart(), periodStart), Math.min( presentationTimeline.getSegmentAvailabilityEnd(), getPeriodEnd()), ]; }; // Computes the range of absolute positions both within the period and // available. The range is inclusive. These are the positions for which we // will generate segment references. const computeAvailablePositionRange = () => { // In presentation timestamps. const availablePresentationTimes = computeAvailablePeriodRange(); goog.asserts.assert(availablePresentationTimes.every(isFinite), 'Available presentation times must be finite!'); goog.asserts.assert(availablePresentationTimes.every((x) => x >= 0), 'Available presentation times must be positive!'); goog.asserts.assert(segmentDuration != null, 'Segment duration must not be null!'); // In period-relative timestamps. const availablePeriodTimes = availablePresentationTimes.map((x) => x - periodStart); // These may sometimes be reversed ([1] <= [0]) if the period is // completely unavailable. The logic will still work if this happens, // because we will simply generate no references. // In period-relative positions (0-based). const availablePeriodPositions = [ Math.ceil(availablePeriodTimes[0] / segmentDuration), Math.ceil(availablePeriodTimes[1] / segmentDuration) - 1, ]; // For Low Latency we can request the partial current position. if (context.representation.availabilityTimeOffset) { availablePeriodPositions[1]++; } // In absolute positions. const availablePresentationPositions = availablePeriodPositions.map((x) => x + startNumber); return availablePresentationPositions; }; // For Live, we must limit the initial SegmentIndex in size, to avoid // consuming too much CPU or memory for content with gigantic // timeShiftBufferDepth (which can have values up to and including // Infinity). const range = computeAvailablePositionRange(); const minPosition = context.dynamic ? Math.max(range[0], range[1] - segmentLimit + 1) : range[0]; const maxPosition = lastSegmentNumber || range[1]; const references = []; const createReference = (position) => { // These inner variables are all scoped to the inner loop, and can be used // safely in the callback below. goog.asserts.assert(segmentDuration != null, 'Segment duration must not be null!'); // Relative to the period start. const positionWithinPeriod = position - startNumber; const segmentPeriodTime = positionWithinPeriod * segmentDuration; // What will appear in the actual segment files. The media timestamp is // what is expected in the $Time$ template. const segmentMediaTime = segmentPeriodTime + info.scaledPresentationTimeOffset; const getUris = () => { let time = segmentMediaTime * timescale; if ('BigInt' in window && time > Number.MAX_SAFE_INTEGER) { time = BigInt(segmentMediaTime) * BigInt(timescale); } const mediaUri = MpdUtils.fillUriTemplate( template, id, position, /* subNumber= */ null, bandwidth, time); return ManifestParserUtils.resolveUris(getBaseUris(), [mediaUri]); }; // Relative to the presentation. const segmentStart = segmentPeriodTime + periodStart; const trueSegmentEnd = segmentStart + segmentDuration; // Cap the segment end at the period end so that references from the // next period will fit neatly after it. const segmentEnd = Math.min(trueSegmentEnd, getPeriodEnd()); // This condition will be true unless the segmentStart was >= periodEnd. // If we've done the position calculations correctly, this won't happen. goog.asserts.assert(segmentStart < segmentEnd, 'Generated a segment outside of the period!'); const ref = new shaka.media.SegmentReference( segmentStart, segmentEnd, getUris, /* startByte= */ 0, /* endByte= */ null, initSegmentReference, timestampOffset, /* appendWindowStart= */ periodStart, /* appendWindowEnd= */ getPeriodEnd(), /* partialReferences= */ [], /* tilesLayout= */ '', /* tileDuration= */ null, /* syncTime= */ null, shaka.media.SegmentReference.Status.AVAILABLE, aesKey); ref.codecs = context.representation.codecs; ref.mimeType = context.representation.mimeType; // This is necessary information for thumbnail streams: ref.trueEndTime = trueSegmentEnd; return ref; }; for (let position = minPosition; position <= maxPosition; ++position) { const reference = createReference(position); references.push(reference); } /** @type {shaka.media.SegmentIndex} */ const segmentIndex = new shaka.media.SegmentIndex(references); // If the availability timeline currently ends before the period, we will // need to add references over time. const willNeedToAddReferences = presentationTimeline.getSegmentAvailabilityEnd() < getPeriodEnd(); // When we start a live stream with a period that ends within the // availability window we will not need to