/**
* @license
* Copyright 2016 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
goog.provide('shaka.dash.SegmentList');
goog.require('goog.asserts');
goog.require('shaka.dash.MpdUtils');
goog.require('shaka.dash.SegmentBase');
goog.require('shaka.media.SegmentIndex');
goog.require('shaka.media.SegmentReference');
goog.require('shaka.util.Error');
goog.require('shaka.util.Functional');
goog.require('shaka.util.XmlUtils');
/**
* @namespace shaka.dash.SegmentList
* @summary A set of functions for parsing SegmentList elements.
*/
/**
* Creates a new Stream object or updates the Stream in the manifest.
*
* @param {shaka.dash.DashParser.Context} context
* @param {!Object.<string, !shaka.media.SegmentIndex>} segmentIndexMap
* @return {shaka.dash.DashParser.StreamInfo}
*/
shaka.dash.SegmentList.createStream = function(context, segmentIndexMap) {
goog.asserts.assert(context.representation.segmentList,
'Should only be called with SegmentList');
var SegmentList = shaka.dash.SegmentList;
var init = shaka.dash.SegmentBase.createInitSegment(
context, SegmentList.fromInheritance_);
var info = SegmentList.parseSegmentListInfo_(context);
SegmentList.checkSegmentListInfo_(context, info);
/** @type {shaka.media.SegmentIndex} */
var segmentIndex = null;
var id = 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;
segmentIndex = segmentIndexMap[id];
}
var references = SegmentList.createSegmentReferences_(
context.periodInfo.start, context.periodInfo.duration, info.startNumber,
context.representation.baseUris, info);
shaka.dash.MpdUtils.fitSegmentReferences(
context.periodInfo.duration, references);
if (segmentIndex) {
segmentIndex.merge(references);
segmentIndex.evict(
context.presentationTimeline.getSegmentAvailabilityStart());
} else {
context.presentationTimeline.notifySegments(
context.periodInfo.start, references);
segmentIndex = new shaka.media.SegmentIndex(references);
if (id)
segmentIndexMap[id] = segmentIndex;
}
return {
createSegmentIndex: Promise.resolve.bind(Promise),
findSegmentPosition: segmentIndex.find.bind(segmentIndex),
getSegmentReference: segmentIndex.get.bind(segmentIndex),
initSegmentReference: init,
presentationTimeOffset: info.presentationTimeOffset
};
};
/**
* @typedef {{
* mediaUri: string,
* start: number,
* end: ?number
* }}
*
* @property {string} mediaUri
* The URI of the segment.
* @property {number} start
* The start byte of the segment.
* @property {?number} end
* The end byte of the segment, or null.
*/
shaka.dash.SegmentList.MediaSegment;
/**
* @typedef {{
* segmentDuration: ?number,
* startTime: number,
* startNumber: number,
* presentationTimeOffset: number,
* timeline: Array.<shaka.dash.MpdUtils.TimeRange>,
* mediaSegments: !Array.<shaka.dash.SegmentList.MediaSegment>
* }}
* @private
*
* @description
* Contains information about a SegmentList.
*
* @property {?number} segmentDuration
* The duration of the segments, if given.
* @property {number} startTime
* The start time of the first segment, in seconds.
* @property {number} startNumber
* The start number of the segments; 1 or greater.
* @property {number} presentationTimeOffset
* The presentationTimeOffset of the representation, in seconds.
* @property {Array.<shaka.dash.MpdUtils.TimeRange>} timeline
* The timeline of the representation, if given. Times in seconds.
* @property {!Array.<shaka.dash.SegmentList.MediaSegment>} mediaSegments
* The URI and byte-ranges of the media segments.
*/
shaka.dash.SegmentList.SegmentListInfo;
/**
* @param {?shaka.dash.DashParser.InheritanceFrame} frame
* @return {Element}
* @private
*/
shaka.dash.SegmentList.fromInheritance_ = function(frame) {
return frame.segmentList;
};
/**
* Parses the SegmentList items to create an info object.
*
* @param {shaka.dash.DashParser.Context} context
* @return {shaka.dash.SegmentList.SegmentListInfo}
* @private
*/
shaka.dash.SegmentList.parseSegmentListInfo_ = function(context) {
var SegmentList = shaka.dash.SegmentList;
var MpdUtils = shaka.dash.MpdUtils;
var mediaSegments = SegmentList.parseMediaSegments_(context);
var segmentInfo =
MpdUtils.parseSegmentInfo(context, SegmentList.fromInheritance_);
var startNumber = segmentInfo.startNumber;
if (startNumber === 0) {
shaka.log.warning('SegmentList@startNumber must be > 0');
startNumber = 1;
}
var startTime = 0;
if (segmentInfo.segmentDuration) {
// Consider the presentationTimeOffset
startTime = segmentInfo.segmentDuration * (startNumber - 1) -
segmentInfo.presentationTimeOffset;
} else if (segmentInfo.timeline && segmentInfo.timeline.length > 0) {
// The presentationTimeOffset was considered in timeline creation
startTime = segmentInfo.timeline[0].start;
}
return {
segmentDuration: segmentInfo.segmentDuration,
startTime: startTime,
startNumber: startNumber,
presentationTimeOffset: segmentInfo.presentationTimeOffset,
timeline: segmentInfo.timeline,
mediaSegments: mediaSegments
};
};
/**
* Checks whether a SegmentListInfo object is valid.
