mirror of
https://github.com/shaka-project/shaka-player.git
synced 2026-06-17 16:26:39 +03:00
Joey Parrish
d562761a3f
This exception was thrown when we attempted to set up a SegmentIterator on CEA tracks. Because they do not have their own segments, this is not possible. The fix is to exclude CEA tracks from this step. Discovered while debugging #2395, but seems to be unrelated. This bug does not affect any release versions. Change-Id: I534b19139d88cc7ad2d6167611c04f400308a71b
1902 lines
65 KiB
JavaScript
1902 lines
65 KiB
JavaScript
/** @license
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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.media.StreamingEngine');
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goog.require('goog.asserts');
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goog.require('shaka.log');
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goog.require('shaka.media.MediaSourceEngine');
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goog.require('shaka.net.Backoff');
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goog.require('shaka.net.NetworkingEngine');
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goog.require('shaka.util.DelayedTick');
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goog.require('shaka.util.Destroyer');
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goog.require('shaka.util.Error');
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goog.require('shaka.util.FakeEvent');
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goog.require('shaka.util.IDestroyable');
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goog.require('shaka.util.ManifestParserUtils');
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goog.require('shaka.util.MimeUtils');
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goog.require('shaka.util.Mp4Parser');
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goog.require('shaka.util.Networking');
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/**
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* @summary Creates a Streaming Engine.
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* The StreamingEngine is responsible for setting up the Manifest's Streams
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* (i.e., for calling each Stream's createSegmentIndex() function), for
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* downloading segments, for co-ordinating audio, video, and text buffering.
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* The StreamingEngine provides an interface to switch between Streams, but it
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* does not choose which Streams to switch to.
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*
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* The StreamingEngine does not need to be notified about changes to the
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* Manifest's SegmentIndexes; however, it does need to be notified when new
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* Variants are added to the Manifest.
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*
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* To start the StreamingEngine the owner must first call configure(), followed
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* by one call to switchVariant(), one optional call to switchTextStream(), and
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* finally a call to start(). After start() resolves, switch*() can be used
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* freely.
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*
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* The owner must call seeked() each time the playhead moves to a new location
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* within the presentation timeline; however, the owner may forego calling
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* seeked() when the playhead moves outside the presentation timeline.
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*
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* @implements {shaka.util.IDestroyable}
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*/
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shaka.media.StreamingEngine = class {
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/**
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* @param {shaka.extern.Manifest} manifest
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* @param {shaka.media.StreamingEngine.PlayerInterface} playerInterface
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*/
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constructor(manifest, playerInterface) {
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/** @private {?shaka.media.StreamingEngine.PlayerInterface} */
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this.playerInterface_ = playerInterface;
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/** @private {?shaka.extern.Manifest} */
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this.manifest_ = manifest;
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/** @private {?shaka.extern.StreamingConfiguration} */
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this.config_ = null;
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/** @private {number} */
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this.bufferingGoalScale_ = 1;
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/** @private {?shaka.extern.Variant} */
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this.currentVariant_ = null;
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/** @private {?shaka.extern.Stream} */
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this.currentTextStream_ = null;
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/**
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* Maps a content type, e.g., 'audio', 'video', or 'text', to a MediaState.
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*
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* @private {!Map.<shaka.util.ManifestParserUtils.ContentType,
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* !shaka.media.StreamingEngine.MediaState_>}
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*/
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this.mediaStates_ = new Map();
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/**
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* Set to true once the initial media states have been created.
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*
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* @private {boolean}
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*/
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this.startupComplete_ = false;
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/**
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* Used for delay and backoff of failure callbacks, so that apps do not
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* retry instantly.
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*
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* @private {shaka.net.Backoff}
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*/
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this.failureCallbackBackoff_ = null;
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/**
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* Set to true on fatal error. Interrupts fetchAndAppend_().
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*
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* @private {boolean}
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*/
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this.fatalError_ = false;
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/** @private {!shaka.util.Destroyer} */
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this.destroyer_ = new shaka.util.Destroyer(() => this.doDestroy_());
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}
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/** @override */
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destroy() {
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return this.destroyer_.destroy();
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}
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/**
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* @return {!Promise}
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* @private
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*/
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doDestroy_() {
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for (const state of this.mediaStates_.values()) {
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this.cancelUpdate_(state);
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}
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this.mediaStates_.clear();
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this.playerInterface_ = null;
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this.manifest_ = null;
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this.config_ = null;
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return Promise.resolve();
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}
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/**
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* Called by the Player to provide an updated configuration any time it
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* changes. Must be called at least once before start().
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*
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* @param {shaka.extern.StreamingConfiguration} config
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*/
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configure(config) {
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this.config_ = config;
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// Create separate parameters for backoff during streaming failure.
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/** @type {shaka.extern.RetryParameters} */
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const failureRetryParams = {
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// The term "attempts" includes the initial attempt, plus all retries.
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// In order to see a delay, there would have to be at least 2 attempts.
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maxAttempts: Math.max(config.retryParameters.maxAttempts, 2),
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baseDelay: config.retryParameters.baseDelay,
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backoffFactor: config.retryParameters.backoffFactor,
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fuzzFactor: config.retryParameters.fuzzFactor,
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timeout: 0, // irrelevant
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};
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// We don't want to ever run out of attempts. The application should be
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// allowed to retry streaming infinitely if it wishes.
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const autoReset = true;
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this.failureCallbackBackoff_ =
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new shaka.net.Backoff(failureRetryParams, autoReset);
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}
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/**
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* Initialize and start streaming.
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*
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* By calling this method, StreamingEngine will start streaming the variant
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* chosen by a prior call to switchVariant(), and optionally, the text stream
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* chosen by a prior call to switchTextStream(). Once the Promise resolves,
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* switch*() may be called freely.
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*
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* @return {!Promise}
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*/
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async start() {
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goog.asserts.assert(this.config_,
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'StreamingEngine configure() must be called before init()!');
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// Setup the initial set of Streams and then begin each update cycle.
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await this.initStreams_();
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this.destroyer_.ensureNotDestroyed();
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shaka.log.debug('init: completed initial Stream setup');
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this.startupComplete_ = true;
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}
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/**
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* Get the current variant we are streaming. Returns null if nothing is
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* streaming.
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* @return {?shaka.extern.Variant}
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*/
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getCurrentVariant() {
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return this.currentVariant_;
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}
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/**
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* Get the text stream we are streaming. Returns null if there is no text
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* streaming.
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* @return {?shaka.extern.Stream}
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*/
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getCurrentTextStream() {
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return this.currentTextStream_;
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}
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/**
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* Start streaming text, creating a new media state.
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*
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* @param {shaka.extern.Stream} stream
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* @return {!Promise}
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* @private
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*/
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async loadNewTextStream_(stream) {
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const ContentType = shaka.util.ManifestParserUtils.ContentType;
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goog.asserts.assert(!this.mediaStates_.has(ContentType.TEXT),
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'Should not call loadNewTextStream_ while streaming text!');
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try {
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// Clear MediaSource's buffered text, so that the new text stream will
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// properly replace the old buffered text.
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// TODO: Should this happen in unloadTextStream() instead?
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await this.playerInterface_.mediaSourceEngine.clear(ContentType.TEXT);
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} catch (error) {
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if (this.playerInterface_) {
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this.playerInterface_.onError(error);
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}
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}
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const mimeType = shaka.util.MimeUtils.getFullType(
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stream.mimeType, stream.codecs);
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this.playerInterface_.mediaSourceEngine.reinitText(mimeType);
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const textDisplayer =
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this.playerInterface_.mediaSourceEngine.getTextDisplayer();
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const streamText =
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textDisplayer.isTextVisible() || this.config_.alwaysStreamText;
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if (streamText) {
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const state = this.createMediaState_(stream);
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this.mediaStates_.set(ContentType.TEXT, state);
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this.scheduleUpdate_(state, 0);
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}
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}
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/**
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* Stop fetching text stream when the user chooses to hide the captions.
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*/
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unloadTextStream() {
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const ContentType = shaka.util.ManifestParserUtils.ContentType;
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const state = this.mediaStates_.get(ContentType.TEXT);
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if (state) {
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this.cancelUpdate_(state);
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this.mediaStates_.delete(ContentType.TEXT);
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}
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}
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/**
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* Set trick play on or off.
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* If trick play is on, related trick play streams will be used when possible.
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* @param {boolean} on
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*/
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setTrickPlay(on) {
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const ContentType = shaka.util.ManifestParserUtils.ContentType;
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const mediaState = this.mediaStates_.get(ContentType.VIDEO);
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if (!mediaState) {
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return;
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}
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const stream = mediaState.stream;
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if (!stream) {
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return;
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}
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shaka.log.debug('setTrickPlay', on);
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if (on) {
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const trickModeVideo = stream.trickModeVideo;
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if (!trickModeVideo) {
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return; // Can't engage trick play.
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}
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const normalVideo = mediaState.restoreStreamAfterTrickPlay;
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if (normalVideo) {
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return; // Already in trick play.
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}
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shaka.log.debug('Engaging trick mode stream', trickModeVideo);
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this.switchInternal_(trickModeVideo, /* clearBuffer= */ false,
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/* safeMargin= */ 0, /* force= */ false);
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mediaState.restoreStreamAfterTrickPlay = stream;
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} else {
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const normalVideo = mediaState.restoreStreamAfterTrickPlay;
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if (!normalVideo) {
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return;
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}
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shaka.log.debug('Restoring non-trick-mode stream', normalVideo);
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mediaState.restoreStreamAfterTrickPlay = null;
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this.switchInternal_(normalVideo, /* clearBuffer= */ true,
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/* safeMargin= */ 0, /* force= */ false);
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}
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}
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/**
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* @param {shaka.extern.Variant} variant
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* @param {boolean=} clearBuffer
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* @param {number=} safeMargin
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*/
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switchVariant(variant, clearBuffer = false, safeMargin = 0) {
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this.currentVariant_ = variant;
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if (!this.startupComplete_) {
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// The selected variant will be used in start().
