Files
shaka-player/lib/util/stream_utils.js
T
Joey Parrish 562a2d567b chore: Strictly require jsdoc
This enables the eslint rule requiring jsdocs on all class
declarations, function declarations, and methods.

Unfortunately, there are two problems with this:

1. We don't use class _declarations_, we use class _expressions_,
which are not covered by this rule.  So it does not enforce jsdoc at
the class level.
2. We tend to document a class at the class-level, rather than at the
constructor.  But a constructor counts as a method for eslint, so it
requires docs on the constructor.  There is no way to configure it to
make an exception for trivial constructors.

So for all trivial (no-argument) constructors, we add empty jsdocs:
  /** */
  constructor() {

This was quicker and easier than setting up some alternative plugin in
eslint to make an exception for us.

The good news is that this rule caught several undocumented parameters
and places where the jsdoc comment was malformed.  So fixing those
also improves the compiler's ability to enforce types.

Change-Id: Icbc46ed690c94e53d354648a883119524f8fca45
2021-01-09 02:00:31 +00:00

811 lines
23 KiB
JavaScript

/*! @license
* Shaka Player
* Copyright 2016 Google LLC
* SPDX-License-Identifier: Apache-2.0
*/
goog.provide('shaka.util.StreamUtils');
goog.require('goog.asserts');
goog.require('shaka.log');
goog.require('shaka.media.DrmEngine');
goog.require('shaka.media.MediaSourceEngine');
goog.require('shaka.text.TextEngine');
goog.require('shaka.util.Functional');
goog.require('shaka.util.LanguageUtils');
goog.require('shaka.util.ManifestParserUtils');
goog.require('shaka.util.MimeUtils');
goog.require('shaka.util.MultiMap');
/**
* @summary A set of utility functions for dealing with Streams and Manifests.
*/
shaka.util.StreamUtils = class {
/**
* In case of multiple usable codecs, choose one based on lowest average
* bandwidth and filter out the rest.
* Also filters out variants that have too many audio channels.
* @param {!shaka.extern.Manifest} manifest
* @param {number} preferredAudioChannelCount
*/
static chooseCodecsAndFilterManifest(manifest, preferredAudioChannelCount) {
const MimeUtils = shaka.util.MimeUtils;
// To start, consider a subset of variants based on audio channel
// preferences.
// For some content (#1013), surround-sound variants will use a different
// codec than stereo variants, so it is important to choose codecs **after**
// considering the audio channel config.
const variants = shaka.util.StreamUtils.filterVariantsByAudioChannelCount(
manifest.variants, preferredAudioChannelCount);
/**
* @param {!shaka.extern.Variant} variant
* @return {string}
*/
function variantCodecs(variant) {
// Only consider the base of the codec string. For example, these should
// both be considered the same codec: avc1.42c01e, avc1.4d401f
let baseVideoCodec = '';
if (variant.video) {
baseVideoCodec = MimeUtils.getCodecBase(variant.video.codecs);
}
let baseAudioCodec = '';
if (variant.audio) {
baseAudioCodec = MimeUtils.getCodecBase(variant.audio.codecs);
}
return baseVideoCodec + '-' + baseAudioCodec;
}
// Now organize variants into buckets by codecs.
/** @type {!shaka.util.MultiMap.<shaka.extern.Variant>} */
const variantsByCodecs = new shaka.util.MultiMap();
for (const variant of variants) {
const group = variantCodecs(variant);
variantsByCodecs.push(group, variant);
}
// Compute the average bandwidth for each group of variants.
