mirror of
https://github.com/shaka-project/shaka-player.git
synced 2026-06-25 17:45:03 +03:00
ismena
7e50866bb5
In live streams, we can evict segments outside the availability window faster than they disappear from the manifest. If that happens, we used to evict them several times (add them back in and then evict again). This caused the eviction counter to increase beyond what it should be and we had trouble finding segments afterwards. Closes #3139. Change-Id: Iafebfaf8e1e9ebb09a64cdf7e09a882115fd8eb6
340 lines
12 KiB
JavaScript
340 lines
12 KiB
JavaScript
/*! @license
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* Shaka Player
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* Copyright 2016 Google LLC
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* SPDX-License-Identifier: Apache-2.0
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*/
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goog.provide('shaka.dash.SegmentList');
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goog.require('goog.asserts');
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goog.require('shaka.dash.MpdUtils');
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goog.require('shaka.dash.SegmentBase');
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goog.require('shaka.log');
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goog.require('shaka.media.InitSegmentReference');
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goog.require('shaka.media.SegmentIndex');
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goog.require('shaka.media.SegmentReference');
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goog.require('shaka.util.Error');
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goog.require('shaka.util.Functional');
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goog.require('shaka.util.Iterables');
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goog.require('shaka.util.ManifestParserUtils');
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goog.require('shaka.util.XmlUtils');
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goog.requireType('shaka.dash.DashParser');
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/**
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* @summary A set of functions for parsing SegmentList elements.
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*/
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shaka.dash.SegmentList = class {
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/**
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* Creates a new StreamInfo object.
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* Updates the existing SegmentIndex, if any.
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*
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* @param {shaka.dash.DashParser.Context} context
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* @param {!Object.<string, !shaka.media.SegmentIndex>} segmentIndexMap
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* @return {shaka.dash.DashParser.StreamInfo}
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*/
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static createStreamInfo(context, segmentIndexMap) {
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goog.asserts.assert(context.representation.segmentList,
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'Should only be called with SegmentList');
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const SegmentList = shaka.dash.SegmentList;
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const initSegmentReference = shaka.dash.SegmentBase.createInitSegment(
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context, SegmentList.fromInheritance_);
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const info = SegmentList.parseSegmentListInfo_(context);
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SegmentList.checkSegmentListInfo_(context, info);
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/** @type {shaka.media.SegmentIndex} */
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let segmentIndex = null;
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let id = null;
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if (context.period.id && context.representation.id) {
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// Only check/store the index if period and representation IDs are set.
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id = context.period.id + ',' + context.representation.id;
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segmentIndex = segmentIndexMap[id];
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}
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const references = SegmentList.createSegmentReferences_(
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context.periodInfo.start, context.periodInfo.duration,
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info.startNumber, context.representation.baseUris, info,
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initSegmentReference);
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const isNew = !segmentIndex;
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if (segmentIndex) {
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const start = context.presentationTimeline.getSegmentAvailabilityStart();
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segmentIndex.mergeAndEvict(references, start);
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} else {
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context.presentationTimeline.notifySegments(references);
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segmentIndex = new shaka.media.SegmentIndex(references);
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if (id && context.dynamic) {
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segmentIndexMap[id] = segmentIndex;
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}
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}
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if (!context.dynamic || !context.periodInfo.isLastPeriod) {
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const periodStart = context.periodInfo.start;
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const periodEnd = context.periodInfo.duration ?
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context.periodInfo.start + context.periodInfo.duration : Infinity;
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segmentIndex.fit(periodStart, periodEnd, isNew);
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}
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return {
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generateSegmentIndex: () => Promise.resolve(segmentIndex),
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};
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}
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/**
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* @param {?shaka.dash.DashParser.InheritanceFrame} frame
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* @return {Element}
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* @private
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*/
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static fromInheritance_(frame) {
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return frame.segmentList;
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}
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/**
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* Parses the SegmentList items to create an info object.