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return;
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}
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if (variant.video) {
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this.switchInternal_(
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variant.video, /* clearBuffer= */ clearBuffer,
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/* safeMargin= */ safeMargin, /* force= */ false);
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}
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if (variant.audio) {
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this.switchInternal_(
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variant.audio, /* clearBuffer= */ clearBuffer,
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/* safeMargin= */ safeMargin, /* force= */ false);
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}
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}
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/**
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* @param {shaka.extern.Stream} textStream
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*/
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switchTextStream(textStream) {
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this.currentTextStream_ = textStream;
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if (!this.startupComplete_) {
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// The selected text stream will be used in start().
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return;
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}
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const ContentType = shaka.util.ManifestParserUtils.ContentType;
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goog.asserts.assert(textStream && textStream.type == ContentType.TEXT,
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'Wrong stream type passed to switchTextStream!');
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this.switchInternal_(
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textStream, /* clearBuffer= */ true,
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/* safeMargin= */ 0, /* force= */ false);
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}
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/** Reload the current text stream. */
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reloadTextStream() {
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const ContentType = shaka.util.ManifestParserUtils.ContentType;
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const mediaState = this.mediaStates_.get(ContentType.TEXT);
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if (mediaState) { // Don't reload if there's no text to begin with.
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this.switchInternal_(
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mediaState.stream, /* clearBuffer= */ true,
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/* safeMargin= */ 0, /* force= */ true);
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}
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}
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/**
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* Switches to the given Stream. |stream| may be from any Variant.
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*
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* @param {shaka.extern.Stream} stream
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* @param {boolean} clearBuffer
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* @param {number} safeMargin
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* @param {boolean} force
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* If true, reload the text stream even if it did not change.
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* @private
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*/
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switchInternal_(stream, clearBuffer, safeMargin, force) {
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const ContentType = shaka.util.ManifestParserUtils.ContentType;
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const type = /** @type {!ContentType} */(stream.type);
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const mediaState = this.mediaStates_.get(type);
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if (!mediaState && stream.type == ContentType.TEXT) {
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this.loadNewTextStream_(stream);
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return;
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}
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goog.asserts.assert(mediaState, 'switch: expected mediaState to exist');
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if (!mediaState) {
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return;
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}
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if (mediaState.restoreStreamAfterTrickPlay) {
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shaka.log.debug('switch during trick play mode', stream);
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// Already in trick play mode, so stick with trick mode tracks if
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// possible.
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if (stream.trickModeVideo) {
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// Use the trick mode stream, but revert to the new selection later.
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mediaState.restoreStreamAfterTrickPlay = stream;
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stream = stream.trickModeVideo;
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shaka.log.debug('switch found trick play stream', stream);
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} else {
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// There is no special trick mode video for this stream!
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mediaState.restoreStreamAfterTrickPlay = null;
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shaka.log.debug('switch found no special trick play stream');
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}
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}
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if (mediaState.stream == stream && !force) {
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const streamTag = shaka.media.StreamingEngine.logPrefix_(mediaState);
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shaka.log.debug('switch: Stream ' + streamTag + ' already active');
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return;
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}
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if (stream.type == ContentType.TEXT) {
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// Mime types are allowed to change for text streams.
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// Reinitialize the text parser, but only if we are going to fetch the
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// init segment again.
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const fullMimeType = shaka.util.MimeUtils.getFullType(
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stream.mimeType, stream.codecs);
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this.playerInterface_.mediaSourceEngine.reinitText(fullMimeType);
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}
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mediaState.stream = stream;
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if (mediaState.stream.segmentIndex) {
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mediaState.segmentIterator =
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mediaState.stream.segmentIndex[Symbol.iterator]();
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} else {
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mediaState.segmentIterator = null;
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}
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const streamTag = shaka.media.StreamingEngine.logPrefix_(mediaState);
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shaka.log.debug('switch: switching to Stream ' + streamTag);
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if (clearBuffer) {
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if (mediaState.clearingBuffer) {
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// We are already going to clear the buffer, but make sure it is also
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// flushed.
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mediaState.waitingToFlushBuffer = true;
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} else if (mediaState.performingUpdate) {
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// We are performing an update, so we have to wait until it's finished.
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// onUpdate_() will call clearBuffer_() when the update has finished.
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// We need to save the safe margin because its value will be needed when
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// clearing the buffer after the update.
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mediaState.waitingToClearBuffer = true;
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mediaState.clearBufferSafeMargin = safeMargin;
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mediaState.waitingToFlushBuffer = true;
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} else {
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// Cancel the update timer, if any.
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this.cancelUpdate_(mediaState);
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// Clear right away.
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this.clearBuffer_(mediaState, /* flush= */ true, safeMargin)
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.catch((error) => {
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if (this.playerInterface_) {
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this.playerInterface_.onError(error);
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}
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});
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}
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}
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this.makeAbortDecision_(mediaState).catch((error) => {
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if (this.playerInterface_) {
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this.playerInterface_.onError(error);
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}
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});
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}
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/**
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* Decide if it makes sense to abort the current operation, and abort it if
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* so.
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*
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* @param {!shaka.media.StreamingEngine.MediaState_} mediaState
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* @private
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*/
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async makeAbortDecision_(mediaState) {
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// If the operation is completed, it will be set to null, and there's no
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// need to abort the request.
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if (!mediaState.operation) {
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return;
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}
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const originalStream = mediaState.stream;
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const originalOperation = mediaState.operation;
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if (!originalStream.segmentIndex) {
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await originalStream.createSegmentIndex();
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}
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if (mediaState.operation != originalOperation) {
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// The original operation completed while we were getting a segment index,
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// so there's nothing to do now.
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return;
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}
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if (mediaState.stream != originalStream) {
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// The stream changed again while we were getting a segment index. We
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// can't carry out this check, since another one might be in progress by
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// now.
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return;
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}
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mediaState.segmentIterator =
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mediaState.stream.segmentIndex[Symbol.iterator]();
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if (this.shouldAbortCurrentRequest_(mediaState)) {
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shaka.log.info('Aborting current segment request.');
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mediaState.operation.abort();
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}
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}
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/**
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* Returns whether we should abort the current request.
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*
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* @param {!shaka.media.StreamingEngine.MediaState_} mediaState
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* @return {boolean}
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* @private
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*/
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shouldAbortCurrentRequest_(mediaState) {
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goog.asserts.assert(mediaState.operation,
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'Abort logic requires an ongoing operation!');
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const presentationTime = this.playerInterface_.getPresentationTime();
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const bufferEnd =
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this.playerInterface_.mediaSourceEngine.bufferEnd(mediaState.type);
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// The next segment to append from the current stream. This doesn't
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// account for a pending network request and will likely be different from
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// that since we just switched.
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const newSegment = this.getSegmentReferenceNeeded_(
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mediaState, presentationTime, bufferEnd);
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let newSegmentSize = newSegment ? newSegment.getSize() : null;
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if (newSegment && !newSegmentSize) {
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// compute approximate segment size using stream bandwidth
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const duration = newSegment.getEndTime() - newSegment.getStartTime();
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// bandwidth is in bits per second, and the size is in bytes
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newSegmentSize = duration * mediaState.stream.bandwidth / 8;
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}
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|
|
if (isNaN(newSegmentSize)) {
|
|
return false;
|
|
}
|
|
|
|
// When switching, we'll need to download the init segment.
|
|
const init = newSegment.initSegmentReference;
|
|
if (init) {
|
|
newSegmentSize += init.getSize() || 0;
|
|
}
|
|
|
|
const bandwidthEstimate = this.playerInterface_.getBandwidthEstimate();
|
|
|
|
// The estimate is in bits per second, and the size is in bytes. The time
|
|
// remaining is in seconds after this calculation.
|
|
const timeToFetchNewSegment = (newSegmentSize * 8) / bandwidthEstimate;
|
|
|
|
// If the new segment can be finished in time without risking a buffer
|
|
// underflow, we should abort the old one and switch.
|
|
const bufferedAhead = bufferEnd - presentationTime;
|
|
const safetyBuffer = Math.max(
|
|
this.manifest_.minBufferTime || 0,
|
|
this.config_.rebufferingGoal);
|
|
const safeBufferedAhead = bufferedAhead - safetyBuffer;
|
|
if (timeToFetchNewSegment < safeBufferedAhead) {
|
|
return true;
|
|
}
|
|
|
|
// If the thing we want to switch to will be done more quickly than what
|
|
// we've got in progress, we should abort the old one and switch.
|
|
const bytesRemaining = mediaState.operation.getBytesRemaining();
|
|
if (bytesRemaining > newSegmentSize) {
|
|
return true;
|
|
}
|
|
|
|
// Otherwise, complete the operation in progress.
|
|
return false;
|
|
}
|
|
|
|
|
|
/**
|
|
* Notifies the StreamingEngine that the playhead has moved to a valid time
|
|
* within the presentation timeline.