add more references, but we will // need to evict old references. const willNeedToEvictReferences = presentationTimeline.isLive(); if (willNeedToAddReferences || willNeedToEvictReferences) { // The period continues to get longer over time, so check for new // references once every |segmentDuration| seconds. // We clamp to |minPosition| in case the initial range was reversed and no // references were generated. Otherwise, the update would start creating // negative positions for segments in periods which begin in the future. let nextPosition = Math.max(minPosition, maxPosition + 1); let updateTime = segmentDuration; // For low latency we need to evict very frequently. if (context.representation.availabilityTimeOffset) { updateTime = 0.1; } segmentIndex.updateEvery(updateTime, () => { // Evict any references outside the window. const availabilityStartTime = presentationTimeline.getSegmentAvailabilityStart(); segmentIndex.evict(availabilityStartTime); // Compute any new references that need to be added. const [_, maxPosition] = computeAvailablePositionRange(); const references = []; while (nextPosition <= maxPosition) { const reference = createReference(nextPosition); references.push(reference); nextPosition++; } // The timer must continue firing until the entire period is // unavailable, so that all references will be evicted. if (availabilityStartTime > getPeriodEnd() && !references.length) { // Signal stop. return null; } return references; }); } return Promise.resolve(segmentIndex); } /** * Creates an init segment reference from a context object. * * @param {shaka.dash.DashParser.Context} context * @param {shaka.extern.aesKey|undefined} aesKey * @return {shaka.media.InitSegmentReference} * @private */ static createInitSegment_(context, aesKey) { const MpdUtils = shaka.dash.MpdUtils; const ManifestParserUtils = shaka.util.ManifestParserUtils; const SegmentTemplate = shaka.dash.SegmentTemplate; let initialization = MpdUtils.inheritAttribute( context, SegmentTemplate.fromInheritance_, 'initialization'); if (!initialization) { return null; } initialization = shaka.util.StringUtils.htmlUnescape(initialization); const repId = context.representation.id; const bandwidth = context.bandwidth || null; const getBaseUris = context.representation.getBaseUris; const getUris = () => { goog.asserts.assert(initialization, 'Should have returned earler'); const filledTemplate = MpdUtils.fillUriTemplate( initialization, repId, null, null, bandwidth, null); const resolvedUris = ManifestParserUtils.resolveUris( getBaseUris(), [filledTemplate]); return resolvedUris; }; const qualityInfo = shaka.dash.SegmentBase.createQualityInfo(context); const ref = new shaka.media.InitSegmentReference( getUris, /* startByte= */ 0, /* endByte= */ null, qualityInfo, /* timescale= */ null, /* segmentData= */ null, aesKey); ref.codecs = context.representation.codecs; ref.mimeType = context.representation.mimeType; return ref; }};/** * A SegmentIndex that returns segments references on demand from * a segment timeline. * * @extends shaka.media.SegmentIndex * @implements {shaka.util.IReleasable} * @implements {Iterable.<!shaka.media.SegmentReference>} * * @private * */shaka.dash.TimelineSegmentIndex = class extends shaka.media.SegmentIndex { /** * * @param {!shaka.dash.SegmentTemplate.SegmentTemplateInfo} templateInfo * @param {?string} representationId * @param {number} bandwidth * @param {function():Array.<string>} getBaseUris * @param {number} periodStart * @param {number} periodEnd * @param {shaka.media.InitSegmentReference} initSegmentReference * @param {boolean} shouldFit * @param {shaka.extern.aesKey|undefined} aesKey * @param {number} segmentSequenceCadence */ constructor(templateInfo, representationId, bandwidth, getBaseUris, periodStart, periodEnd, initSegmentReference, shouldFit, aesKey, segmentSequenceCadence) { super([]); /** @private {?shaka.dash.SegmentTemplate.SegmentTemplateInfo} */ this.templateInfo_ = templateInfo; /** @private {?string} */ this.representationId_ = representationId; /** @private {number} */ this.bandwidth_ = bandwidth; /** @private {function():Array.