// Choose the lowest-bandwidth codecs.
let bestCodecs = null;
let lowestAverageBandwidth = Infinity;
variantsByCodecs.forEach((codecs, variants) => {
let sum = 0;
let num = 0;
for (const variant of variants) {
sum += variant.bandwidth || 0;
++num;
}
const averageBandwidth = sum / num;
shaka.log.debug('codecs', codecs, 'avg bandwidth', averageBandwidth);
if (averageBandwidth < lowestAverageBandwidth) {
bestCodecs = codecs;
lowestAverageBandwidth = averageBandwidth;
}
});
goog.asserts.assert(bestCodecs != null, 'Should have chosen codecs!');
goog.asserts.assert(!isNaN(lowestAverageBandwidth),
'Bandwidth should be a number!');
// Filter out any variants that don't match, forcing AbrManager to choose
// from the most efficient variants possible.
manifest.variants = manifest.variants.filter((variant) => {
const codecs = variantCodecs(variant);
if (codecs == bestCodecs) {
return true;
}
shaka.log.debug('Dropping Variant (better codec available)', variant);
return false;
});
}
/**
* @param {shaka.extern.Variant} variant
* @param {shaka.extern.Restrictions} restrictions
* Configured restrictions from the user.
* @param {{width: number, height: number}} maxHwRes
* The maximum resolution the hardware can handle.
* This is applied separately from user restrictions because the setting
* should not be easily replaced by the user's configuration.
* @return {boolean}
*/
static meetsRestrictions(variant, restrictions, maxHwRes) {
/** @type {function(number, number, number):boolean} */
const inRange = (x, min, max) => {
return x >= min && x <= max;
};
const video = variant.video;
// |video.width| and |video.height| can be undefined, which breaks
// the math, so make sure they are there first.
if (video && video.width && video.height) {
if (!inRange(video.width,
restrictions.minWidth,
Math.min(restrictions.maxWidth, maxHwRes.width))) {
return false;
}
if (!inRange(video.height,
restrictions.minHeight,
Math.min(restrictions.maxHeight, maxHwRes.height))) {
return false;
}
if (!inRange(video.width * video.height,
restrictions.minPixels,
restrictions.maxPixels)) {
return false;
}
}
// |variant.frameRate| can be undefined, which breaks
// the math, so make sure they are there first.
if (variant && variant.video && variant.video.frameRate) {
if (!inRange(variant.video.frameRate,
restrictions.minFrameRate,
restrictions.maxFrameRate)) {
return false;
}
}
if (!inRange(variant.bandwidth,
restrictions.minBandwidth,
restrictions.maxBandwidth)) {
return false;
}
return true;
}
/**
* @param {!Array.<shaka.extern.Variant>} variants
* @param {shaka.extern.Restrictions} restrictions
* @param {{width: number, height: number}} maxHwRes
* @return {boolean} Whether the tracks changed.
*/
static applyRestrictions(variants, restrictions, maxHwRes) {
let tracksChanged = false;
for (const variant of variants) {
const originalAllowed = variant.allowedByApplication;
variant.allowedByApplication = shaka.util.StreamUtils.meetsRestrictions(
variant, restrictions, maxHwRes);
if (originalAllowed != variant.allowedByApplication) {
tracksChanged = true;
}
}
return tracksChanged;
}
/**
* Alters the given Manifest to filter out any unplayable streams.
*
* @param {shaka.media.DrmEngine} drmEngine
* @param {?shaka.extern.Variant} currentVariant
* @param {shaka.extern.Manifest} manifest
*/
static filterManifest(drmEngine, currentVariant, manifest) {
const StreamUtils = shaka.util.StreamUtils;
// Filter variants.