|
|
*/
|
|
seeked() {
|
|
const presentationTime = this.playerInterface_.getPresentationTime();
|
|
const smallGapLimit = this.config_.smallGapLimit;
|
|
const newTimeIsBuffered = (type) => {
|
|
return this.playerInterface_.mediaSourceEngine.isBuffered(
|
|
type, presentationTime, smallGapLimit);
|
|
};
|
|
|
|
let streamCleared = false;
|
|
for (const type of this.mediaStates_.keys()) {
|
|
const bufferEnd =
|
|
this.playerInterface_.mediaSourceEngine.bufferEnd(type);
|
|
const somethingBuffered = bufferEnd != null;
|
|
// Don't clear the buffer unless something is buffered. This extra
|
|
// check prevents extra, useless calls to clear the buffer.
|
|
if (somethingBuffered && !newTimeIsBuffered(type)) {
|
|
// This stream exists, and isn't buffered.
|
|
this.forceClearBuffer_(this.mediaStates_.get(type));
|
|
streamCleared = true;
|
|
}
|
|
}
|
|
|
|
if (!streamCleared) {
|
|
shaka.log.debug(
|
|
'(all): seeked: buffered seek: presentationTime=' + presentationTime);
|
|
}
|
|
}
|
|
|
|
|
|
/**
|
|
* Clear the buffer for a given stream. Unlike clearBuffer_, this will handle
|
|
* cases where a MediaState is performing an update. After this runs, every
|
|
* MediaState will have a pending update.
|
|
* @param {!shaka.media.StreamingEngine.MediaState_} mediaState
|
|
* @private
|
|
*/
|
|
forceClearBuffer_(mediaState) {
|
|
const logPrefix = shaka.media.StreamingEngine.logPrefix_(mediaState);
|
|
|
|
if (mediaState.clearingBuffer) {
|
|
// We're already clearing the buffer, so we don't need to clear the
|
|
// buffer again.
|
|
shaka.log.debug(logPrefix, 'clear: already clearing the buffer');
|
|
return;
|
|
}
|
|
|
|
if (mediaState.waitingToClearBuffer) {
|
|
// May not be performing an update, but an update will still happen.
|
|
// See: https://github.com/google/shaka-player/issues/334
|
|
shaka.log.debug(logPrefix, 'clear: already waiting');
|
|
return;
|
|
}
|
|
|
|
if (mediaState.performingUpdate) {
|
|
// We are performing an update, so we have to wait until it's finished.
|
|
// onUpdate_() will call clearBuffer_() when the update has finished.
|
|
shaka.log.debug(logPrefix, 'clear: currently updating');
|
|
mediaState.waitingToClearBuffer = true;
|
|
// We can set the offset to zero to remember that this was a call to
|
|
// clearAllBuffers.
|
|
mediaState.clearBufferSafeMargin = 0;
|
|
return;
|
|
}
|
|
|
|
const type = mediaState.type;
|
|
if (this.playerInterface_.mediaSourceEngine.bufferStart(type) == null) {
|
|
// Nothing buffered.
|
|
shaka.log.debug(logPrefix, 'clear: nothing buffered');
|
|
if (mediaState.updateTimer == null) {
|
|
// Note: an update cycle stops when we buffer to the end of the
|
|
// presentation, or when we raise an error.
|
|
this.scheduleUpdate_(mediaState, 0);
|
|
}
|
|
return;
|
|
}
|
|
|
|
// An update may be scheduled, but we can just cancel it and clear the
|
|
// buffer right away. Note: clearBuffer_() will schedule the next update.
|
|
shaka.log.debug(logPrefix, 'clear: handling right now');
|
|
this.cancelUpdate_(mediaState);
|
|
this.clearBuffer_(mediaState, /* flush= */ false, 0).catch((error) => {
|
|
if (this.playerInterface_) {
|
|
this.playerInterface_.onError(error);
|
|
}
|
|
});
|
|
}
|
|
|
|
|
|
/**
|
|
* Initializes the initial streams and media states. This will schedule
|
|
* updates for the given types.
|
|
*
|
|
* @return {!Promise}
|
|
* @private
|
|
*/
|
|
async initStreams_() {
|
|
const ContentType = shaka.util.ManifestParserUtils.ContentType;
|
|
|
|
goog.asserts.assert(this.config_,
|
|
'StreamingEngine configure() must be called before init()!');
|
|
|
|
if (!this.currentVariant_) {
|
|
shaka.log.error('init: no Streams chosen');
|
|
throw new shaka.util.Error(
|
|
shaka.util.Error.Severity.CRITICAL,
|
|
shaka.util.Error.Category.STREAMING,
|
|
shaka.util.Error.Code.STREAMING_ENGINE_STARTUP_INVALID_STATE);
|
|
}
|
|
|
|
/**
|
|
* @type {!Map.<shaka.util.ManifestParserUtils.ContentType,
|
|
* shaka.extern.Stream>}
|
|
*/
|
|
const streamsByType = new Map();
|
|
/** @type {!Set.<shaka.extern.Stream>} */
|
|
const streams = new Set();
|
|
|
|
if (this.currentVariant_.audio) {
|
|
streamsByType.set(ContentType.AUDIO, this.currentVariant_.audio);
|
|
streams.add(this.currentVariant_.audio);
|
|
}
|
|
|
|
if (this.currentVariant_.video) {
|
|
streamsByType.set(ContentType.VIDEO, this.currentVariant_.video);
|
|
streams.add(this.currentVariant_.video);
|
|
}
|
|
|
|
if (this.currentTextStream_) {
|
|
streamsByType.set(ContentType.TEXT, this.currentTextStream_);
|
|
streams.add(this.currentTextStream_);
|
|
}
|
|
|
|
// Init MediaSourceEngine.
|
|
const mediaSourceEngine = this.playerInterface_.mediaSourceEngine;
|
|
const forceTransmuxTS = this.config_.forceTransmuxTS;
|
|
|
|
await mediaSourceEngine.init(streamsByType, forceTransmuxTS);
|
|
this.destroyer_.ensureNotDestroyed();
|
|
|
|
this.setDuration_();
|
|
|
|
for (const type of streamsByType.keys()) {
|
|
const stream = streamsByType.get(type);
|
|
if (!this.mediaStates_.has(type)) {
|
|
const state = this.createMediaState_(stream);
|
|
this.mediaStates_.set(type, state);
|
|
this.scheduleUpdate_(state, 0);
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/**
|
|
* Creates a media state.
|
|
*
|
|
* @param {shaka.extern.Stream} stream
|
|
* @return {shaka.media.StreamingEngine.MediaState_}
|
|
* @private
|
|
*/
|
|
createMediaState_(stream) {
|
|
const segmentIterator = stream.segmentIndex ?
|
|
stream.segmentIndex[Symbol.iterator]() : null;
|
|
return /** @type {shaka.media.StreamingEngine.MediaState_} */ ({
|
|
stream,
|
|
type: stream.type,
|
|
lastStream: null,
|
|
segmentIterator,
|
|
lastSegmentReference: null,
|
|
lastInitSegmentReference: null,
|
|
lastTimestampOffset: null,
|
|
lastAppendWindowStart: null,
|
|
lastAppendWindowEnd: null,
|
|
restoreStreamAfterTrickPlay: null,
|
|
endOfStream: false,
|
|
performingUpdate: false,
|
|
updateTimer: null,
|
|
waitingToClearBuffer: false,
|
|
clearBufferSafeMargin: 0,
|
|
waitingToFlushBuffer: false,
|
|
clearingBuffer: false,
|
|
recovering: false,
|
|
hasError: false,
|
|
operation: null,
|
|
});
|
|
}
|
|
|
|
|
|
/**
|
|
* Sets the MediaSource's duration.
|
|
* @private
|
|
*/
|
|
setDuration_() {
|
|
const duration = this.manifest_.presentationTimeline.getDuration();
|
|
if (duration < Infinity) {
|
|
this.playerInterface_.mediaSourceEngine.setDuration(duration);
|
|
} else {
|
|
// Not all platforms support infinite durations, so set a finite duration
|
|
// so we can append segments and so the user agent can seek.
|
|
this.playerInterface_.mediaSourceEngine.setDuration(Math.pow(2, 32));
|
|
}
|
|
}
|
|
|
|
|
|
/**
|
|
* Called when |mediaState|'s update timer has expired.
|
|
*
|
|
* @param {!shaka.media.StreamingEngine.MediaState_} mediaState
|
|
* @private
|
|
*/
|
|
async onUpdate_(mediaState) {
|
|
this.destroyer_.ensureNotDestroyed();
|
|
|
|
const logPrefix = shaka.media.StreamingEngine.logPrefix_(mediaState);
|
|
|
|
// Sanity check.
|
|
goog.asserts.assert(
|
|
!mediaState.performingUpdate && (mediaState.updateTimer != null),
|
|
logPrefix + ' unexpected call to onUpdate_()');
|
|
if (mediaState.performingUpdate || (mediaState.updateTimer == null)) {
|
|
return;
|
|
}
|
|
|
|
goog.asserts.assert(
|
|
!mediaState.clearingBuffer, logPrefix +
|
|
' onUpdate_() should not be called when clearing the buffer');
|
|
if (mediaState.clearingBuffer) {
|
|
return;
|
|
}
|
|
|
|
mediaState.updateTimer = null;
|
|
|
|
// Handle pending buffer clears.
|
|
if (mediaState.waitingToClearBuffer) {
|
|
// Note: clearBuffer_() will schedule the next update.
|
|
shaka.log.debug(logPrefix, 'skipping update and clearing the buffer');
|
|
await this.clearBuffer_(
|
|
mediaState, mediaState.waitingToFlushBuffer,
|
|
mediaState.clearBufferSafeMargin);
|
|
return;
|
|
}
|
|
|
|
// Make sure the segment index exists.
