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Move MediaSource setup to MediaSourceEngine
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This isolates MediaSource code without changing the early
initialization of MediaSource, which was designed for low-latency
startup.

Prerequisite for #1087, #880, #997, #816

Change-Id: I61acedd95d73610d3e67436d9c7767d643fe2d29
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@joeyparrish
joeyparrish committed Feb 20, 2018
1 parent 917a01d commit b7bcafc
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Showing 12 changed files with 589 additions and 535 deletions.
113 changes: 75 additions & 38 deletions lib/media/media_source_engine.js
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Original file line number Diff line number Diff line change
Expand Up @@ -38,26 +38,18 @@ goog.require('shaka.util.PublicPromise');
* internally synchronized and serialized as needed. Operations that can
* be done in parallel will be done in parallel.
*
* @param {HTMLMediaElement} video The video element, used to read error codes
* when MediaSource operations fail.
* @param {MediaSource} mediaSource The MediaSource, which must be in the
* 'open' state.
* @param {HTMLMediaElement} video The video element, whose source is tied to
* MediaSource during the lifetime of the MediaSourceEngine.
* @param {shakaExtern.TextDisplayer} textDisplayer
*
* @struct
* @constructor
* @implements {shaka.util.IDestroyable}
*/
shaka.media.MediaSourceEngine = function(video, mediaSource, textDisplayer) {
goog.asserts.assert(mediaSource.readyState == 'open',
'The MediaSource should be in the \'open\' state.');

shaka.media.MediaSourceEngine = function(video, textDisplayer) {
/** @private {HTMLMediaElement} */
this.video_ = video;

/** @private {MediaSource} */
this.mediaSource_ = mediaSource;

/** @private {shakaExtern.TextDisplayer} */
this.textDisplayer_ = textDisplayer;

Expand Down Expand Up @@ -85,6 +77,32 @@ shaka.media.MediaSourceEngine = function(video, mediaSource, textDisplayer) {

/** @private {boolean} */
this.useEmbeddedText_ = false;

/** @private {!shaka.util.PublicPromise} */
this.mediaSourceOpen_ = new shaka.util.PublicPromise();

/** @private {MediaSource} */
this.mediaSource_ = this.createMediaSource(this.mediaSourceOpen_);
};


/**
* Create a MediaSource object, attach it to the video element, and return it.
* Resolves the given promise when the MediaSource is ready.
*
* Replaced by unit tests.
*
* @param {!shaka.util.PublicPromise} p
* @return {!MediaSource}
*/
shaka.media.MediaSourceEngine.prototype.createMediaSource = function(p) {
let mediaSource = new MediaSource();

// Set up MediaSource on the video element.
this.eventManager_.listenOnce(mediaSource, 'sourceopen', p.resolve);
this.video_.src = window.URL.createObjectURL(mediaSource);

return mediaSource;
};


Expand Down Expand Up @@ -222,6 +240,10 @@ shaka.media.MediaSourceEngine.prototype.destroy = function() {
cleanup.push(this.transmuxers_[contentType].destroy());
}

if (this.video_) {
this.video_.removeAttribute('src');
this.video_.load();
}

return Promise.all(cleanup).then(function() {
this.eventManager_.destroy();
Expand Down Expand Up @@ -251,43 +273,49 @@ shaka.media.MediaSourceEngine.prototype.destroy = function() {
* reinitialize text streams.
*
* @param {!Object.<shaka.util.ManifestParserUtils.ContentType,
shakaExtern.Stream>} streamsByType
* shakaExtern.Stream>} streamsByType
* A map of content types to streams. All streams must be supported according
* to MediaSourceEngine.isStreamSupported.
*
* @return {!Promise}
*
* @throws InvalidAccessError if blank MIME types are given
* @throws NotSupportedError if unsupported MIME types are given
* @throws QuotaExceededError if the browser can't support that many buffers
*/
shaka.media.MediaSourceEngine.prototype.init = function(streamsByType) {
var ContentType = shaka.util.ManifestParserUtils.ContentType;

