shaka-player
Version:
DASH/EME video player library
1,220 lines (1,080 loc) • 42.2 kB
JavaScript
/*! @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.require('shaka.util.TXml');
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 {!Map<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 {!Map<string, number>} periodDurationMap
* @param {shaka.extern.aesKey|undefined} aesKey
* @param {?number} lastSegmentNumber
* @param {boolean} isPatchUpdate
* @return {shaka.dash.DashParser.StreamInfo}
*/
static createStreamInfo(
context, requestSegment, streamMap, isUpdate, segmentLimit,
periodDurationMap, aesKey, lastSegmentNumber, isPatchUpdate) {
goog.asserts.assert(context.representation.segmentTemplate,
'Should only be called with SegmentTemplate ' +
'or segment info defined');
const MpdUtils = shaka.dash.MpdUtils;
const SegmentTemplate = shaka.dash.SegmentTemplate;
const TimelineSegmentIndex = shaka.dash.TimelineSegmentIndex;
if (!isPatchUpdate && !context.representation.initialization) {
context.representation.initialization =
MpdUtils.inheritAttribute(
context, SegmentTemplate.fromInheritance_, 'initialization');
}
const initSegmentReference = context.representation.initialization ?
SegmentTemplate.createInitSegment_(context, aesKey) : null;
/** @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.adaptationSet.contentType !== 'text') {
const periodStart = context.periodInfo.start;
const periodId = context.period.id;
const initialPeriodDuration = context.periodInfo.duration;
const periodDuration =
(periodId != null && periodDurationMap.get(periodId)) ||
initialPeriodDuration;
const periodEnd = periodDuration ?
(periodStart + periodDuration) : Infinity;
context.presentationTimeline.notifyMaxSegmentDuration(
info.segmentDuration);
context.presentationTimeline.notifyPeriodDuration(
periodStart, periodEnd);
}
return {
generateSegmentIndex: () => {
return SegmentTemplate.generateSegmentIndexFromDuration_(
shallowCopyOfContext, info, segmentLimit, initSegmentReference,
periodDurationMap, aesKey, lastSegmentNumber,
context.representation.segmentSequenceCadence);
},
};
} 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.get(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}`);
if (!segmentIndex) {
shaka.log.debug(`Creating TSI with end ${periodEnd}`);
segmentIndex = new TimelineSegmentIndex(
info,
context.representation.originalId,
context.bandwidth,
context.representation.getBaseUris,
context.urlParams,
periodStart,
periodEnd,
initSegmentReference,
aesKey,
context.representation.segmentSequenceCadence,
);
} else {
const tsi = /** @type {!TimelineSegmentIndex} */(segmentIndex);
tsi.appendTemplateInfo(
info, periodStart, periodEnd, initSegmentReference);
const availabilityStart =
context.presentationTimeline.getSegmentAvailabilityStart();
tsi.evict(availabilityStart);
}
if (info.timeline &&
context.adaptationSet.contentType !== 'image' &&
context.adaptationSet.contentType !== 'text') {
const tsi = /** @type {!TimelineSegmentIndex} */(segmentIndex);
// getTimeline is the info.timeline but fitted to the period.
const timeline = tsi.getTimeline();
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, initSegmentReference);
}
return Promise.resolve(segmentIndex);
},
};
}
}
/**
* Ingests Patch MPD segments into timeline.
*
* @param {!shaka.dash.DashParser.Context} context
* @param {shaka.extern.xml.Node} patchNode
*/
static modifyTimepoints(context, patchNode) {
const MpdUtils = shaka.dash.MpdUtils;
const SegmentTemplate = shaka.dash.SegmentTemplate;
const TXml = shaka.util.TXml;
const timelineNode = MpdUtils.inheritChild(context,
SegmentTemplate.fromInheritance_, 'SegmentTimeline');
goog.asserts.assert(timelineNode, 'timeline node not found');
const timepoints = TXml.findChildren(timelineNode, 'S');
goog.asserts.assert(timepoints, 'timepoints should exist');
TXml.modifyNodes(timepoints, patchNode);
timelineNode.children = timepoints;
}
/**
* Removes all segments from timeline.