|
|
if (!mediaState.stream.segmentIndex) {
|
|
const thisStream = mediaState.stream;
|
|
|
|
await mediaState.stream.createSegmentIndex();
|
|
|
|
if (thisStream != mediaState.stream) {
|
|
// We switched streams while in the middle of this async call to
|
|
// createSegmentIndex. Abandon this update and schedule a new one if
|
|
// there's not already one pending.
|
|
if (mediaState.updateTimer == null) {
|
|
this.scheduleUpdate_(mediaState, 0);
|
|
}
|
|
return;
|
|
}
|
|
|
|
if (!shaka.media.StreamingEngine.isEmbeddedText_(mediaState)) {
|
|
goog.asserts.assert(mediaState.stream.segmentIndex,
|
|
'Segment index should exist by now!');
|
|
|
|
mediaState.segmentIterator =
|
|
mediaState.stream.segmentIndex[Symbol.iterator]();
|
|
}
|
|
}
|
|
|
|
// Update the MediaState.
|
|
try {
|
|
const delay = this.update_(mediaState);
|
|
if (delay != null) {
|
|
this.scheduleUpdate_(mediaState, delay);
|
|
mediaState.hasError = false;
|
|
}
|
|
} catch (error) {
|
|
this.handleStreamingError_(error);
|
|
return;
|
|
}
|
|
|
|
const mediaStates = Array.from(this.mediaStates_.values());
|
|
|
|
// Check if we've buffered to the end of the presentation. We delay adding
|
|
// the audio and video media states, so it is possible for the text stream
|
|
// to be the only state and buffer to the end. So we need to wait until we
|
|
// have completed startup to determine if we have reached the end.
|
|
if (this.startupComplete_ &&
|
|
mediaStates.every((ms) => ms.endOfStream)) {
|
|
shaka.log.v1(logPrefix, 'calling endOfStream()...');
|
|
await this.playerInterface_.mediaSourceEngine.endOfStream();
|
|
this.destroyer_.ensureNotDestroyed();
|
|
|
|
// If the media segments don't reach the end, then we need to update the
|
|
// timeline duration to match the final media duration to avoid
|
|
// buffering forever at the end.
|
|
// We should only do this if the duration needs to shrink.
|
|
// Growing it by less than 1ms can actually cause buffering on
|
|
// replay, as in https://github.com/google/shaka-player/issues/979
|
|
// On some platforms, this can spuriously be 0, so ignore this case.
|
|
// https://github.com/google/shaka-player/issues/1967,
|
|
const duration = this.playerInterface_.mediaSourceEngine.getDuration();
|
|
if (duration != 0 &&
|
|
duration < this.manifest_.presentationTimeline.getDuration()) {
|
|
this.manifest_.presentationTimeline.setDuration(duration);
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/**
|
|
* Updates the given MediaState.
|
|
*
|
|
* @param {shaka.media.StreamingEngine.MediaState_} mediaState
|
|
* @return {?number} The number of seconds to wait until updating again or
|
|
* null if another update does not need to be scheduled.
|
|
* @private
|
|
*/
|
|
update_(mediaState) {
|
|
goog.asserts.assert(this.manifest_, 'manifest_ should not be null');
|
|
goog.asserts.assert(this.config_, 'config_ should not be null');
|
|
|
|
const ContentType = shaka.util.ManifestParserUtils.ContentType;
|
|
|
|
// Do not schedule update for closed captions text mediastate, since closed
|
|
// captions are embedded in video streams.
|
|
if (shaka.media.StreamingEngine.isEmbeddedText_(mediaState)) {
|
|
this.playerInterface_.mediaSourceEngine.setSelectedClosedCaptionId(
|
|
mediaState.stream.originalId || '');
|
|
return null;
|
|
}
|
|
|
|
const logPrefix = shaka.media.StreamingEngine.logPrefix_(mediaState);
|
|
|
|
// Compute how far we've buffered ahead of the playhead.
|
|
const presentationTime = this.playerInterface_.getPresentationTime();
|
|
|
|
// Get the next timestamp we need.
|
|
const timeNeeded = this.getTimeNeeded_(mediaState, presentationTime);
|
|
shaka.log.v2(logPrefix, 'timeNeeded=' + timeNeeded);
|
|
|
|
// Get the amount of content we have buffered, accounting for drift. This
|
|
// is only used to determine if we have meet the buffering goal. This
|
|
// should be the same method that PlayheadObserver uses.
|
|
const bufferedAhead =
|
|
this.playerInterface_.mediaSourceEngine.bufferedAheadOf(
|
|
mediaState.type, presentationTime);
|
|
|
|
shaka.log.v2(logPrefix,
|
|
'update_:',
|
|
'presentationTime=' + presentationTime,
|
|
'bufferedAhead=' + bufferedAhead);
|
|
|
|
const unscaledBufferingGoal = Math.max(
|
|
this.manifest_.minBufferTime || 0,
|
|
this.config_.rebufferingGoal,
|
|
this.config_.bufferingGoal);
|
|
|
|
const scaledBufferingGoal =
|
|
unscaledBufferingGoal * this.bufferingGoalScale_;
|
|
|
|
// Check if we've buffered to the end of the presentation.
|
|
if (timeNeeded >= this.manifest_.presentationTimeline.getDuration()) {
|
|
// We shouldn't rebuffer if the playhead is close to the end of the
|
|
// presentation.
|
|
shaka.log.debug(logPrefix, 'buffered to end of presentation');
|
|
mediaState.endOfStream = true;
|
|
|
|
if (mediaState.type == ContentType.VIDEO) {
|
|
// Since the text stream of CEA closed captions doesn't have update
|
|
// timer, we have to set the text endOfStream based on the video
|
|
// stream's endOfStream state.
|
|
const textState = this.mediaStates_.get(ContentType.TEXT);
|
|
if (textState &&
|
|
shaka.media.StreamingEngine.isEmbeddedText_(textState)) {
|
|
textState.endOfStream = true;
|
|
}
|
|
}
|
|
return null;
|
|
}
|
|
mediaState.endOfStream = false;
|
|
|
|
// If we've buffered to the buffering goal then schedule an update.
|
|
if (bufferedAhead >= scaledBufferingGoal) {
|
|
shaka.log.v2(logPrefix, 'buffering goal met');
|
|
|
|
// Do not try to predict the next update. Just poll twice every second.
|
|
// The playback rate can change at any time, so any prediction we make now
|
|
// could be terribly invalid soon.
|
|
return 0.5;
|
|
}
|
|
|
|
const bufferEnd =
|
|
this.playerInterface_.mediaSourceEngine.bufferEnd(mediaState.type);
|
|
const reference = this.getSegmentReferenceNeeded_(
|
|
mediaState, presentationTime, bufferEnd);
|
|
if (!reference ||
|
|
!this.isSegmentReferenceAvailable_(mediaState, reference)) {
|
|
// The segment could not be found, does not exist, or is not available.
|
|
// In any case just try again... if the manifest is incomplete or is not
|
|
// being updated then we'll idle forever; otherwise, we'll end up getting
|
|
// a SegmentReference eventually.
|
|
return 1;
|
|
}
|
|
|
|
// Do not let any one stream get far ahead of any other.
|
|
let minTimeNeeded = Infinity;
|
|
const mediaStates = Array.from(this.mediaStates_.values());
|
|
for (const otherState of mediaStates) {
|
|
// Do not consider embedded captions in this calculation. It could lead
|
|
// to hangs in streaming.
|
|
if (shaka.media.StreamingEngine.isEmbeddedText_(otherState)) {
|
|
continue;
|
|
}
|
|
|
|
const timeNeeded = this.getTimeNeeded_(otherState, presentationTime);
|
|
minTimeNeeded = Math.min(minTimeNeeded, timeNeeded);
|
|
}
|
|
|
|
const maxSegmentDuration =
|
|
this.manifest_.presentationTimeline.getMaxSegmentDuration();
|
|
const maxRunAhead = maxSegmentDuration *
|
|
shaka.media.StreamingEngine.MAX_RUN_AHEAD_SEGMENTS_;
|
|
if (timeNeeded >= minTimeNeeded + maxRunAhead) {
|
|
// Wait and give other media types time to catch up to this one.
|
|
// For example, let video buffering catch up to audio buffering before
|
|
// fetching another audio segment.
|
|
return 1;
|
|
}
|
|
|
|
const p = this.fetchAndAppend_(mediaState, presentationTime, reference);
|
|
p.catch(() => {}); // TODO(#1993): Handle asynchronous errors.
|
|
return null;
|
|
}
|
|
|
|
|
|
/**
|
|
* Gets the next timestamp needed. Returns the playhead's position if the
|
|
* buffer is empty; otherwise, returns the time at which the last segment
|
|
* appended ends.
|
|
*
|
|
* @param {shaka.media.StreamingEngine.MediaState_} mediaState
|
|
* @param {number} presentationTime
|
|
* @return {number} The next timestamp needed.
|
|
* @private
|
|
*/
|
|
getTimeNeeded_(mediaState, presentationTime) {
|
|
// Get the next timestamp we need. We must use |lastSegmentReference|
|
|
// to determine this and not the actual buffer for two reasons:
|
|
// 1. Actual segments end slightly before their advertised end times, so
|
|
// the next timestamp we need is actually larger than |bufferEnd|.
|
|
// 2. There may be drift (the timestamps in the segments are ahead/behind
|
|
// of the timestamps in the manifest), but we need drift-free times
|
|
// when comparing times against the presentation timeline.