manifest.variants = manifest.variants.filter((variant) => {
if (drmEngine && drmEngine.initialized()) {
if (!drmEngine.supportsVariant(variant)) {
shaka.log.debug('Dropping variant - not compatible with key system',
variant);
return false;
}
}
const audio = variant.audio;
const video = variant.video;
if (audio && !shaka.media.MediaSourceEngine.isStreamSupported(audio)) {
shaka.log.debug('Dropping variant - audio not compatible with platform',
StreamUtils.getStreamSummaryString_(audio));
return false;
}
if (video && !shaka.media.MediaSourceEngine.isStreamSupported(video)) {
shaka.log.debug('Dropping variant - video not compatible with platform',
StreamUtils.getStreamSummaryString_(video));
return false;
}
if (audio && currentVariant && currentVariant.audio) {
if (!StreamUtils.areStreamsCompatible_(audio, currentVariant.audio)) {
shaka.log.debug('Droping variant - not compatible with active audio',
'active audio',
StreamUtils.getStreamSummaryString_(currentVariant.audio),
'variant.audio',
StreamUtils.getStreamSummaryString_(audio));
return false;
}
}
if (video && currentVariant && currentVariant.video) {
if (!StreamUtils.areStreamsCompatible_(video, currentVariant.video)) {
shaka.log.debug('Droping variant - not compatible with active video',
'active video',
StreamUtils.getStreamSummaryString_(currentVariant.video),
'variant.video',
StreamUtils.getStreamSummaryString_(video));
return false;
}
}
return true;
});
// Filter text streams.
manifest.textStreams = manifest.textStreams.filter((stream) => {
const fullMimeType = shaka.util.MimeUtils.getFullType(
stream.mimeType, stream.codecs);
const keep = shaka.text.TextEngine.isTypeSupported(fullMimeType);
if (!keep) {
shaka.log.debug('Dropping text stream. Is not supported by the ' +
'platform.', stream);
}
return keep;
});
}
/**
* @param {shaka.extern.Stream} s0
* @param {shaka.extern.Stream} s1
* @return {boolean}
* @private
*/
static areStreamsCompatible_(s0, s1) {
// Basic mime types and basic codecs need to match.
// For example, we can't adapt between WebM and MP4,
// nor can we adapt between mp4a.* to ec-3.
// We can switch between text types on the fly,
// so don't run this check on text.
if (s0.mimeType != s1.mimeType) {
return false;
}
if (s0.codecs.split('.')[0] != s1.codecs.split('.')[0]) {
return false;
}
return true;
}
/**
* @param {shaka.extern.Variant} variant
* @return {shaka.extern.Track}
*/
static variantToTrack(variant) {
/** @type {?shaka.extern.Stream} */
const audio = variant.audio;
/** @type {?shaka.extern.Stream} */
const video = variant.video;
/** @type {?string} */
const audioCodec = audio ? audio.codecs : null;
/** @type {?string} */
const videoCodec = video ? video.codecs : null;
/** @type {!Array.<string>} */
const codecs = [];
if (videoCodec) {
codecs.push(videoCodec);
}
if (audioCodec) {
codecs.push(audioCodec);
}
/** @type {!Array.<string>} */
const mimeTypes = [];
if (video) {
mimeTypes.push(video.mimeType);
}
if (audio) {
mimeTypes.push(audio.mimeType);
}
/** @type {?string} */
const mimeType = mimeTypes[0] || null;
/** @type {!Array.<string>} */
const kinds = [];
if (audio) {
kinds.push(audio.kind);
}
if (video) {
kinds.push(video.kind);
}
/** @type {?string} */
const kind = kinds[0] || null;
/** @type {!Set.<string>} */
const roles = new Set();
if (audio) {
for (const role of audio.roles) {
roles.add(role);
}
}
if (video) {
for (const role of video.roles) {
roles.add(role);
}
}
/** @type {shaka.extern.Track} */
const track = {
id: variant.id,
active: false,
type: 'variant',
bandwidth: variant.bandwidth,
language: variant.language,
label: null,
kind: kind,
width: null,
