shaka-player
Version:
DASH/EME video player library
914 lines (803 loc) • 31.5 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.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.aes128Key|undefined} aes128Key
* @return {shaka.dash.DashParser.StreamInfo}
*/
static createStreamInfo(
context, requestSegment, streamMap, isUpdate, segmentLimit,
periodDurationMap, aes128Key) {
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, aes128Key);
/** @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, aes128Key);
},
};
} 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.baseUris,
periodStart,
periodEnd,
initSegmentReference,
shouldFit,
aes128Key,
);
} else {
const tsi = /** @type {!TimelineSegmentIndex} */(segmentIndex);
tsi.appendTemplateInfo(info, periodStart, periodEnd, shouldFit);
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);
}
return Promise.resolve(segmentIndex);
},
};
}
}
/**
* @param {?shaka.dash.DashParser.InheritanceFrame} frame
* @return {Element}
* @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 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,
indexTemplate: index,
};
}
/**
* 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, context.bandwidth || null, null);
const resolvedUris = ManifestParserUtils.resolveUris(
context.representation.baseUris, [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.aes128Key|undefined} aes128Key
* @return {!Promise.<shaka.media.SegmentIndex>}
* @private
*/
static generateSegmentIndexFromDuration_(
context, info, segmentLimit, initSegmentReference, periodDurationMap,
aes128Key) {
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 baseUris = context.representation.baseUris;
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,
];
// 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 = 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, bandwidth, time);
return ManifestParserUtils.resolveUris(baseUris, [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,
aes128Key);
// 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);
segmentIndex.updateEvery(segmentDuration, () => {
// 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.aes128Key|undefined} aes128Key
* @return {shaka.media.InitSegmentReference}
* @private
*/
static createInitSegment_(context, aes128Key) {
const MpdUtils = shaka.dash.MpdUtils;
const ManifestParserUtils = shaka.util.ManifestParserUtils;
const SegmentTemplate = shaka.dash.SegmentTemplate;
const initialization = MpdUtils.inheritAttribute(
context, SegmentTemplate.fromInheritance_, 'initialization');
if (!initialization) {
return null;
}
const repId = context.representation.id;
const bandwidth = context.bandwidth || null;
const baseUris = context.representation.baseUris;
const getUris = () => {
goog.asserts.assert(initialization, 'Should have returned earler');
const filledTemplate = MpdUtils.fillUriTemplate(
initialization, repId, null, bandwidth, null);
const resolvedUris = ManifestParserUtils.resolveUris(
baseUris, [filledTemplate]);
return resolvedUris;
};
const qualityInfo = shaka.dash.SegmentBase.createQualityInfo(context);
return new shaka.media.InitSegmentReference(
getUris,
/* startByte= */ 0,
/* endByte= */ null,
qualityInfo,
/* timescale= */ null,
/* segmentData= */ null,
aes128Key);
}
};
/**
* 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 {Array.<string>} baseUris
* @param {number} periodStart
* @param {number} periodEnd
* @param {shaka.media.InitSegmentReference} initSegmentReference
* @param {boolean} shouldFit
* @param {shaka.extern.aes128Key|undefined} aes128Key
*/
constructor(templateInfo, representationId, bandwidth, baseUris,
periodStart, periodEnd, initSegmentReference, shouldFit,
aes128Key) {
super([]);
/** @private {?shaka.dash.SegmentTemplate.SegmentTemplateInfo} */
this.templateInfo_ = templateInfo;
/** @private {?string} */
this.representationId_ = representationId;
/** @private {number} */
this.bandwidth_ = bandwidth;
/** @private {Array.<string>} */
this.baseUris_ = baseUris;
/** @private {number} */
this.periodStart_ = periodStart;
/** @private {number} */
this.periodEnd_ = periodEnd;
/** @private {shaka.media.InitSegmentReference} */
this.initSegmentReference_ = initSegmentReference;
/** @private {shaka.extern.aes128Key|undefined} */
this.aes128Key_ = aes128Key;
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
*/
appendTemplateInfo(info, periodStart, periodEnd, shouldFit) {
if (!this.templateInfo_) {
this.templateInfo_ = info;
this.periodStart_ = periodStart;
this.periodEnd_ = periodEnd;
} else {
const currentTimeline = this.templateInfo_.timeline;
// 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();
}
}
/**
*
* @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_);
if (timeline.length === 0) {
return;
}
if (this.periodEnd_ !== Infinity) {
// Adjust the last timeline entry to match the period end
const lastTimePeriod = timeline[timeline.length - 1];
// NOTE: end should be relative to period start
lastTimePeriod.end = this.periodEnd_ - this.periodStart_;
}
}
/**
* @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 = range.end + this.periodStart_;
if (i < lastIndex) {
end = timeline[i + 1].start + this.periodStart_;
}
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 = position + this.templateInfo_.startNumber;
const timeReplacement = this.templateInfo_
.unscaledPresentationTimeOffset + range.unscaledStart;
const createUrisCb = () => {
if (!this.templateInfo_) {
return [];
}
return shaka.dash.TimelineSegmentIndex
.createUris_(
this.templateInfo_.mediaTemplate,
this.representationId_,
segmentReplacement,
this.bandwidth_,
timeReplacement,
this.baseUris_,
);
};
const timestampOffset = this.periodStart_ -
this.templateInfo_.scaledPresentationTimeOffset;
ref = new shaka.media.SegmentReference(
this.periodStart_ + range.start,
this.periodStart_ + range.end,
createUrisCb,
/* startByte= */ 0,
/* endByte= */ null,
this.initSegmentReference_,
timestampOffset,
this.periodStart_,
this.periodEnd_,
/* partialReferences= */ [],
/* tilesLayout= */ '',
/* tileDuration= */ null,
/* syncTime= */ null,
shaka.media.SegmentReference.Status.AVAILABLE,
this.aes128Key_);
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, baseUris) {
const mediaUri = shaka.dash.MpdUtils.fillUriTemplate(
mediaTemplate, repId,
segmentReplacement, bandwidth || null, timeReplacement);
return shaka.util.ManifestParserUtils
.resolveUris(baseUris, [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
* }}
*
* @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.
*/
shaka.dash.SegmentTemplate.SegmentTemplateInfo;