|
|
if (!mediaState.lastStream || !mediaState.lastSegmentReference) {
|
|
return presentationTime;
|
|
}
|
|
|
|
return mediaState.lastSegmentReference.endTime;
|
|
}
|
|
|
|
|
|
/**
|
|
* Gets the SegmentReference of the next segment needed.
|
|
*
|
|
* @param {shaka.media.StreamingEngine.MediaState_} mediaState
|
|
* @param {number} presentationTime
|
|
* @param {?number} bufferEnd
|
|
* @return {shaka.media.SegmentReference} The SegmentReference of the
|
|
* next segment needed. Returns null if a segment could not be found, does
|
|
* not exist, or is not available.
|
|
* @private
|
|
*/
|
|
getSegmentReferenceNeeded_(mediaState, presentationTime, bufferEnd) {
|
|
const logPrefix = shaka.media.StreamingEngine.logPrefix_(mediaState);
|
|
|
|
if (mediaState.stream == mediaState.lastStream) {
|
|
// Something is buffered from the same Stream. Use the current position
|
|
// in the segment index. This is updated via next() after each segment is
|
|
// appended.
|
|
return mediaState.segmentIterator.current();
|
|
} else if (mediaState.lastSegmentReference) {
|
|
// Something is buffered from another Stream.
|
|
goog.asserts.assert(mediaState.lastStream,
|
|
'lastStream should not be null');
|
|
|
|
shaka.log.v1(logPrefix, 'looking up segment from new stream',
|
|
'endTime:', mediaState.lastSegmentReference.endTime);
|
|
|
|
const ref = mediaState.segmentIterator.seek(
|
|
mediaState.lastSegmentReference.endTime);
|
|
if (ref == null) {
|
|
shaka.log.warning(logPrefix, 'cannot find segment',
|
|
'endTime:', mediaState.lastSegmentReference.endTime);
|
|
}
|
|
return ref;
|
|
} else if (bufferEnd) {
|
|
// We still have something buffered. Use that to find the next segment.
|
|
goog.asserts.assert(!mediaState.lastStream, 'lastStream should be null');
|
|
|
|
shaka.log.v1(logPrefix, 'looking up segment',
|
|
'bufferEnd:', bufferEnd);
|
|
|
|
const ref = mediaState.segmentIterator.seek(bufferEnd);
|
|
if (ref == null) {
|
|
shaka.log.warning(logPrefix, 'cannot find segment',
|
|
'bufferEnd:', bufferEnd);
|
|
}
|
|
return ref;
|
|
} else {
|
|
// Nothing is buffered. Start at the playhead time.
|
|
goog.asserts.assert(!mediaState.lastStream, 'lastStream should be null');
|
|
|
|
// If there's positive drift then we need to adjust the lookup time, and
|
|
// may wind up requesting the previous segment to be safe.
|
|
const maxDrift = this.config_.inaccurateManifestTolerance;
|
|
const lookupTime = Math.max(presentationTime - maxDrift, 0);
|
|
|
|
shaka.log.v1(logPrefix, 'looking up segment',
|
|
'lookupTime:', lookupTime,
|
|
'presentationTime:', presentationTime);
|
|
|
|
const ref = mediaState.segmentIterator.seek(lookupTime);
|
|
if (ref == null) {
|
|
shaka.log.warning(logPrefix, 'cannot find segment',
|
|
'lookupTime:', lookupTime,
|
|
'presentationTime:', presentationTime);
|
|
}
|
|
return ref;
|
|
}
|
|
}
|
|
|
|
|
|
/**
|
|
* Checks a SegmentReference against the timeline to see if it is available.
|
|
* In some cases, we may have references that are not yet available or no
|
|
* longer available according to the timeline. We shouldn't fetch those.
|
|
*
|
|
* @param {shaka.media.StreamingEngine.MediaState_} mediaState
|
|
* @param {shaka.media.SegmentReference} reference
|
|
* @return {boolean}
|
|
* @private
|
|
*/
|
|
isSegmentReferenceAvailable_(mediaState, reference) {
|
|
const logPrefix = shaka.media.StreamingEngine.logPrefix_(mediaState);
|
|
const timeline = this.manifest_.presentationTimeline;
|
|
const availabilityStart = timeline.getSegmentAvailabilityStart();
|
|
const availabilityEnd = timeline.getSegmentAvailabilityEnd();
|
|
|
|
if (reference.endTime < availabilityStart ||
|
|
reference.startTime > availabilityEnd) {
|
|
shaka.log.v2(logPrefix,
|
|
'segment is not available:',
|
|
'reference.startTime=' + reference.startTime,
|
|
'reference.endTime=' + reference.endTime,
|
|
'availabilityStart=' + availabilityStart,
|
|
'availabilityEnd=' + availabilityEnd);
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
|
|
/**
|
|
* Fetches and appends the given segment. Sets up the given MediaState's
|
|
* associated SourceBuffer and evicts segments if either are required
|
|
* beforehand. Schedules another update after completing successfully.
|
|
*
|
|
* @param {!shaka.media.StreamingEngine.MediaState_} mediaState
|
|
* @param {number} presentationTime
|
|
* @param {!shaka.media.SegmentReference} reference
|
|
* @private
|
|
*/
|
|
async fetchAndAppend_(mediaState, presentationTime, reference) {
|
|
const ContentType = shaka.util.ManifestParserUtils.ContentType;
|
|
const StreamingEngine = shaka.media.StreamingEngine;
|
|
const logPrefix = StreamingEngine.logPrefix_(mediaState);
|
|
|
|
shaka.log.v1(logPrefix,
|
|
'fetchAndAppend_:',
|
|
'presentationTime=' + presentationTime,
|
|
'reference.startTime=' + reference.startTime,
|
|
'reference.endTime=' + reference.endTime);
|
|
|
|
// Subtlety: The playhead may move while asynchronous update operations are
|
|
// in progress, so we should avoid calling playhead.getTime() in any
|
|
// callbacks. Furthermore, switch() may be called at any time, so we should
|
|
// also avoid using mediaState.stream in any callbacks.
|
|
const stream = mediaState.stream;
|
|
|
|
mediaState.performingUpdate = true;
|
|
|
|
const initSourceBuffer = this.initSourceBuffer_(mediaState, reference);
|
|
|
|
shaka.log.v2(logPrefix, 'fetching segment');
|
|
const fetchSegment = this.fetch_(mediaState, reference);
|
|
|
|
try {
|
|
const results = await Promise.all([initSourceBuffer, fetchSegment]);
|
|
this.destroyer_.ensureNotDestroyed();
|
|
if (this.fatalError_) {
|
|
return;
|
|
}
|
|
await this.append_(
|
|
mediaState, presentationTime, stream, reference, results[1]);
|
|
this.destroyer_.ensureNotDestroyed();
|
|
if (this.fatalError_) {
|
|
return;
|
|
}
|
|
|
|
mediaState.performingUpdate = false;
|
|
mediaState.recovering = false;
|
|
|
|
const info = this.playerInterface_.mediaSourceEngine.getBufferedInfo();
|
|
const buffered = info[mediaState.type];
|
|
shaka.log.v1(logPrefix, 'finished fetch and append', buffered);
|
|
|
|
if (!mediaState.waitingToClearBuffer) {
|
|
this.playerInterface_.onSegmentAppended();
|
|
}
|
|
|
|
// Update right away.
|
|
this.scheduleUpdate_(mediaState, 0);
|
|
} catch (error) {
|
|
this.destroyer_.ensureNotDestroyed(error);
|
|
if (this.fatalError_) {
|
|
return;
|
|
}
|
|
goog.asserts.assert(error instanceof shaka.util.Error,
|
|
'Should only receive a Shaka error');
|
|
|
|
mediaState.performingUpdate = false;
|
|
|
|
if (mediaState.type == ContentType.TEXT &&
|
|
this.config_.ignoreTextStreamFailures) {
|
|
if (error.code == shaka.util.Error.Code.BAD_HTTP_STATUS) {
|
|
shaka.log.warning(logPrefix,
|
|
'Text stream failed to download. Proceeding without it.');
|
|
} else {
|
|
shaka.log.warning(logPrefix,
|
|
'Text stream failed to parse. Proceeding without it.');
|
|
}
|
|
this.mediaStates_.delete(ContentType.TEXT);
|
|
} else if (error.code == shaka.util.Error.Code.OPERATION_ABORTED) {
|
|
// If the network slows down, abort the current fetch request and start
|
|
// a new one, and ignore the error message.
|
|
mediaState.performingUpdate = false;
|
|
mediaState.updateTimer = null;
|
|
this.scheduleUpdate_(mediaState, 0);
|
|
} else if (error.code == shaka.util.Error.Code.QUOTA_EXCEEDED_ERROR) {
|
|
this.handleQuotaExceeded_(mediaState, error);
|
|
} else {
|
|
shaka.log.error(logPrefix, 'failed fetch and append: code=' +
|
|
error.code);
|
|
mediaState.hasError = true;
|
|
|
|
error.severity = shaka.util.Error.Severity.CRITICAL;
|
|
this.handleStreamingError_(error);
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/**
|
|
* Clear per-stream error states and retry any failed streams.
|
|
* @return {boolean} False if unable to retry.