for (var contentType in streamsByType) {
var stream = streamsByType[contentType];
goog.asserts.assert(
shaka.media.MediaSourceEngine.isStreamSupported(stream),
'Type negotiation should happen before MediaSourceEngine.init!');

var mimeType = shaka.util.MimeUtils.getFullType(
stream.mimeType, stream.codecs);
if (contentType == ContentType.TEXT) {
this.reinitText(mimeType);
} else {
if (!MediaSource.isTypeSupported(mimeType) &&
shaka.media.Transmuxer.isSupported(contentType, mimeType)) {
this.transmuxers_[contentType] = new shaka.media.Transmuxer();
mimeType =
shaka.media.Transmuxer.convertTsCodecs(contentType, mimeType);
const ContentType = shaka.util.ManifestParserUtils.ContentType;

return this.mediaSourceOpen_.then(() => {
for (let contentType in streamsByType) {
let stream = streamsByType[contentType];
goog.asserts.assert(
shaka.media.MediaSourceEngine.isStreamSupported(stream),
'Type negotiation should happen before MediaSourceEngine.init!');

let mimeType = shaka.util.MimeUtils.getFullType(
stream.mimeType, stream.codecs);
if (contentType == ContentType.TEXT) {
this.reinitText(mimeType);
} else {
if (!MediaSource.isTypeSupported(mimeType) &&
shaka.media.Transmuxer.isSupported(contentType, mimeType)) {
this.transmuxers_[contentType] = new shaka.media.Transmuxer();
mimeType =
shaka.media.Transmuxer.convertTsCodecs(contentType, mimeType);
}
let sourceBuffer = this.mediaSource_.addSourceBuffer(mimeType);
this.eventManager_.listen(
sourceBuffer, 'error',
this.onError_.bind(this, contentType));
this.eventManager_.listen(
sourceBuffer, 'updateend',
this.onUpdateEnd_.bind(this, contentType));
this.sourceBuffers_[contentType] = sourceBuffer;
this.queues_[contentType] = [];
}
var sourceBuffer = this.mediaSource_.addSourceBuffer(mimeType);
this.eventManager_.listen(
sourceBuffer, 'error', this.onError_.bind(this, contentType));
this.eventManager_.listen(
sourceBuffer, 'updateend', this.onUpdateEnd_.bind(this, contentType));
this.sourceBuffers_[contentType] = sourceBuffer;
this.queues_[contentType] = [];
}
}
});
};


Expand All @@ -303,6 +331,15 @@ shaka.media.MediaSourceEngine.prototype.reinitText = function(mimeType) {
};


/**
* @return {boolean} True if the MediaSource is in an "ended" state, or if the
* object has been destroyed.
*/
shaka.media.MediaSourceEngine.prototype.ended = function() {
return this.mediaSource_ ? this.mediaSource_.readyState == 'ended' : true;
};


/**
* Gets the first timestamp in buffer for the given content type.
*
Expand Down
12 changes: 6 additions & 6 deletions lib/media/playhead_observer.js
View file
Original file line number Diff line number Diff line change
Expand Up @@ -37,7 +37,7 @@ goog.require('shaka.util.StreamUtils');
* </ul>
*
* @param {HTMLMediaElement} video
* @param {MediaSource} mediaSource
* @param {shaka.media.MediaSourceEngine} mediaSourceEngine
* @param {shakaExtern.Manifest} manifest
* @param {shakaExtern.StreamingConfiguration} config
* @param {function(boolean)} onBuffering Called and passed true when stopped
Expand All @@ -53,13 +53,13 @@ goog.require('shaka.util.StreamUtils');
* @implements {shaka.util.IDestroyable}
*/
shaka.media.PlayheadObserver = function(
video, mediaSource, manifest, config, onBuffering, onEvent,
video, mediaSourceEngine, manifest, config, onBuffering, onEvent,
onChangePeriod) {
/** @private {HTMLMediaElement} */
this.video_ = video;

