shaka-player
Version:
DASH/EME video player library
367 lines (332 loc) • 13.7 kB
JavaScript
/**
* @license
* Copyright 2016 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
goog.provide('shaka.util.PlayerConfiguration');
goog.require('shaka.abr.SimpleAbrManager');
goog.require('shaka.util.ConfigUtils');
// TODO(vaage): Many times in our configs, we need to create an empty
// implementation of a method, but to avoid closure from removing unused
// parameters (and breaking our merge config code) we need to use each
// parameter. Is there a better solution to this problem than what we are
// doing now?
//
// NOTE: Chrome App Content Security Policy prohibits usage of new Function()
/**
* @final
* @export
*/
shaka.util.PlayerConfiguration = class {
/** @return {shaka.extern.PlayerConfiguration} */
static createDefault() {
// This is a relatively safe default, since 3G cell connections
// are faster than this. For slower connections, such as 2G,
// the default estimate may be too high.
let bandwidthEstimate = 500e3; // 500kbps
let abrMaxHeight = Infinity;
// Some browsers implement the Network Information API, which allows
// retrieving information about a user's network connection.
if (navigator.connection) {
// If it's available, get the bandwidth estimate from the browser (in
// megabits per second) and use it as defaultBandwidthEstimate.
// Tizen 3 has NetworkInformation, but not the downlink attribute.
if (navigator.connection.downlink) {
bandwidthEstimate = navigator.connection.downlink * 1e6;
}
// TODO: Move this into AbrManager, where changes to the estimate can be
// observed and absorbed.
// If the user has checked a box in the browser to ask it to use less
// data, the browser will expose this intent via connection.saveData.
// When that is true, we will default the max ABR height to 360p. Apps
// can override this if they wish.
//
// The decision to use 360p was somewhat arbitrary. We needed a default
// limit, and rather than restrict to a certain bandwidth, we decided to
// restrict resolution. This will implicitly restrict bandwidth and
// therefore save data. We (Shaka+Chrome) judged that:
// - HD would be inappropriate
// - If a user is asking their browser to save data, 360p it reasonable
// - 360p would not look terrible on small mobile device screen
// We also found that:
// - YouTube's website on mobile defaults to 360p (as of 2018)
// - iPhone 6, in portrait mode, has a physical resolution big enough
// for 360p widescreen, but a little smaller than 480p widescreen
// (https://apple.co/2yze4es)
// If the content's lowest resolution is above 360p, AbrManager will use
// the lowest resolution.
if (navigator.connection.saveData) {
abrMaxHeight = 360;
}
}
const drm = {
retryParameters: shaka.net.NetworkingEngine.defaultRetryParameters(),
// These will all be verified by special cases in mergeConfigObjects_():
servers: {}, // key is arbitrary key system ID, value must be string
clearKeys: {}, // key is arbitrary key system ID, value must be string
advanced: {}, // key is arbitrary key system ID, value is a record type
delayLicenseRequestUntilPlayed: false,
initDataTransform: shaka.media.DrmEngine.defaultInitDataTransform,
fairPlayTransform: true,
updateExpirationTime: 1,
};
const manifest = {
retryParameters: shaka.net.NetworkingEngine.defaultRetryParameters(),
availabilityWindowOverride: NaN,
disableAudio: false,
disableVideo: false,
disableText: false,
dash: {
// Reference node to keep closure from removing it.