|
|
*/
|
|
retry() {
|
|
if (this.destroyer_.destroyed()) {
|
|
shaka.log.error('Unable to retry after StreamingEngine is destroyed!');
|
|
return false;
|
|
}
|
|
|
|
if (this.fatalError_) {
|
|
shaka.log.error('Unable to retry after StreamingEngine encountered a ' +
|
|
'fatal error!');
|
|
return false;
|
|
}
|
|
|
|
for (const mediaState of this.mediaStates_.values()) {
|
|
const logPrefix = shaka.media.StreamingEngine.logPrefix_(mediaState);
|
|
if (mediaState.hasError) {
|
|
shaka.log.info(logPrefix, 'Retrying after failure...');
|
|
mediaState.hasError = false;
|
|
this.scheduleUpdate_(mediaState, 0.1);
|
|
}
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
|
|
/**
|
|
* Handles a QUOTA_EXCEEDED_ERROR.
|
|
*
|
|
* @param {shaka.media.StreamingEngine.MediaState_} mediaState
|
|
* @param {!shaka.util.Error} error
|
|
* @private
|
|
*/
|
|
handleQuotaExceeded_(mediaState, error) {
|
|
const logPrefix = shaka.media.StreamingEngine.logPrefix_(mediaState);
|
|
|
|
// The segment cannot fit into the SourceBuffer. Ideally, MediaSource would
|
|
// have evicted old data to accommodate the segment; however, it may have
|
|
// failed to do this if the segment is very large, or if it could not find
|
|
// a suitable time range to remove.
|
|
//
|
|
// We can overcome the latter by trying to append the segment again;
|
|
// however, to avoid continuous QuotaExceededErrors we must reduce the size
|
|
// of the buffer going forward.
|
|
//
|
|
// If we've recently reduced the buffering goals, wait until the stream
|
|
// which caused the first QuotaExceededError recovers. Doing this ensures
|
|
// we don't reduce the buffering goals too quickly.
|
|
|
|
const mediaStates = Array.from(this.mediaStates_.values());
|
|
const waitingForAnotherStreamToRecover = mediaStates.some((ms) => {
|
|
return ms != mediaState && ms.recovering;
|
|
});
|
|
|
|
if (!waitingForAnotherStreamToRecover) {
|
|
// Reduction schedule: 80%, 60%, 40%, 20%, 16%, 12%, 8%, 4%, fail.
|
|
// Note: percentages are used for comparisons to avoid rounding errors.
|
|
const percentBefore = Math.round(100 * this.bufferingGoalScale_);
|
|
if (percentBefore > 20) {
|
|
this.bufferingGoalScale_ -= 0.2;
|
|
} else if (percentBefore > 4) {
|
|
this.bufferingGoalScale_ -= 0.04;
|
|
} else {
|
|
shaka.log.error(
|
|
logPrefix, 'MediaSource threw QuotaExceededError too many times');
|
|
mediaState.hasError = true;
|
|
this.fatalError_ = true;
|
|
this.playerInterface_.onError(error);
|
|
return;
|
|
}
|
|
const percentAfter = Math.round(100 * this.bufferingGoalScale_);
|
|
shaka.log.warning(
|
|
logPrefix,
|
|
'MediaSource threw QuotaExceededError:',
|
|
'reducing buffering goals by ' + (100 - percentAfter) + '%');
|
|
mediaState.recovering = true;
|
|
} else {
|
|
shaka.log.debug(
|
|
logPrefix,
|
|
'MediaSource threw QuotaExceededError:',
|
|
'waiting for another stream to recover...');
|
|
}
|
|
|
|
// QuotaExceededError gets thrown if evication didn't help to make room
|
|
// for a segment. We want to wait for a while (4 seconds is just an
|
|
// arbitrary number) before updating to give the playhead a chance to
|
|
// advance, so we don't immidiately throw again.
|
|
this.scheduleUpdate_(mediaState, 4);
|
|
}
|
|
|
|
|
|
/**
|
|
* Sets the given MediaState's associated SourceBuffer's timestamp offset,
|
|
* append window, and init segment if they have changed. If an error occurs
|
|
* then neither the timestamp offset or init segment are unset, since another
|
|
* call to switch() will end up superseding them.
|
|
*
|
|
* @param {shaka.media.StreamingEngine.MediaState_} mediaState
|
|
* @param {!shaka.media.SegmentReference} reference
|
|
* @return {!Promise}
|
|
* @private
|
|
*/
|
|
async initSourceBuffer_(mediaState, reference) {
|
|
const StreamingEngine = shaka.media.StreamingEngine;
|
|
const logPrefix = StreamingEngine.logPrefix_(mediaState);
|
|
|
|
/** @type {!Array.<!Promise>} */
|
|
const operations = [];
|
|
|
|
// Rounding issues can cause us to remove the first frame of a Period, so
|
|
// reduce the window start time slightly.
|
|
const appendWindowStart = Math.max(0,
|
|
reference.appendWindowStart -
|
|
StreamingEngine.APPEND_WINDOW_START_FUDGE_);
|
|
const appendWindowEnd =
|
|
reference.appendWindowEnd + StreamingEngine.APPEND_WINDOW_END_FUDGE_;
|
|
|
|
goog.asserts.assert(
|
|
reference.startTime <= appendWindowEnd,
|
|
logPrefix + ' segment should start before append window end');
|
|
|
|
const timestampOffset = reference.timestampOffset;
|
|
if (timestampOffset != mediaState.lastTimestampOffset ||
|
|
appendWindowStart != mediaState.lastAppendWindowStart ||
|
|
appendWindowEnd != mediaState.lastAppendWindowEnd) {
|
|
shaka.log.v1(logPrefix, 'setting timestamp offset to ' + timestampOffset);
|
|
shaka.log.v1(logPrefix,
|
|
'setting append window start to ' + appendWindowStart);
|
|
shaka.log.v1(logPrefix,
|
|
'setting append window end to ' + appendWindowEnd);
|
|
|
|
const setProperties = async () => {
|
|
try {
|
|
mediaState.lastAppendWindowStart = appendWindowStart;
|
|
mediaState.lastAppendWindowEnd = appendWindowEnd;
|
|
mediaState.lastTimestampOffset = timestampOffset;
|
|
|
|
await this.playerInterface_.mediaSourceEngine.setStreamProperties(
|
|
mediaState.type, timestampOffset, appendWindowStart,
|
|
appendWindowEnd);
|
|
} catch (error) {
|
|
mediaState.lastAppendWindowStart = null;
|
|
mediaState.lastAppendWindowEnd = null;
|
|
mediaState.lastTimestampOffset = null;
|
|
|
|
throw error;
|
|
}
|
|
};
|
|
operations.push(setProperties());
|
|
}
|
|
|
|
if (reference.initSegmentReference != mediaState.lastInitSegmentReference) {
|
|
mediaState.lastInitSegmentReference = reference.initSegmentReference;
|
|
|
|
if (reference.initSegmentReference) {
|
|
shaka.log.v1(logPrefix, 'fetching init segment');
|
|
|
|
const fetchInit =
|
|
this.fetch_(mediaState, reference.initSegmentReference);
|
|
const append = async () => {
|
|
try {
|
|
const initSegment = await fetchInit;
|
|
this.destroyer_.ensureNotDestroyed();
|
|
shaka.log.v1(logPrefix, 'appending init segment');
|
|
const hasClosedCaptions = mediaState.stream.closedCaptions &&
|
|
mediaState.stream.closedCaptions.size > 0;
|
|
await this.playerInterface_.mediaSourceEngine.appendBuffer(
|
|
mediaState.type, initSegment, /* startTime= */ null,
|
|
/* endTime= */ null, hasClosedCaptions);
|
|
} catch (error) {
|
|
mediaState.lastInitSegmentReference = null;
|
|
throw error;
|
|
}
|
|
};
|
|
operations.push(append());
|
|
}
|
|
}
|
|
|
|
await Promise.all(operations);
|
|
}
|
|
|
|
|
|
/**
|
|
* Appends the given segment and evicts content if required to append.
|
|
*
|
|
* @param {!shaka.media.StreamingEngine.MediaState_} mediaState
|
|
* @param {number} presentationTime
|
|
* @param {shaka.extern.Stream} stream
|
|
* @param {!shaka.media.SegmentReference} reference
|
|
* @param {BufferSource} segment
|
|
* @return {!Promise}
|
|
* @private
|
|
*/
|
|
async append_(mediaState, presentationTime, stream, reference,
|
|
segment) {
|
|
const logPrefix = shaka.media.StreamingEngine.logPrefix_(mediaState);
|
|
|
|
const hasClosedCaptions = stream.closedCaptions &&
|
|
stream.closedCaptions.size > 0;
|
|
if (stream.emsgSchemeIdUris != null && stream.emsgSchemeIdUris.length > 0) {
|
|
new shaka.util.Mp4Parser()
|
|
.fullBox(
|
|
'emsg',
|
|
(box) => this.parseEMSG_(
|
|
reference, stream.emsgSchemeIdUris, box))
|
|
.parse(segment);
|
|
}
|
|
|
|
await this.evict_(mediaState, presentationTime);
|
|
this.destroyer_.ensureNotDestroyed();
|
|
shaka.log.v1(logPrefix, 'appending media segment');
|
|
|
|
await this.playerInterface_.mediaSourceEngine.appendBuffer(
|
|
mediaState.type,
|
|
segment,
|
|
reference.startTime,
|
|
reference.endTime,
|
|
hasClosedCaptions);
|
|
this.destroyer_.ensureNotDestroyed();
|
|
shaka.log.v2(logPrefix, 'appended media segment');
|
|
|
|
// We must use |stream| instead of |mediaState.stream| because switch() may
|
|
// have been called.
|
|
mediaState.lastStream = stream;
|
|
mediaState.lastSegmentReference = reference;
|
|
// Only advance the segmentIterator if the stream hasn't changed.