*
* @param {shaka.dash.DashParser.Context} context
* @param {shaka.dash.SegmentList.SegmentListInfo} info
* @throws shaka.util.Error When there is a parsing error.
* @private
*/
shaka.dash.SegmentList.checkSegmentListInfo_ = function(context, info) {
if (!info.segmentDuration && !info.timeline &&
info.mediaSegments.length > 1) {
shaka.log.warning(
'SegmentList does not contain sufficient segment information:',
'the SegmentList specifies multiple segments,',
'but does not specify a segment duration or timeline.',
context.representation);
throw new shaka.util.Error(
shaka.util.Error.Category.MANIFEST,
shaka.util.Error.Code.DASH_NO_SEGMENT_INFO);
}
if (!info.segmentDuration && !context.periodInfo.duration && !info.timeline &&
info.mediaSegments.length == 1) {
shaka.log.warning(
'SegmentList does not contain sufficient segment information:',
'the SegmentList specifies one segment,',
'but does not specify a segment duration, period duration,',
'or timeline.',
context.representation);
throw new shaka.util.Error(
shaka.util.Error.Category.MANIFEST,
shaka.util.Error.Code.DASH_NO_SEGMENT_INFO);
}
if (info.timeline && info.timeline.length == 0) {
shaka.log.warning(
'SegmentList does not contain sufficient segment information:',
'the SegmentList has an empty timeline.',
context.representation);
throw new shaka.util.Error(
shaka.util.Error.Category.MANIFEST,
shaka.util.Error.Code.DASH_NO_SEGMENT_INFO);
}
};
/**
* Creates an array of segment references for the given data.
*
* @param {number} periodStart in seconds.
* @param {?number} periodDuration in seconds.
* @param {number} startNumber
* @param {!Array.<string>} baseUris
* @param {shaka.dash.SegmentList.SegmentListInfo} info
* @return {!Array.<!shaka.media.SegmentReference>}
* @private
*/
shaka.dash.SegmentList.createSegmentReferences_ = function(
periodStart, periodDuration, startNumber, baseUris, info) {
var MpdUtils = shaka.dash.MpdUtils;
var max = info.mediaSegments.length;
if (info.timeline && info.timeline.length != info.mediaSegments.length) {
max = Math.min(info.timeline.length, info.mediaSegments.length);
shaka.log.warning(
'The number of items in the segment timeline and the number of segment',
'URLs do not match, truncating', info.mediaSegments.length, 'to', max);
}
/** @type {!Array.<!shaka.media.SegmentReference>} */
var references = [];
var prevEndTime = info.startTime;
for (var i = 0; i < max; i++) {
var segment = info.mediaSegments[i];
var mediaUri = MpdUtils.resolveUris(baseUris, [segment.mediaUri]);
var startTime = prevEndTime;
var endTime;
if (info.segmentDuration != null) {
endTime = startTime + info.segmentDuration;
} else if (info.timeline) {
// Ignore the timepoint start since they are continuous.
endTime = info.timeline[i].end;
} else {
// If segmentDuration and timeline are null then there must
// only be one segment.
goog.asserts.assert(
info.mediaSegments.length == 1 && periodDuration,
'There should only be one segment with a Period duration.');
endTime = startTime + periodDuration;
}
references.push(
new shaka.media.SegmentReference(
i + startNumber, startTime, endTime, mediaUri, segment.start,
segment.end));
prevEndTime = endTime;
}
return references;
};
/**
* Parses the media URIs from the context.
*
* @param {shaka.dash.DashParser.Context} context
* @return {!Array.<shaka.dash.SegmentList.MediaSegment>}
* @private
*/
shaka.dash.SegmentList.parseMediaSegments_ = function(context) {
var Functional = shaka.util.Functional;
/** @type {!Array.<!Element>} */
var segmentLists = [
context.representation.segmentList,
context.adaptationSet.segmentList,
context.period.segmentList
].filter(Functional.isNotNull);
var XmlUtils = shaka.util.XmlUtils;
// Search each SegmentList for one with at least one SegmentURL element,
// select the first one, and convert each SegmentURL element to a tuple.
return segmentLists
.map(function(node) { return XmlUtils.findChildren(node, 'SegmentURL'); })
.reduce(function(all, part) { return all.length > 0 ? all : part; })
.map(function(urlNode) {
var uri = urlNode.getAttribute('media');
var range = XmlUtils.parseAttr(
urlNode, 'mediaRange', XmlUtils.parseRange, {start: 0, end: null});
return {mediaUri: uri, start: range.start, end: range.end};
});
};