*
* @param {!shaka.dash.DashParser.Context} context
*/
static removeTimepoints(context) {
const MpdUtils = shaka.dash.MpdUtils;
const SegmentTemplate = shaka.dash.SegmentTemplate;
const timelineNode = MpdUtils.inheritChild(context,
SegmentTemplate.fromInheritance_, 'SegmentTimeline');
goog.asserts.assert(timelineNode, 'timeline node not found');
timelineNode.children = [];
}
/**
* @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');
const k = MpdUtils.inheritAttribute(
context, SegmentTemplate.fromInheritance_, 'k');
let numChunks = 0;
if (k) {
numChunks = parseInt(k, 10);
}
return {
unscaledSegmentDuration: segmentInfo.unscaledSegmentDuration,
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,
bandwidth: context.bandwidth,
numChunks: numChunks,
};
}
/**
* 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 contains 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.unscaledSegmentDuration = null;
info.segmentDuration = null;
} else {
goog.asserts.assert(info.timeline, 'There should be a timeline');
shaka.log.info('Using the SegmentTimeline by default.');
info.unscaledSegmentDuration = null;
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.originalId,
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 {!Map<string, number>} periodDurationMap
* @param {shaka.extern.aesKey|undefined} aesKey
* @param {?number} lastSegmentNumber
* @param {number} segmentSequenceCadence
* @return {!Promise<shaka.media.SegmentIndex>}
* @private
*/
static generateSegmentIndexFromDuration_(
context, info, segmentLimit, initSegmentReference, periodDurationMap,
aesKey, lastSegmentNumber, segmentSequenceCadence) {
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.get(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 template = info.mediaTemplate;
const bandwidth = context.bandwidth || null;
const id = context.representation.id;
const getBaseUris = context.representation.getBaseUris;
const urlParams = context.urlParams;
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;
const unscaledSegmentDuration = info.unscaledSegmentDuration;
goog.asserts.assert(unscaledSegmentDuration != null,
'Segment duration must not be null!');
// The original media timestamp from the timeline is what is expected in
// the $Time$ template. (Or based on duration, in this case.) It should
// not be adjusted with presentationTimeOffset or the Period start.
let timeReplacement = positionWithinPeriod * unscaledSegmentDuration;
if ('BigInt' in window && timeReplacement > Number.MAX_SAFE_INTEGER) {
timeReplacement =
BigInt(positionWithinPeriod) * BigInt(unscaledSegmentDuration);
}
// 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 partialSegmentRefs = [];
const numChunks = info.numChunks;
if (numChunks) {
const partialDuration = (segmentEnd - segmentStart) / numChunks;
for (let i = 0; i < numChunks; i++) {
const start = segmentStart + partialDuration * i;
const end = start + partialDuration;
const subNumber = i + 1;
const getPartialUris = () => {
const mediaUri = MpdUtils.fillUriTemplate(
template, id, position, subNumber, bandwidth, timeReplacement);
return ManifestParserUtils.resolveUris(
getBaseUris(), [mediaUri], urlParams());
};
const partial = new shaka.media.SegmentReference(
start,
end,
getPartialUris,
/* startByte= */ 0,
/* endByte= */ null,
initSegmentReference,
timestampOffset,
/* appendWindowStart= */ periodStart,
/* appendWindowEnd= */ getPeriodEnd(),
/* partialReferences= */ [],
/* tilesLayout= */ '',
/* tileDuration= */ null,
/* syncTime= */ null,
shaka.media.SegmentReference.Status.AVAILABLE,
aesKey);
partial.codecs = context.representation.codecs;
partial.mimeType = context.representation.mimeType;
if (segmentSequenceCadence == 0) {
if (i > 0) {
partial.markAsNonIndependent();
}
} else if ((i % segmentSequenceCadence) != 0) {
partial.markAsNonIndependent();
}
partialSegmentRefs.push(partial);
}
}
const getUris = () => {
if (numChunks) {
return [];
}
const mediaUri = MpdUtils.fillUriTemplate(
template, id, position, /* subNumber= */ null, bandwidth,
timeReplacement);
return ManifestParserUtils.resolveUris(
getBaseUris(), [mediaUri], urlParams());
};
const ref = new shaka.media.SegmentReference(
segmentStart,
segmentEnd,
getUris,
/* startByte= */ 0,
/* endByte= */ null,
initSegmentReference,
timestampOffset,
/* appendWindowStart= */ periodStart,
/* appendWindowEnd= */ getPeriodEnd(),
partialSegmentRefs,
/* tilesLayout= */ '',
/* tileDuration= */ null,
/* syncTime= */ null,
shaka.media.SegmentReference.Status.AVAILABLE,
aesKey,
partialSegmentRefs.length > 0);
ref.codecs = context.representation.codecs;
ref.mimeType = context.representation.mimeType;
ref.bandwidth = context.bandwidth;
// 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 = context.representation.initialization;
if (!initialization) {
initialization = MpdUtils.inheritAttribute(
context, SegmentTemplate.fromInheritance_, 'initialization');
}
if (!initialization) {
return null;
}
initialization = shaka.util.StringUtils.htmlUnescape(initialization);
const repId = context.representation.originalId;
const bandwidth = context.bandwidth || null;
const getBaseUris = context.representation.getBaseUris;
const urlParams = context.urlParams;
const getUris = () => {
goog.asserts.assert(initialization, 'Should have returned earlier');
const filledTemplate = MpdUtils.fillUriTemplate(
initialization, repId, null, null, bandwidth, null);
const resolvedUris = ManifestParserUtils.resolveUris(
getBaseUris(), [filledTemplate], urlParams());
return resolvedUris;
};
const qualityInfo = shaka.dash.SegmentBase.createQualityInfo(context);