height: null,
frameRate: null,
pixelAspectRatio: null,
mimeType: mimeType,
codecs: codecs.join(', '),
audioCodec: audioCodec,
videoCodec: videoCodec,
primary: variant.primary,
roles: Array.from(roles),
audioRoles: null,
forced: false,
videoId: null,
audioId: null,
channelsCount: null,
audioSamplingRate: null,
audioBandwidth: null,
videoBandwidth: null,
originalVideoId: null,
originalAudioId: null,
originalTextId: null,
};
if (video) {
track.videoId = video.id;
track.originalVideoId = video.originalId;
track.width = video.width || null;
track.height = video.height || null;
track.frameRate = video.frameRate || null;
track.pixelAspectRatio = video.pixelAspectRatio || null;
track.videoBandwidth = video.bandwidth || null;
}
if (audio) {
track.audioId = audio.id;
track.originalAudioId = audio.originalId;
track.channelsCount = audio.channelsCount;
track.audioSamplingRate = audio.audioSamplingRate;
track.audioBandwidth = audio.bandwidth || null;
track.label = audio.label;
track.audioRoles = audio.roles;
}
return track;
}
/**
* @param {shaka.extern.Stream} stream
* @return {shaka.extern.Track}
*/
static textStreamToTrack(stream) {
const ContentType = shaka.util.ManifestParserUtils.ContentType;
/** @type {shaka.extern.Track} */
const track = {
id: stream.id,
active: false,
type: ContentType.TEXT,
bandwidth: 0,
language: stream.language,
label: stream.label,
kind: stream.kind || null,
width: null,
height: null,
frameRate: null,
pixelAspectRatio: null,
mimeType: stream.mimeType,
codecs: stream.codecs || null,
audioCodec: null,
videoCodec: null,
primary: stream.primary,
roles: stream.roles,
audioRoles: null,
forced: stream.forced,
videoId: null,
audioId: null,
channelsCount: null,
audioSamplingRate: null,
audioBandwidth: null,
videoBandwidth: null,
originalVideoId: null,
originalAudioId: null,
originalTextId: stream.originalId,
};
return track;
}
/**
* Generate and return an ID for this track, since the ID field is optional.
*
* @param {TextTrack|AudioTrack} html5Track
* @return {number} The generated ID.
*/
static html5TrackId(html5Track) {
if (!html5Track['__shaka_id']) {
html5Track['__shaka_id'] = shaka.util.StreamUtils.nextTrackId_++;
}
return html5Track['__shaka_id'];
}
/**
* @param {TextTrack} textTrack
* @return {shaka.extern.Track}
*/
static html5TextTrackToTrack(textTrack) {
const CLOSED_CAPTION_MIMETYPE =
shaka.util.MimeUtils.CEA608_CLOSED_CAPTION_MIMETYPE;
const StreamUtils = shaka.util.StreamUtils;
/** @type {shaka.extern.Track} */
const track = StreamUtils.html5TrackToGenericShakaTrack_(textTrack);
track.active = textTrack.mode != 'disabled';
track.type = 'text';
track.originalTextId = textTrack.id;
if (textTrack.kind == 'captions') {
track.mimeType = CLOSED_CAPTION_MIMETYPE;
}
if (textTrack.kind) {
track.roles = [textTrack.kind];
}
if (textTrack.kind == 'forced') {
track.forced = true;
}
return track;
}
/**
* @param {AudioTrack} audioTrack
* @return {shaka.extern.Track}
*/
static html5AudioTrackToTrack(audioTrack) {
const StreamUtils = shaka.util.StreamUtils;
/** @type {shaka.extern.Track} */
const track = StreamUtils.html5TrackToGenericShakaTrack_(audioTrack);
track.active = audioTrack.enabled;
track.type = 'variant';
track.originalAudioId = audioTrack.id;
if (audioTrack.kind == 'main') {
track.primary = true;
}
if (audioTrack.kind) {
track.roles = [audioTrack.kind];
track.audioRoles = [audioTrack.kind];
track.label = audioTrack.label;
}
return track;
}
/**
* Creates a Track object with non-type specific fields filled out. The
* caller is responsible for completing the Track object with any
* type-specific information (audio or text).