// If the argument is removed, it breaks our function length check
// in mergeConfigObjects_().
customScheme: (node) => {
if (node) return null;
},
clockSyncUri: '',
ignoreDrmInfo: false,
xlinkFailGracefully: false,
defaultPresentationDelay: 10,
ignoreMinBufferTime: false,
autoCorrectDrift: true,
ignoreSuggestedPresentationDelay: false,
ignoreEmptyAdaptationSet: false,
},
hls: {
ignoreTextStreamFailures: false,
useFullSegmentsForStartTime: false,
},
};
const streaming = {
retryParameters: shaka.net.NetworkingEngine.defaultRetryParameters(),
// Need some operation in the callback or else closure may remove calls
// to the function as it would be a no-op. The operation can't just be a
// log message, because those are stripped in the compiled build.
failureCallback: (error) => {
shaka.log.error('Unhandled streaming error', error);
return [error];
},
rebufferingGoal: 2,
bufferingGoal: 10,
bufferBehind: 30,
ignoreTextStreamFailures: false,
alwaysStreamText: false,
startAtSegmentBoundary: false,
smallGapLimit: 0.5,
jumpLargeGaps: false,
durationBackoff: 1,
forceTransmuxTS: false,
// Offset by 5 seconds since Chromecast takes a few seconds to start
// playing after a seek, even when buffered.
safeSeekOffset: 5,
stallEnabled: true,
stallThreshold: 1 /* seconds */,
stallSkip: 0.1 /* seconds */,
useNativeHlsOnSafari: true,
};
// WebOS, Tizen, and Chromecast have long hardware pipelines that respond
// slowly to seeking. Therefore we should not seek when we detect a stall
// on one of these platforms. Instead, default stallSkip to 0 to force the
// stall detector to pause and play instead.
if (shaka.util.Platform.isWebOS() ||
shaka.util.Platform.isTizen() ||
shaka.util.Platform.isChromecast()) {
streaming.stallSkip = 0;
}
const offline = {
// We need to set this to a throw-away implementation for now as our
// default implementation will need to reference other fields in the
// config. We will set it to our intended implementation after we have
// the top-level object created.
// eslint-disable-next-line require-await
trackSelectionCallback: async (tracks) => tracks,
// Need some operation in the callback or else closure may remove calls
// to the function as it would be a no-op. The operation can't just be a
// log message, because those are stripped in the compiled build.
progressCallback: (content, progress) => {
return [content, progress];
},
// By default we use persistent licenses as forces errors to surface if
// a platform does not support offline licenses rather than causing
// unexpected behaviours when someone tries to plays downloaded content
// without a persistent license.
usePersistentLicense: true,
};
const abr = {
enabled: true,
defaultBandwidthEstimate: bandwidthEstimate,
switchInterval: 8,
bandwidthUpgradeTarget: 0.85,
bandwidthDowngradeTarget: 0.95,
restrictions: {
minWidth: 0,
maxWidth: Infinity,
minHeight: 0,
maxHeight: abrMaxHeight,
minPixels: 0,
maxPixels: Infinity,
minFrameRate: 0,
maxFrameRate: Infinity,
minBandwidth: 0,
maxBandwidth: Infinity,
},
};
/** @type {shaka.extern.PlayerConfiguration} */
const config = {
drm: drm,
manifest: manifest,
streaming: streaming,
offline: offline,
abrFactory: shaka.abr.SimpleAbrManager,
abr: abr,
preferredAudioLanguage: '',
preferredTextLanguage: '',
preferredVariantRole: '',
preferredTextRole: '',
preferredAudioChannelCount: 2,
restrictions: {
minWidth: 0,
maxWidth: Infinity,
minHeight: 0,
maxHeight: Infinity,
minPixels: 0,
maxPixels: Infinity,
minFrameRate: 0,
maxFrameRate: Infinity,
minBandwidth: 0,
maxBandwidth: Infinity,
},
playRangeStart: 0,
playRangeEnd: Infinity,
textDisplayFactory: () => null,
};
// Add this callback so that we can reference the preferred audio language
// through the config object so that if it gets updated, we have the
// updated value.
// eslint-disable-next-line require-await
offline.trackSelectionCallback = async (tracks) => {
return shaka.util.PlayerConfiguration.defaultTrackSelect(
tracks, config.preferredAudioLanguage);
};
return config;
}
/**
* Merges the given configuration changes into the given destination. This
* uses the default Player configurations as the template.