<string>} */ this.getBaseUris_ = getBaseUris; /** @private {number} */ this.periodStart_ = periodStart; /** @private {number} */ this.periodEnd_ = periodEnd; /** @private {shaka.media.InitSegmentReference} */ this.initSegmentReference_ = initSegmentReference; /** @private {shaka.extern.aesKey|undefined} */ this.aesKey_ = aesKey; /** @private {number} */ this.segmentSequenceCadence_ = segmentSequenceCadence; if (shouldFit) { this.fitTimeline(); } } /** * @override */ getNumReferences() { if (this.templateInfo_) { return this.templateInfo_.timeline.length; } else { return 0; } } /** * @override */ release() { super.release(); this.templateInfo_ = null; // We cannot release other fields, as segment index can // be recreated using only template info. } /** * @override */ evict(time) { if (!this.templateInfo_) { return; } shaka.log.debug(`${this.representationId_} Evicting at ${time}`); let numToEvict = 0; const timeline = this.templateInfo_.timeline; for (let i = 0; i < timeline.length; i += 1) { const range = timeline[i]; const end = range.end + this.periodStart_; const start = range.start + this.periodStart_; if (end <= time) { shaka.log.debug(`Evicting ${start} - ${end}`); numToEvict += 1; } else { break; } } if (numToEvict > 0) { this.templateInfo_.timeline = timeline.slice(numToEvict); if (this.references.length >= numToEvict) { this.references = this.references.slice(numToEvict); } this.numEvicted_ += numToEvict; if (this.getNumReferences() === 0) { this.release(); } } } /** * Merge new template info * @param {shaka.dash.SegmentTemplate.SegmentTemplateInfo} info * @param {number} periodStart * @param {number} periodEnd * @param {boolean} shouldFit * @param {shaka.media.InitSegmentReference} initSegmentReference */ appendTemplateInfo(info, periodStart, periodEnd, shouldFit, initSegmentReference) { this.updateInitSegmentReference(initSegmentReference); if (!this.templateInfo_) { this.templateInfo_ = info; this.periodStart_ = periodStart; this.periodEnd_ = periodEnd; } else { const currentTimeline = this.templateInfo_.timeline; this.templateInfo_.mediaTemplate = info.mediaTemplate; // Append timeline const lastCurrentEntry = currentTimeline[currentTimeline.length - 1]; const newEntries = info.timeline.filter((entry) => { return entry.start >= lastCurrentEntry.end; }); if (newEntries.length > 0) { shaka.log.debug(`Appending ${newEntries.length} entries`); this.templateInfo_.timeline.push(...newEntries); } if (this.periodEnd_ !== periodEnd) { this.periodEnd_ = periodEnd; } } if (shouldFit) { this.fitTimeline(); } } /** * Updates the init segment reference and propagates the update to all * references. * @param {shaka.media.InitSegmentReference} initSegmentReference */ updateInitSegmentReference(initSegmentReference) { if (this.initSegmentReference_ === initSegmentReference) { return; } this.initSegmentReference_ = initSegmentReference; for (const reference of this.references) { if (reference) { reference.updateInitSegmentReference(initSegmentReference); } } } /** * * @param {number} time */ isBeforeFirstEntry(time) { const hasTimeline = this.templateInfo_ && this.templateInfo_.timeline && this.templateInfo_.timeline.length; if (hasTimeline) { const timeline = this.templateInfo_.timeline; return time < timeline[0].start + this.periodStart_; } else { return false; } } /** * Fit timeline entries to period boundaries */ fitTimeline() { if (this.getIsImmutable()) { return; } const timeline = this.templateInfo_.timeline; while (timeline.length) { const lastTimePeriod = timeline[timeline.length - 1]; if (lastTimePeriod.start >= this.periodEnd_) { timeline.pop(); } else { break; } } this.evict(this.periodStart_); // Do NOT adjust last range to match period end! With high precision // timestamps several recalculations may give wrong results on less precise // platforms. To mitigate that, we're using cached |periodEnd_| value in // find/get() methods whenever possible. } /** * @override */ find(time) { shaka.log.debug(`Find ${time}`); if (this.isBeforeFirstEntry(time)) { return this.numEvicted_; } if (!this.templateInfo_) { return null; } const timeline = this.templateInfo_.timeline; // Early exit if the time isn't within this period if (time < this.periodStart_ || time >= this.periodEnd_) { return null; } const lastIndex = timeline.length - 1; for (let i = 0; i < timeline.length; i++) { const range = timeline[i]; const start = range.start + this.periodStart_; // A rounding error can cause /time/ to equal e.endTime or fall in between // the references by a fraction of a second. To account for this, we use // the start of the next segment as /end/, unless this is the last // reference, in which case we use the period end as the /end/ let end; if (i < lastIndex) { end = timeline[i + 1].start + this.periodStart_; } else if (this.periodEnd_ === Infinity) { end = range.end + this.periodStart_; } else { end = this.periodEnd_; } if ((time >= start) && (time < end)) { return i + this.numEvicted_; } } return null; } /** * @override */ get(position) { const correctedPosition = position - this.numEvicted_; if (correctedPosition < 0 || correctedPosition >= this.getNumReferences() || !this.templateInfo_) { return null; } let ref = this.references[correctedPosition]; if (!ref) { const mediaTemplate = this.templateInfo_.mediaTemplate; const range = this.templateInfo_.timeline[correctedPosition]; const segmentReplacement = range.segmentPosition; const timeReplacement = this.templateInfo_ .unscaledPresentationTimeOffset + range.unscaledStart; const timestampOffset = this.periodStart_ - this.templateInfo_.scaledPresentationTimeOffset; const trueSegmentEnd = this.periodStart_ + range.end; let segmentEnd = trueSegmentEnd; if (correctedPosition === this.getNumReferences() - 1 && this.periodEnd_ !