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*
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* @param {shaka.dash.DashParser.Context} context
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* @return {shaka.dash.SegmentList.SegmentListInfo}
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* @private
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*/
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static parseSegmentListInfo_(context) {
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const SegmentList = shaka.dash.SegmentList;
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const MpdUtils = shaka.dash.MpdUtils;
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const mediaSegments = SegmentList.parseMediaSegments_(context);
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const segmentInfo =
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MpdUtils.parseSegmentInfo(context, SegmentList.fromInheritance_);
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let startNumber = segmentInfo.startNumber;
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if (startNumber == 0) {
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shaka.log.warning('SegmentList@startNumber must be > 0');
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startNumber = 1;
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}
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let startTime = 0;
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if (segmentInfo.segmentDuration) {
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// See DASH sec. 5.3.9.5.3
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// Don't use presentationTimeOffset for @duration.
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startTime = segmentInfo.segmentDuration * (startNumber - 1);
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} else if (segmentInfo.timeline && segmentInfo.timeline.length > 0) {
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// The presentationTimeOffset was considered in timeline creation.
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startTime = segmentInfo.timeline[0].start;
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}
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return {
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segmentDuration: segmentInfo.segmentDuration,
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startTime: startTime,
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startNumber: startNumber,
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scaledPresentationTimeOffset: segmentInfo.scaledPresentationTimeOffset,
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timeline: segmentInfo.timeline,
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mediaSegments: mediaSegments,
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};
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}
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/**
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* Checks whether a SegmentListInfo object is valid.
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*
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* @param {shaka.dash.DashParser.Context} context
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* @param {shaka.dash.SegmentList.SegmentListInfo} info
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* @private
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*/
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static checkSegmentListInfo_(context, info) {
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if (!info.segmentDuration && !info.timeline &&
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info.mediaSegments.length > 1) {
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shaka.log.warning(
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'SegmentList does not contain sufficient segment information:',
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'the SegmentList specifies multiple segments,',
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'but does not specify a segment duration or timeline.',
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context.representation);
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throw new shaka.util.Error(
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shaka.util.Error.Severity.CRITICAL,
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shaka.util.Error.Category.MANIFEST,
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shaka.util.Error.Code.DASH_NO_SEGMENT_INFO);
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}
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if (!info.segmentDuration && !context.periodInfo.duration &&
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!info.timeline && info.mediaSegments.length == 1) {
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shaka.log.warning(
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'SegmentList does not contain sufficient segment information:',
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'the SegmentList specifies one segment,',
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'but does not specify a segment duration, period duration,',
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'or timeline.',
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context.representation);
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throw new shaka.util.Error(
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shaka.util.Error.Severity.CRITICAL,
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shaka.util.Error.Category.MANIFEST,
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shaka.util.Error.Code.DASH_NO_SEGMENT_INFO);
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}
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if (info.timeline && info.timeline.length == 0) {
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shaka.log.warning(
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'SegmentList does not contain sufficient segment information:',
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'the SegmentList has an empty timeline.',
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context.representation);
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throw new shaka.util.Error(
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shaka.util.Error.Severity.CRITICAL,
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shaka.util.Error.Category.MANIFEST,
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shaka.util.Error.Code.DASH_NO_SEGMENT_INFO);
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}
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}
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/**
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* Creates an array of segment references for the given data.
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*
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* @param {number} periodStart in seconds.
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* @param {?number} periodDuration in seconds.
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* @param {number} startNumber
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* @param {!Array.<string>} baseUris
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* @param {shaka.dash.SegmentList.SegmentListInfo} info
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* @param {shaka.media.InitSegmentReference} initSegmentReference
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* @return {!Array.<!shaka.media.SegmentReference>}
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* @private
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*/
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static createSegmentReferences_(
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periodStart, periodDuration, startNumber, baseUris, info,
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initSegmentReference) {
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const ManifestParserUtils = shaka.util.ManifestParserUtils;
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let max = info.mediaSegments.length;
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if (info.timeline && info.timeline.length != info.mediaSegments.length) {
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max = Math.min(info.timeline.length, info.mediaSegments.length);
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shaka.log.warning(
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'The number of items in the segment timeline and the number of ',
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'segment URLs do not match, truncating', info.mediaSegments.length,
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'to', max);
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}
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const timestampOffset = periodStart - info.scaledPresentationTimeOffset;
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const appendWindowStart = periodStart;
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const appendWindowEnd = periodDuration ?