/** @private {MediaSource} */
this.mediaSource_ = mediaSource;
/** @private {shaka.media.MediaSourceEngine} */
this.mediaSourceEngine_ = mediaSourceEngine;

/** @private {?shakaExtern.Manifest} */
this.manifest_ = manifest;
Expand Down Expand Up @@ -141,7 +141,7 @@ shaka.media.PlayheadObserver.prototype.destroy = function() {
this.cancelWatchdogTimer_();

this.video_ = null;
this.mediaSource_ = null;
this.mediaSourceEngine_ = null;
this.manifest_ = null;
this.config_ = null;
this.onBuffering_ = null;
Expand Down Expand Up @@ -311,7 +311,7 @@ shaka.media.PlayheadObserver.prototype.onWatchdogTimer_ = function() {
var timeline = this.manifest_.presentationTimeline;
var liveEdge = timeline.getSegmentAvailabilityEnd();
var bufferedToLiveEdge = timeline.isLive() && bufferEnd >= liveEdge;
var noMoreSegments = this.mediaSource_.readyState == 'ended';
let noMoreSegments = this.mediaSourceEngine_.ended();

var atEnd = bufferedToLiveEdge || this.video_.ended || noMoreSegments;
if (!this.buffering_) {
Expand Down
28 changes: 16 additions & 12 deletions lib/media/streaming_engine.js
View file
Original file line number Diff line number Diff line change
Expand Up @@ -508,9 +508,12 @@ shaka.media.StreamingEngine.prototype.loadNewTextStream = function(stream) {
this.textStreamSequenceId_++;
this.unloadingTextStream_ = false;
var currentSequenceId = this.textStreamSequenceId_;
this.playerInterface_.mediaSourceEngine.init({text: stream});

return this.setupStreams_([stream]).then(function() {
let mediaSourceEngine = this.playerInterface_.mediaSourceEngine;

return mediaSourceEngine.init({text: stream}).then(() => {
return this.setupStreams_([stream]);
}).then(() => {
if ((this.textStreamSequenceId_ == currentSequenceId) &&
!this.mediaStates_[ContentType.TEXT] && !this.unloadingTextStream_) {
var playheadTime = this.playerInterface_.playhead.getTime();
Expand All @@ -519,7 +522,7 @@ shaka.media.StreamingEngine.prototype.loadNewTextStream = function(stream) {
this.createMediaState_(stream, needPeriodIndex);
this.scheduleUpdate_(this.mediaStates_[ContentType.TEXT], 0);
}
}.bind(this));
});
};


Expand Down Expand Up @@ -827,24 +830,25 @@ shaka.media.StreamingEngine.prototype.initStreams_ = function(
}

// Init MediaSourceEngine.
this.playerInterface_.mediaSourceEngine.init(streamsByType);
let mediaSourceEngine = this.playerInterface_.mediaSourceEngine;
return mediaSourceEngine.init(streamsByType).then(() => {
this.setDuration_();

this.setDuration_();

// Setup the initial set of Streams and then begin each update cycle. After
// startup completes onUpdate_() will set up the remaining Periods.
return this.setupStreams_(streams).then(function() {
// Setup the initial set of Streams and then begin each update cycle. After
// startup completes onUpdate_() will set up the remaining Periods.
return this.setupStreams_(streams);
}).then(() => {
if (this.destroyed_) return;

for (var type in streamsByType) {
var stream = streamsByType[type];
for (let type in streamsByType) {
let stream = streamsByType[type];
if (!this.mediaStates_[type]) {
this.mediaStates_[type] =
this.createMediaState_(stream, needPeriodIndex, opt_resumeAt);
this.scheduleUpdate_(this.mediaStates_[type], 0);
}
}
}.bind(this));
});
};


Expand Down
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