== Infinity) { segmentEnd = this.periodEnd_; } const codecs = this.templateInfo_.codecs; const mimeType = this.templateInfo_.mimeType; const partialSegmentRefs = []; const partialDuration = (range.end - range.start) / range.partialSegments; for (let i = 0; i < range.partialSegments; i++) { const start = range.start + partialDuration * i; const end = start + partialDuration; const subNumber = i + 1; let uris = null; const getPartialUris = () => { if (!this.templateInfo_) { return []; } if (uris == null) { uris = shaka.dash.TimelineSegmentIndex.createUris_( this.templateInfo_.mediaTemplate, this.representationId_, segmentReplacement, this.bandwidth_, timeReplacement, subNumber, this.getBaseUris_); } return uris; }; const partial = new shaka.media.SegmentReference( this.periodStart_ + start, this.periodStart_ + end, getPartialUris, /* startByte= */ 0, /* endByte= */ null, this.initSegmentReference_, timestampOffset, this.periodStart_, this.periodEnd_, /* partialReferences= */ [], /* tilesLayout= */ '', /* tileDuration= */ null, /* syncTime= */ null, shaka.media.SegmentReference.Status.AVAILABLE, this.aesKey_); partial.codecs = codecs; partial.mimeType = mimeType; if (this.segmentSequenceCadence_ == 0) { if (i > 0) { partial.markAsNonIndependent(); } } else if ((i % this.segmentSequenceCadence_) != 0) { partial.markAsNonIndependent(); } partialSegmentRefs.push(partial); } const createUrisCb = () => { if (range.partialSegments > 0) { return []; } return shaka.dash.TimelineSegmentIndex .createUris_( mediaTemplate, this.representationId_, segmentReplacement, this.bandwidth_, timeReplacement, /* subNumber= */ null, this.getBaseUris_, ); }; ref = new shaka.media.SegmentReference( this.periodStart_ + range.start, segmentEnd, createUrisCb, /* startByte= */ 0, /* endByte= */ null, this.initSegmentReference_, timestampOffset, this.periodStart_, this.periodEnd_, partialSegmentRefs, /* tilesLayout= */ '', /* tileDuration= */ null, /* syncTime= */ null, shaka.media.SegmentReference.Status.AVAILABLE, this.aesKey_, /* allPartialSegments= */ range.partialSegments > 0); ref.codecs = codecs; ref.mimeType = mimeType; ref.trueEndTime = trueSegmentEnd; this.references[correctedPosition] = ref; } return ref; } /** * Fill in a specific template with values to get the segment uris * * @return {!Array.<string>} * @private */ static createUris_(mediaTemplate, repId, segmentReplacement, bandwidth, timeReplacement, subNumber, getBaseUris) { const mediaUri = shaka.dash.MpdUtils.fillUriTemplate( mediaTemplate, repId, segmentReplacement, subNumber, bandwidth || null, timeReplacement); return shaka.util.ManifestParserUtils .resolveUris(getBaseUris(), [mediaUri]) .map((g) => { return g.toString(); }); }};/** * @typedef {{ * timescale: number, * segmentDuration: ?number, * startNumber: number, * scaledPresentationTimeOffset: number, * unscaledPresentationTimeOffset: number, * timeline: Array.<shaka.media.PresentationTimeline.TimeRange>, * mediaTemplate: ?string, * indexTemplate: ?string, * mimeType: string, * codecs: string * }} * * @description * Contains information about a SegmentTemplate. * * @property {number} timescale * The time-scale of the representation. * @property {?number} segmentDuration * The duration of the segments in seconds, if given. * @property {number} startNumber * The start number of the segments; 1 or greater. * @property {number} scaledPresentationTimeOffset * The presentation time offset of the representation, in seconds. * @property {number} unscaledPresentationTimeOffset * The presentation time offset of the representation, in timescale units. * @property {Array.<shaka.media.PresentationTimeline.TimeRange>} timeline * The timeline of the representation, if given. Times in seconds. * @property {?string} mediaTemplate * The media URI template, if given. * @property {?string} indexTemplate * The index URI template, if given. * @property {string} mimeType * The mimeType. * @property {string} codecs * The codecs. */shaka.dash.SegmentTemplate.SegmentTemplateInfo;