*
* @param {TextTrack|AudioTrack} html5Track
* @return {shaka.extern.Track}
* @private
*/
static html5TrackToGenericShakaTrack_(html5Track) {
/** @type {shaka.extern.Track} */
const track = {
id: shaka.util.StreamUtils.html5TrackId(html5Track),
active: false,
type: '',
bandwidth: 0,
language: shaka.util.LanguageUtils.normalize(html5Track.language),
label: html5Track.label,
kind: html5Track.kind,
width: null,
height: null,
frameRate: null,
pixelAspectRatio: null,
mimeType: null,
codecs: null,
audioCodec: null,
videoCodec: null,
primary: false,
roles: [],
forced: false,
audioRoles: null,
videoId: null,
audioId: null,
channelsCount: null,
audioSamplingRate: null,
audioBandwidth: null,
videoBandwidth: null,
originalVideoId: null,
originalAudioId: null,
originalTextId: null,
};
return track;
}
/**
* Determines if the given variant is playable.
* @param {!shaka.extern.Variant} variant
* @return {boolean}
*/
static isPlayable(variant) {
return variant.allowedByApplication && variant.allowedByKeySystem;
}
/**
* Filters out unplayable variants.
* @param {!Array.<!shaka.extern.Variant>} variants
* @return {!Array.<!shaka.extern.Variant>}
*/
static getPlayableVariants(variants) {
return variants.filter((variant) => {
return shaka.util.StreamUtils.isPlayable(variant);
});
}
/**
* Filters variants according to the given audio channel count config.
*
* @param {!Array.<shaka.extern.Variant>} variants
* @param {number} preferredAudioChannelCount
* @return {!Array.<!shaka.extern.Variant>}
*/
static filterVariantsByAudioChannelCount(
variants, preferredAudioChannelCount) {
// Group variants by their audio channel counts.
const variantsWithChannelCounts =
variants.filter((v) => v.audio && v.audio.channelsCount);
/** @type {!Map.<number, !Array.<shaka.extern.Variant>>} */
const variantsByChannelCount = new Map();
for (const variant of variantsWithChannelCounts) {
const count = variant.audio.channelsCount;
goog.asserts.assert(count != null, 'Must have count after filtering!');
if (!variantsByChannelCount.has(count)) {
variantsByChannelCount.set(count, []);
}
variantsByChannelCount.get(count).push(variant);
}
/** @type {!Array.<number>} */
const channelCounts = Array.from(variantsByChannelCount.keys());
// If no variant has audio channel count info, return the original variants.
if (channelCounts.length == 0) {
return variants;
}
// Choose the variants with the largest number of audio channels less than
// or equal to the configured number of audio channels.
const countLessThanOrEqualtoConfig =
channelCounts.filter((count) => count <= preferredAudioChannelCount);
if (countLessThanOrEqualtoConfig.length) {
return variantsByChannelCount.get(
Math.max(...countLessThanOrEqualtoConfig));
}
// If all variants have more audio channels than the config, choose the
// variants with the fewest audio channels.
return variantsByChannelCount.get(Math.min(...channelCounts));
}
/**
* Chooses streams according to the given config.
*
* @param {!Array.<shaka.extern.Stream>} streams
* @param {string} preferredLanguage
* @param {string} preferredRole
* @param {boolean} preferredForced
* @return {!Array.<!shaka.extern.Stream>}
*/
static filterStreamsByLanguageAndRole(
streams, preferredLanguage, preferredRole, preferredForced) {
const LanguageUtils = shaka.util.LanguageUtils;
/** @type {!Array.<!shaka.extern.Stream>} */
let chosen = streams;
// Start with the set of primary streams.