|
|
if (mediaState.stream == stream) {
|
|
const ref = mediaState.segmentIterator.next().value;
|
|
shaka.log.v2(logPrefix, 'advancing to next segment', ref);
|
|
}
|
|
}
|
|
|
|
|
|
/**
|
|
* Parse the EMSG box from a MP4 container.
|
|
*
|
|
* @param {!shaka.media.SegmentReference} reference
|
|
* @param {?Array.<string>} emsgSchemeIdUris Array of emsg
|
|
* scheme_id_uri for which emsg boxes should be parsed.
|
|
* @param {!shaka.extern.ParsedBox} box
|
|
* @private
|
|
*/
|
|
parseEMSG_(reference, emsgSchemeIdUris, box) {
|
|
const schemeId = box.reader.readTerminatedString();
|
|
// Read the rest of the data.
|
|
const value = box.reader.readTerminatedString();
|
|
const timescale = box.reader.readUint32();
|
|
const presentationTimeDelta = box.reader.readUint32();
|
|
const eventDuration = box.reader.readUint32();
|
|
const id = box.reader.readUint32();
|
|
const messageData = box.reader.readBytes(
|
|
box.reader.getLength() - box.reader.getPosition());
|
|
|
|
const startTime = reference.startTime + (presentationTimeDelta / timescale);
|
|
|
|
// See DASH sec. 5.10.3.3.1
|
|
// If a DASH client detects an event message box with a scheme that is not
|
|
// defined in MPD, the client is expected to ignore it.
|
|
if (emsgSchemeIdUris.includes(schemeId)) {
|
|
// See DASH sec. 5.10.4.1
|
|
// A special scheme in DASH used to signal manifest updates.
|
|
if (schemeId == 'urn:mpeg:dash:event:2012') {
|
|
this.playerInterface_.onManifestUpdate();
|
|
} else {
|
|
/** @type {shaka.extern.EmsgInfo} */
|
|
const emsg = {
|
|
startTime: startTime,
|
|
endTime: startTime + (eventDuration / timescale),
|
|
schemeIdUri: schemeId,
|
|
value: value,
|
|
timescale: timescale,
|
|
presentationTimeDelta: presentationTimeDelta,
|
|
eventDuration: eventDuration,
|
|
id: id,
|
|
messageData: messageData,
|
|
};
|
|
|
|
// Dispatch an event to notify the application about the emsg box.
|
|
const eventName = shaka.Player.EventName.Emsg;
|
|
const event = new shaka.util.FakeEvent(eventName, {'detail': emsg});
|
|
this.playerInterface_.onEvent(event);
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/**
|
|
* Evicts media to meet the max buffer behind limit.
|
|
*
|
|
* @param {shaka.media.StreamingEngine.MediaState_} mediaState
|
|
* @param {number} presentationTime
|
|
* @private
|
|
*/
|
|
async evict_(mediaState, presentationTime) {
|
|
const logPrefix = shaka.media.StreamingEngine.logPrefix_(mediaState);
|
|
shaka.log.v2(logPrefix, 'checking buffer length');
|
|
|
|
// Use the max segment duration, if it is longer than the bufferBehind, to
|
|
// avoid accidentally clearing too much data when dealing with a manifest
|
|
// with a long keyframe interval.
|
|
const bufferBehind = Math.max(this.config_.bufferBehind,
|
|
this.manifest_.presentationTimeline.getMaxSegmentDuration());
|
|
|
|
const startTime =
|
|
this.playerInterface_.mediaSourceEngine.bufferStart(mediaState.type);
|
|
if (startTime == null) {
|
|
shaka.log.v2(logPrefix,
|
|
'buffer behind okay because nothing buffered:',
|
|
'presentationTime=' + presentationTime,
|
|
'bufferBehind=' + bufferBehind);
|
|
return;
|
|
}
|
|
const bufferedBehind = presentationTime - startTime;
|
|
|
|
const overflow = bufferedBehind - bufferBehind;
|
|
if (overflow <= 0) {
|
|
shaka.log.v2(logPrefix,
|
|
'buffer behind okay:',
|
|
'presentationTime=' + presentationTime,
|
|
'bufferedBehind=' + bufferedBehind,
|
|
'bufferBehind=' + bufferBehind,
|
|
'underflow=' + (-overflow));
|
|
return;
|
|
}
|
|
|
|
shaka.log.v1(logPrefix,
|
|
'buffer behind too large:',
|
|
'presentationTime=' + presentationTime,
|
|
'bufferedBehind=' + bufferedBehind,
|
|
'bufferBehind=' + bufferBehind,
|
|
'overflow=' + overflow);
|
|
|
|
await this.playerInterface_.mediaSourceEngine.remove(mediaState.type,
|
|
startTime, startTime + overflow);
|
|
|
|
this.destroyer_.ensureNotDestroyed();
|
|
shaka.log.v1(logPrefix, 'evicted ' + overflow + ' seconds');
|
|
}
|
|
|
|
|
|
/**
|
|
* @param {shaka.media.StreamingEngine.MediaState_} mediaState
|
|
* @return {boolean}
|
|
* @private
|
|
*/
|
|
static isEmbeddedText_(mediaState) {
|
|
const MimeUtils = shaka.util.MimeUtils;
|
|
return mediaState &&
|
|
mediaState.type == shaka.util.ManifestParserUtils.ContentType.TEXT &&
|
|
mediaState.stream.mimeType == MimeUtils.CLOSED_CAPTION_MIMETYPE;
|
|
}
|
|
|
|
|
|
/**
|
|
* Fetches the given segment.
|
|
*
|
|
* @param {!shaka.media.StreamingEngine.MediaState_} mediaState
|
|
* @param {(!shaka.media.InitSegmentReference|!shaka.media.SegmentReference)}
|
|
* reference
|
|
*
|
|
* @return {!Promise.<BufferSource>}
|
|
* @private
|
|
*/
|
|
async fetch_(mediaState, reference) {
|
|
const requestType = shaka.net.NetworkingEngine.RequestType.SEGMENT;
|
|
|
|
const request = shaka.util.Networking.createSegmentRequest(
|
|
reference.getUris(),
|
|
reference.startByte,
|
|
reference.endByte,
|
|
this.config_.retryParameters);
|
|
|
|
shaka.log.v2('fetching: reference=', reference);
|
|
|
|
const op = this.playerInterface_.netEngine.request(requestType, request);
|
|
mediaState.operation = op;
|
|
const response = await op.promise;
|
|
mediaState.operation = null;
|
|
return response.data;
|
|
}
|
|
|
|
|
|
/**
|
|
* Clears the buffer and schedules another update.
|
|
* The optional parameter safeMargin allows to retain a certain amount
|
|
* of buffer, which can help avoiding rebuffering events.
|
|
* The value of the safe margin should be provided by the ABR manager.
|
|
*
|
|
* @param {!shaka.media.StreamingEngine.MediaState_} mediaState
|
|
* @param {boolean} flush
|
|
* @param {number} safeMargin
|
|
* @private
|
|
*/
|
|
async clearBuffer_(mediaState, flush, safeMargin) {
|
|
const logPrefix = shaka.media.StreamingEngine.logPrefix_(mediaState);
|
|
|
|
goog.asserts.assert(
|
|
!mediaState.performingUpdate && (mediaState.updateTimer == null),
|
|
logPrefix + ' unexpected call to clearBuffer_()');
|
|
|
|
mediaState.waitingToClearBuffer = false;
|
|
mediaState.waitingToFlushBuffer = false;
|
|
mediaState.clearBufferSafeMargin = 0;
|
|
mediaState.clearingBuffer = true;
|
|
|
|
shaka.log.debug(logPrefix, 'clearing buffer');
|
|
|
|
if (safeMargin) {
|
|
const presentationTime = this.playerInterface_.getPresentationTime();
|
|
const duration = this.playerInterface_.mediaSourceEngine.getDuration();
|
|
await this.playerInterface_.mediaSourceEngine.remove(
|
|
mediaState.type, presentationTime + safeMargin, duration);
|
|
} else {
|
|
await this.playerInterface_.mediaSourceEngine.clear(mediaState.type);
|
|
this.destroyer_.ensureNotDestroyed();
|
|
|
|
if (flush) {
|
|
await this.playerInterface_.mediaSourceEngine.flush(
|
|
mediaState.type);
|
|
}
|
|
}
|
|
this.destroyer_.ensureNotDestroyed();
|
|
|
|
shaka.log.debug(logPrefix, 'cleared buffer');
|
|
mediaState.lastStream = null;
|
|
mediaState.lastSegmentReference = null;
|
|
mediaState.clearingBuffer = false;
|
|
mediaState.endOfStream = false;
|
|
this.scheduleUpdate_(mediaState, 0);
|
|
}
|
|
|
|
|
|
/**
|
|
* Schedules |mediaState|'s next update.
|
|
*
|
|
* @param {!shaka.media.StreamingEngine.MediaState_} mediaState
|
|
* @param {number} delay The delay in seconds.
|
|
* @private
|
|
*/
|
|
scheduleUpdate_(mediaState, delay) {
|
|
const logPrefix = shaka.media.StreamingEngine.logPrefix_(mediaState);
|
|
shaka.log.v2(logPrefix, 'updating in ' + delay + ' seconds');
|
|
goog.asserts.assert(mediaState.updateTimer == null,
|
|
logPrefix + ' did not expect update to be scheduled');
|
|
|
|
mediaState.updateTimer = new shaka.util.DelayedTick(async () => {
|
|
try {
|
|
await this.onUpdate_(mediaState);
|
|
} catch (error) {
|
|
if (this.playerInterface_) {
|
|
this.playerInterface_.onError(error);
|
|
}
|
|
}
|
|
}).tickAfter(delay);
|
|
}
|
|
|
|
|
|
/**
|
|
* If |mediaState| is scheduled to update, stop it.