*
* @param {shaka.extern.PlayerConfiguration} destination
* @param {!Object} updates
* @param {shaka.extern.PlayerConfiguration=} template
* @return {boolean}
* @export
*/
static mergeConfigObjects(destination, updates, template) {
const overrides = {
'.drm.servers': '',
'.drm.clearKeys': '',
'.drm.advanced': {
distinctiveIdentifierRequired: false,
persistentStateRequired: false,
videoRobustness: '',
audioRobustness: '',
serverCertificate: new Uint8Array(0),
individualizationServer: '',
},
};
return shaka.util.ConfigUtils.mergeConfigObjects(
destination, updates,
template || shaka.util.PlayerConfiguration.createDefault(), overrides,
'');
}
/**
* @param {!Array.<shaka.extern.Track>} tracks
* @param {string} preferredAudioLanguage
* @return {!Array.<shaka.extern.Track>}
*/
static defaultTrackSelect(tracks, preferredAudioLanguage) {
const ContentType = shaka.util.ManifestParserUtils.ContentType;
const LanguageUtils = shaka.util.LanguageUtils;
/** @type {!Array.<shaka.extern.Track>} */
const allVariants = tracks.filter((track) => track.type == 'variant');
/** @type {!Array.<shaka.extern.Track>} */
let selectedVariants = [];
// Find the locale that best matches our preferred audio locale.
const closestLocale = LanguageUtils.findClosestLocale(
preferredAudioLanguage,
allVariants.map((variant) => variant.language));
// If we found a locale that was close to our preference, then only use
// variants that use that locale.
if (closestLocale) {
selectedVariants = allVariants.filter((variant) => {
const locale = LanguageUtils.normalize(variant.language);
return locale == closestLocale;
});
}
// If we failed to get a language match, go with primary.
if (selectedVariants.length == 0) {
selectedVariants = allVariants.filter((variant) => {
return variant.primary;
});
}
// Otherwise, there is no good way to choose the language, so we don't
// choose a language at all.
if (selectedVariants.length == 0) {
// Issue a warning, but only if the content has multiple languages.
// Otherwise, this warning would just be noise.
const languages = new Set(allVariants.map((track) => {
return track.language;
}));
if (languages.size > 1) {
shaka.log.warning('Could not choose a good audio track based on ' +
'language preferences or primary tracks. An ' +
'arbitrary language will be stored!');
}
// Default back to all variants.
selectedVariants = allVariants;
}
// From previously selected variants, choose the SD ones (height <= 480).
const tracksByHeight = selectedVariants.filter((track) => {
return track.height && track.height <= 480;
});
// If variants don't have video or no video with height <= 480 was
// found, proceed with the previously selected tracks.
if (tracksByHeight.length) {
// Sort by resolution, then select all variants which match the height
// of the highest SD res. There may be multiple audio bitrates for the
// same video resolution.
tracksByHeight.sort((a, b) => b.height - a.height);
selectedVariants = tracksByHeight.filter((track) => {
return track.height == tracksByHeight[0].height;
});
}
/** @type {!Array.<shaka.extern.Track>} */
const selectedTracks = [];
// If there are multiple matches at different audio bitrates, select the
// middle bandwidth one.
if (selectedVariants.length) {
const middleIndex = Math.floor(selectedVariants.length / 2);
selectedVariants.sort((a, b) => a.bandwidth - b.bandwidth);
selectedTracks.push(selectedVariants[middleIndex]);
}
// Since this default callback is used primarily by our own demo app and by
// app developers who haven't thought about which tracks they want, we
// should select all text tracks, regardless of language. This makes for a
// better demo for us, and does not rely on user preferences for the
// unconfigured app.
for (const track of tracks) {
if (track.type == ContentType.TEXT) { selectedTracks.push(track); }
}
return selectedTracks;
}
};