const encrypted = context.adaptationSet.encrypted;
const ref = new shaka.media.InitSegmentReference(
getUris,
/* startByte= */ 0,
/* endByte= */ null,
qualityInfo,
/* timescale= */ null,
/* segmentData= */ null,
aesKey,
encrypted);
ref.codecs = context.representation.codecs;
ref.mimeType = context.representation.mimeType;
if (context.periodInfo) {
ref.boundaryEnd = context.periodInfo.start + context.periodInfo.duration;
}
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 {function():string} urlParams
* @param {number} periodStart
* @param {number} periodEnd
* @param {shaka.media.InitSegmentReference} initSegmentReference
* @param {shaka.extern.aesKey|undefined} aesKey
* @param {number} segmentSequenceCadence
*/
constructor(templateInfo, representationId, bandwidth, getBaseUris,
urlParams, periodStart, periodEnd, initSegmentReference,
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 {function():string} */
this.urlParams_ = urlParams;
/** @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;
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 {shaka.media.InitSegmentReference} initSegmentReference
*/
appendTemplateInfo(info, periodStart, periodEnd, initSegmentReference) {
this.updateInitSegmentReference(initSegmentReference);
if (!this.templateInfo_) {
this.templateInfo_ = info;
this.periodStart_ = periodStart;
this.periodEnd_ = periodEnd;
} else {
const currentTimeline = this.templateInfo_.timeline;
if (this.templateInfo_.mediaTemplate !== info.mediaTemplate) {
this.templateInfo_.mediaTemplate = info.mediaTemplate;
}
// Append timeline
let newEntries;
if (currentTimeline.length) {
const lastCurrentEntry = currentTimeline[currentTimeline.length - 1];
newEntries = info.timeline.filter((entry) => {
return entry.end > lastCurrentEntry.end;
});
} else {
newEntries = info.timeline.slice();
}
if (newEntries.length > 0) {
shaka.log.debug(`Appending ${newEntries.length} entries`);
this.templateInfo_.timeline.push(...newEntries);
}
if (this.periodEnd_ !== periodEnd) {
this.periodEnd_ = periodEnd;
}
}
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.templateInfo_ || this.getIsImmutable()) {
return;
}
const timeline = this.templateInfo_.timeline;
goog.asserts.assert(timeline, 'Timeline should be non-null!');
const newTimeline = [];
for (const range of timeline) {
if (range.start >= this.periodEnd_) {
// Starts after end of period.
} else if (range.end <= 0) {
// Ends before start of period.
} else {
// Usable.
newTimeline.push(range);
}
}
this.templateInfo_.timeline = newTimeline;
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.
}
/**
* Get the current timeline
* @return {!Array<shaka.media.PresentationTimeline.TimeRange>}
*/
getTimeline() {
if (!this.templateInfo_) {
return [];
}
const timeline = this.templateInfo_.timeline;
goog.asserts.assert(timeline, 'Timeline should be non-null!');
return timeline;
}
/**
* @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 range = this.templateInfo_.timeline[correctedPosition];
const segmentReplacement = range.segmentPosition;
// The original media timestamp from the timeline is what is expected in
// the $Time$ template. It should not be adjusted with
// presentationTimeOffset or the Period start, but
// unscaledPresentationTimeOffset was already subtracted from the times
// in timeline.
const timeReplacement = range.unscaledStart +
this.templateInfo_.unscaledPresentationTimeOffset;
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 bandwidth = this.templateInfo_.bandwidth;
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_,
this.urlParams_);
}
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;
partial.bandwidth = bandwidth;
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 || !this.templateInfo_) {
return [];
}
return shaka.dash.TimelineSegmentIndex
.createUris_(
this.templateInfo_.mediaTemplate,
this.representationId_,
segmentReplacement,
this.bandwidth_,
timeReplacement,
/* subNumber= */ null,
this.getBaseUris_,
this.urlParams_,
);
};
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;
ref.bandwidth = bandwidth;
this.references[correctedPosition] = ref;
}
return ref;
}
/**
* @override
*/
forEachTopLevelReference(fn) {
this.fitTimeline();
for (let i = 0; i < this.getNumReferences(); i++) {
const reference = this.get(i + this.numEvicted_);
if (reference) {
fn(reference);
}
}
}
/**
* 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, urlParams) {
const mediaUri = shaka.dash.MpdUtils.fillUriTemplate(
mediaTemplate, repId,
segmentReplacement, subNumber, bandwidth || null, timeReplacement);
return shaka.util.ManifestParserUtils
.resolveUris(getBaseUris(), [mediaUri], urlParams())
.map((g) => {
return g.toString();
});
}
};
/**
* @typedef {{
* timescale: number,
* unscaledSegmentDuration: ?number,
* segmentDuration: ?number,
* startNumber: number,
* scaledPresentationTimeOffset: number,
* unscaledPresentationTimeOffset: number,
* timeline: Array<shaka.media.PresentationTimeline.TimeRange>,
* mediaTemplate: ?string,
* indexTemplate: ?string,
* mimeType: string,
* codecs: string,
* bandwidth: number,
* numChunks: number
* }}
*
* @description
* Contains information about a SegmentTemplate.
*
* @property {number} timescale
* The time-scale of the representation.
* @property {?number} unscaledSegmentDuration
* The duration of the segments in seconds, in timescale units.
* @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.
* @property {number} bandwidth
* The bandwidth.
* @property {number} numChunks
* The number of chunks in each segment.
*/
shaka.dash.SegmentTemplate.SegmentTemplateInfo;