|
|
*
|
|
* @param {shaka.media.StreamingEngine.MediaState_} mediaState
|
|
* @private
|
|
*/
|
|
cancelUpdate_(mediaState) {
|
|
if (mediaState.updateTimer == null) {
|
|
return;
|
|
}
|
|
|
|
mediaState.updateTimer.stop();
|
|
mediaState.updateTimer = null;
|
|
}
|
|
|
|
|
|
/**
|
|
* Handle streaming errors by delaying, then notifying the application by
|
|
* error callback and by streaming failure callback.
|
|
*
|
|
* @param {!shaka.util.Error} error
|
|
* @private
|
|
*/
|
|
async handleStreamingError_(error) {
|
|
// If we invoke the callback right away, the application could trigger a
|
|
// rapid retry cycle that could be very unkind to the server. Instead,
|
|
// use the backoff system to delay and backoff the error handling.
|
|
await this.failureCallbackBackoff_.attempt();
|
|
this.destroyer_.ensureNotDestroyed();
|
|
|
|
// First fire an error event.
|
|
this.playerInterface_.onError(error);
|
|
|
|
// If the error was not handled by the application, call the failure
|
|
// callback.
|
|
if (!error.handled) {
|
|
this.config_.failureCallback(error);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* @param {shaka.media.StreamingEngine.MediaState_} mediaState
|
|
* @return {string} A log prefix of the form ($CONTENT_TYPE:$STREAM_ID), e.g.,
|
|
* "(audio:5)" or "(video:hd)".
|
|
* @private
|
|
*/
|
|
static logPrefix_(mediaState) {
|
|
return '(' + mediaState.type + ':' + mediaState.stream.id + ')';
|
|
}
|
|
};
|
|
|
|
|
|
/**
|
|
* @typedef {{
|
|
* getPresentationTime: function():number,
|
|
* getBandwidthEstimate: function():number,
|
|
* mediaSourceEngine: !shaka.media.MediaSourceEngine,
|
|
* netEngine: shaka.net.NetworkingEngine,
|
|
* onError: function(!shaka.util.Error),
|
|
* onEvent: function(!Event),
|
|
* onManifestUpdate: function(),
|
|
* onSegmentAppended: function()
|
|
* }}
|
|
*
|
|
* @property {function():number} getPresentationTime
|
|
* Get the position in the presentation (in seconds) of the content that the
|
|
* viewer is seeing on screen right now.
|
|
* @property {function():number} getBandwidthEstimate
|
|
* Get the estimated bandwidth in bits per second.
|
|
* @property {!shaka.media.MediaSourceEngine} mediaSourceEngine
|
|
* The MediaSourceEngine. The caller retains ownership.
|
|
* @property {shaka.net.NetworkingEngine} netEngine
|
|
* The NetworkingEngine instance to use. The caller retains ownership.
|
|
* @property {function(!shaka.util.Error)} onError
|
|
* Called when an error occurs. If the error is recoverable (see
|
|
* {@link shaka.util.Error}) then the caller may invoke either
|
|
* StreamingEngine.switch*() or StreamingEngine.seeked() to attempt recovery.
|
|
* @property {function(!Event)} onEvent
|
|
* Called when an event occurs that should be sent to the app.
|
|
* @property {function()} onManifestUpdate
|
|
* Called when an embedded 'emsg' box should trigger a manifest update.
|
|
* @property {function()} onSegmentAppended
|
|
* Called after a segment is successfully appended to a MediaSource.
|
|
*/
|
|
shaka.media.StreamingEngine.PlayerInterface;
|
|
|
|
|
|
/**
|
|
* @typedef {{
|
|
* type: shaka.util.ManifestParserUtils.ContentType,
|
|
* stream: shaka.extern.Stream,
|
|
* lastStream: ?shaka.extern.Stream,
|
|
* segmentIterator: shaka.media.SegmentIterator,
|
|
* lastSegmentReference: shaka.media.SegmentReference,
|
|
* lastInitSegmentReference: shaka.media.InitSegmentReference,
|
|
* lastTimestampOffset: ?number,
|
|
* lastAppendWindowStart: ?number,
|
|
* lastAppendWindowEnd: ?number,
|
|
* restoreStreamAfterTrickPlay: ?shaka.extern.Stream,
|
|
* endOfStream: boolean,
|
|
* performingUpdate: boolean,
|
|
* updateTimer: shaka.util.DelayedTick,
|
|
* waitingToClearBuffer: boolean,
|
|
* waitingToFlushBuffer: boolean,
|
|
* clearBufferSafeMargin: number,
|
|
* clearingBuffer: boolean,
|
|
* recovering: boolean,
|
|
* hasError: boolean,
|
|
* operation: shaka.net.NetworkingEngine.PendingRequest
|
|
* }}
|
|
*
|
|
* @description
|
|
* Contains the state of a logical stream, i.e., a sequence of segmented data
|
|
* for a particular content type. At any given time there is a Stream object
|
|
* associated with the state of the logical stream.
|
|
*
|
|
* @property {shaka.util.ManifestParserUtils.ContentType} type
|
|
* The stream's content type, e.g., 'audio', 'video', or 'text'.
|
|
* @property {shaka.extern.Stream} stream
|
|
* The current Stream.
|
|
* @property {?shaka.extern.Stream} lastStream
|
|
* The Stream of the last segment that was appended.
|
|
* @property {shaka.media.SegmentIndexIterator} segmentIterator
|
|
* An iterator through the segments of |stream|.
|
|
* @property {shaka.media.SegmentReference} lastSegmentReference
|
|
* The SegmentReference of the last segment that was appended.
|
|
* @property {shaka.media.InitSegmentReference} lastInitSegmentReference
|
|
* The InitSegmentReference of the last init segment that was appended.
|
|
* @property {?number} lastTimestampOffset
|
|
* The last timestamp offset given to MediaSourceEngine for this type.
|
|
* @property {?number} lastAppendWindowStart
|
|
* The last append window start given to MediaSourceEngine for this type.
|
|
* @property {?number} lastAppendWindowEnd
|
|
* The last append window end given to MediaSourceEngine for this type.
|
|
* @property {?shaka.extern.Stream} restoreStreamAfterTrickPlay
|
|
* The Stream to restore after trick play mode is turned off.
|
|
* @property {boolean} endOfStream
|
|
* True indicates that the end of the buffer has hit the end of the
|
|
* presentation.
|
|
* @property {boolean} performingUpdate
|
|
* True indicates that an update is in progress.
|
|
* @property {shaka.util.DelayedTick} updateTimer
|
|
* A timer used to update the media state.
|
|
* @property {boolean} waitingToClearBuffer
|
|
* True indicates that the buffer must be cleared after the current update
|
|
* finishes.
|
|
* @property {boolean} waitingToFlushBuffer
|
|
* True indicates that the buffer must be flushed after it is cleared.
|
|
* @property {number} clearBufferSafeMargin
|
|
* The amount of buffer to retain when clearing the buffer after the update.
|
|
* @property {boolean} clearingBuffer
|
|
* True indicates that the buffer is being cleared.
|
|
* @property {boolean} recovering
|
|
* True indicates that the last segment was not appended because it could not
|
|
* fit in the buffer.
|
|
* @property {boolean} hasError
|
|
* True indicates that the stream has encountered an error and has stopped
|
|
* updating.
|
|
* @property {shaka.net.NetworkingEngine.PendingRequest} operation
|
|
* Operation with the number of bytes to be downloaded.
|
|
*/
|
|
shaka.media.StreamingEngine.MediaState_;
|
|
|
|
|
|
/**
|
|
* The fudge factor for appendWindowStart. By adjusting the window backward, we
|
|
* avoid rounding errors that could cause us to remove the keyframe at the start
|
|
* of the Period.
|
|
*
|
|
* NOTE: This was increased as part of the solution to
|
|
* https://github.com/google/shaka-player/issues/1281
|
|
*
|
|
* @const {number}
|
|
* @private
|
|
*/
|
|
shaka.media.StreamingEngine.APPEND_WINDOW_START_FUDGE_ = 0.1;
|
|
|
|
|
|
/**
|
|
* The fudge factor for appendWindowEnd. By adjusting the window backward, we
|
|
* avoid rounding errors that could cause us to remove the last few samples of
|
|
* the Period. This rounding error could then create an artificial gap and a
|
|
* stutter when the gap-jumping logic takes over.
|
|
*
|
|
* https://github.com/google/shaka-player/issues/1597
|
|
*
|
|
* @const {number}
|
|
* @private
|
|
*/
|
|
shaka.media.StreamingEngine.APPEND_WINDOW_END_FUDGE_ = 0.01;
|
|
|
|
|
|
/**
|
|
* The maximum number of segments by which a stream can get ahead of other
|
|
* streams.
|
|
*
|
|
* Introduced to keep StreamingEngine from letting one media type get too far
|
|
* ahead of another. For example, audio segments are typically much smaller
|
|
* than video segments, so in the time it takes to fetch one video segment, we
|
|
* could fetch many audio segments. This doesn't help with buffering, though,
|
|
* since the intersection of the two buffered ranges is what counts.
|
|
*
|
|
* @const {number}
|
|
* @private
|
|
*/
|
|
shaka.media.StreamingEngine.MAX_RUN_AHEAD_SEGMENTS_ = 1;
|