/** @type {!Array.<!shaka.extern.Stream>} */
const primary = streams.filter((stream) => {
return stream.primary;
});
if (primary.length) {
chosen = primary;
}
// Now reduce the set to one language. This covers both arbitrary language
// choice and the reduction of the "primary" stream set to one language.
const firstLanguage = chosen.length ? chosen[0].language : '';
chosen = chosen.filter((stream) => {
return stream.language == firstLanguage;
});
// Find the streams that best match our language preference. This will
// override previous selections.
if (preferredLanguage) {
const closestLocale = LanguageUtils.findClosestLocale(
LanguageUtils.normalize(preferredLanguage),
streams.map((stream) => stream.language));
// Only replace |chosen| if we found a locale that is close to our
// preference.
if (closestLocale) {
chosen = streams.filter((stream) => {
const locale = LanguageUtils.normalize(stream.language);
return locale == closestLocale;
});
}
}
// Filter by forced preference
chosen = chosen.filter((stream) => {
return stream.forced == preferredForced;
});
// Now refine the choice based on role preference.
if (preferredRole) {
const roleMatches = shaka.util.StreamUtils.filterTextStreamsByRole_(
chosen, preferredRole);
if (roleMatches.length) {
return roleMatches;
} else {
shaka.log.warning('No exact match for the text role could be found.');
}
} else {
// Prefer text streams with no roles, if they exist.
const noRoleMatches = chosen.filter((stream) => {
return stream.roles.length == 0;
});
if (noRoleMatches.length) {
return noRoleMatches;
}
}
// Either there was no role preference, or it could not be satisfied.
// Choose an arbitrary role, if there are any, and filter out any other
// roles. This ensures we never adapt between roles.
const allRoles = chosen.map((stream) => {
return stream.roles;
}).reduce(shaka.util.Functional.collapseArrays, []);
if (!allRoles.length) {
return chosen;
}
return shaka.util.StreamUtils.filterTextStreamsByRole_(chosen, allRoles[0]);
}
/**
* Filter text Streams by role.
*
* @param {!Array.<shaka.extern.Stream>} textStreams
* @param {string} preferredRole
* @return {!Array.<shaka.extern.Stream>}
* @private
*/
static filterTextStreamsByRole_(textStreams, preferredRole) {
return textStreams.filter((stream) => {
return stream.roles.includes(preferredRole);
});
}
/**
* Checks if the given stream is an audio stream.
*
* @param {shaka.extern.Stream} stream
* @return {boolean}
*/
static isAudio(stream) {
const ContentType = shaka.util.ManifestParserUtils.ContentType;
return stream.type == ContentType.AUDIO;
}
/**
* Checks if the given stream is a video stream.
*
* @param {shaka.extern.Stream} stream
* @return {boolean}
*/
static isVideo(stream) {
const ContentType = shaka.util.ManifestParserUtils.ContentType;
return stream.type == ContentType.VIDEO;
}
/**
* Get all non-null streams in the variant as an array.
*
* @param {shaka.extern.Variant} variant
* @return {!Array.<shaka.extern.Stream>}
*/
static getVariantStreams(variant) {
const streams = [];
if (variant.audio) {
streams.push(variant.audio);
}
if (variant.video) {
streams.push(variant.video);
}
return streams;
}
/**
* @param {shaka.extern.Stream} stream
* @return {string}
* @private
*/
static getStreamSummaryString_(stream) {
// Accepted parameters for Chromecast can be found (internally) at
// go/cast-mime-params
if (shaka.util.StreamUtils.isAudio(stream)) {
return 'type=audio' +
' codecs=' + stream.codecs +
' bandwidth='+ stream.bandwidth +
' channelsCount=' + stream.channelsCount +
' audioSamplingRate=' + stream.audioSamplingRate;
}
if (shaka.util.StreamUtils.isVideo(stream)) {
return 'type=video' +
' codecs=' + stream.codecs +
' bandwidth=' + stream.bandwidth +
' frameRate=' + stream.frameRate +
' width=' + stream.width +
' height=' + stream.height;
}
return 'unexpected stream type';
}
};
/** @private {number} */
shaka.util.StreamUtils.nextTrackId_ = 0;