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periodStart + periodDuration : Infinity;
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/** @type {!Array.<!shaka.media.SegmentReference>} */
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const references = [];
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let prevEndTime = info.startTime;
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for (const i of shaka.util.Iterables.range(max)) {
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const segment = info.mediaSegments[i];
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const mediaUri = ManifestParserUtils.resolveUris(
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baseUris, [segment.mediaUri]);
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const startTime = prevEndTime;
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let endTime;
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if (info.segmentDuration != null) {
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endTime = startTime + info.segmentDuration;
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} else if (info.timeline) {
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// Ignore the timepoint start since they are continuous.
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endTime = info.timeline[i].end;
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} else {
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// If segmentDuration and timeline are null then there must
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// be exactly one segment.
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goog.asserts.assert(
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info.mediaSegments.length == 1 && periodDuration,
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'There should be exactly one segment with a Period duration.');
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endTime = startTime + periodDuration;
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}
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const getUris = () => mediaUri;
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references.push(
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new shaka.media.SegmentReference(
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periodStart + startTime,
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periodStart + endTime,
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getUris,
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segment.start,
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segment.end,
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initSegmentReference,
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timestampOffset,
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appendWindowStart, appendWindowEnd));
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prevEndTime = endTime;
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}
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return references;
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}
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/**
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* Parses the media URIs from the context.
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*
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* @param {shaka.dash.DashParser.Context} context
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* @return {!Array.<shaka.dash.SegmentList.MediaSegment>}
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* @private
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*/
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static parseMediaSegments_(context) {
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const Functional = shaka.util.Functional;
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/** @type {!Array.<!Element>} */
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const segmentLists = [
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context.representation.segmentList,
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context.adaptationSet.segmentList,
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context.period.segmentList,
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].filter(Functional.isNotNull);
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const XmlUtils = shaka.util.XmlUtils;
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// Search each SegmentList for one with at least one SegmentURL element,
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// select the first one, and convert each SegmentURL element to a tuple.
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return segmentLists
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.map((node) => { return XmlUtils.findChildren(node, 'SegmentURL'); })
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.reduce((all, part) => { return all.length > 0 ? all : part; })
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.map((urlNode) => {
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if (urlNode.getAttribute('indexRange') &&
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!context.indexRangeWarningGiven) {
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context.indexRangeWarningGiven = true;
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shaka.log.warning(
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'We do not support the SegmentURL@indexRange attribute on ' +
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'SegmentList. We only use the SegmentList@duration ' +
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'attribute or SegmentTimeline, which must be accurate.');
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}
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const uri = urlNode.getAttribute('media');
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const range = XmlUtils.parseAttr(
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urlNode, 'mediaRange', XmlUtils.parseRange,
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{start: 0, end: null});
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return {mediaUri: uri, start: range.start, end: range.end};
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});
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}
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};
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/**
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* @typedef {{
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* mediaUri: string,
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* start: number,
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* end: ?number
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* }}
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*
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* @property {string} mediaUri
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* The URI of the segment.
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* @property {number} start
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* The start byte of the segment.
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* @property {?number} end
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* The end byte of the segment, or null.
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*/
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shaka.dash.SegmentList.MediaSegment;
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/**
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* @typedef {{
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* segmentDuration: ?number,
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* startTime: number,
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* startNumber: number,
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* scaledPresentationTimeOffset: number,
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* timeline: Array.<shaka.dash.MpdUtils.TimeRange>,
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* mediaSegments: !Array.<shaka.dash.SegmentList.MediaSegment>
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* }}
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* @private
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*
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* @description
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* Contains information about a SegmentList.
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*
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* @property {?number} segmentDuration
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* The duration of the segments, if given.
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* @property {number} startTime
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* The start time of the first segment, in seconds.
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* @property {number} startNumber
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* The start number of the segments; 1 or greater.
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* @property {number} scaledPresentationTimeOffset
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* The scaledPresentationTimeOffset of the representation, in seconds.
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* @property {Array.<shaka.dash.MpdUtils.TimeRange>} timeline
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* The timeline of the representation, if given. Times in seconds.
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* @property {!Array.<shaka.dash.SegmentList.MediaSegment>} mediaSegments
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* The URI and byte-ranges of the media segments.
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*/
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shaka.dash.SegmentList.SegmentListInfo;
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