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level-controller.js
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level-controller.js
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/*
* Level Controller
*/
import Event from '../events';
import EventHandler from '../event-handler';
import { logger } from '../utils/logger';
import { ErrorTypes, ErrorDetails } from '../errors';
import { isCodecSupportedInMp4 } from '../utils/codecs';
import { addGroupId } from './level-helper';
const { performance } = window;
export default class LevelController extends EventHandler {
constructor (hls) {
super(hls,
Event.MANIFEST_LOADED,
Event.LEVEL_LOADED,
Event.AUDIO_TRACK_SWITCHED,
Event.FRAG_LOADED,
Event.ERROR);
this.canload = false;
this.currentLevelIndex = null;
this.manualLevelIndex = -1;
this.timer = null;
}
onHandlerDestroying () {
this.clearTimer();
this.manualLevelIndex = -1;
}
clearTimer () {
if (this.timer !== null) {
clearTimeout(this.timer);
this.timer = null;
}
}
startLoad () {
let levels = this._levels;
this.canload = true;
this.levelRetryCount = 0;
// clean up live level details to force reload them, and reset load errors
if (levels) {
levels.forEach(level => {
level.loadError = 0;
const levelDetails = level.details;
if (levelDetails && levelDetails.live) {
level.details = undefined;
}
});
}
// speed up live playlist refresh if timer exists
if (this.timer !== null) {
this.loadLevel();
}
}
stopLoad () {
this.canload = false;
}
onManifestLoaded (data) {
let levels = [];
let bitrateStart;
let levelSet = {};
let levelFromSet = null;
let videoCodecFound = false;
let audioCodecFound = false;
let chromeOrFirefox = /chrome|firefox/.test(navigator.userAgent.toLowerCase());
let audioTracks = [];
// regroup redundant levels together
data.levels.forEach(level => {
level.loadError = 0;
level.fragmentError = false;
videoCodecFound = videoCodecFound || !!level.videoCodec;
audioCodecFound = audioCodecFound || !!level.audioCodec || !!(level.attrs && level.attrs.AUDIO);
// erase audio codec info if browser does not support mp4a.40.34.
// demuxer will autodetect codec and fallback to mpeg/audio
if (chromeOrFirefox && level.audioCodec && level.audioCodec.indexOf('mp4a.40.34') !== -1) {
level.audioCodec = undefined;
}
levelFromSet = levelSet[level.bitrate]; // FIXME: we would also have to match the resolution here
if (!levelFromSet) {
level.url = [level.url];
level.urlId = 0;
levelSet[level.bitrate] = level;
levels.push(level);
} else {
levelFromSet.url.push(level.url);
}
if (level.attrs && level.attrs.AUDIO) {
addGroupId(levelFromSet || level, 'audio', level.attrs.AUDIO);
}
if (level.attrs && level.attrs.SUBTITLES) {
addGroupId(levelFromSet || level, 'text', level.attrs.SUBTITLES);
}
});
// remove audio-only level if we also have levels with audio+video codecs signalled
if (videoCodecFound && audioCodecFound) {
levels = levels.filter(({ videoCodec }) => !!videoCodec);
}
// only keep levels with supported audio/video codecs
levels = levels.filter(({ audioCodec, videoCodec }) => {
return (!audioCodec || isCodecSupportedInMp4(audioCodec)) && (!videoCodec || isCodecSupportedInMp4(videoCodec));
});
if (data.audioTracks) {
audioTracks = data.audioTracks.filter(track => !track.audioCodec || isCodecSupportedInMp4(track.audioCodec, 'audio'));
}
if (levels.length > 0) {
// start bitrate is the first bitrate of the manifest
bitrateStart = levels[0].bitrate;
// sort level on bitrate
levels.sort(function (a, b) {
return a.bitrate - b.bitrate;
});
this._levels = levels;
// find index of first level in sorted levels
for (let i = 0; i < levels.length; i++) {
if (levels[i].bitrate === bitrateStart) {
this._firstLevel = i;
logger.log(`manifest loaded,${levels.length} level(s) found, first bitrate:${bitrateStart}`);
break;
}
}
this.hls.trigger(Event.MANIFEST_PARSED, {
levels,
audioTracks,
firstLevel: this._firstLevel,
stats: data.stats,
audio: audioCodecFound,
video: videoCodecFound,
altAudio: audioTracks.length > 0 && videoCodecFound
});
} else {
this.hls.trigger(Event.ERROR, {
type: ErrorTypes.MEDIA_ERROR,
details: ErrorDetails.MANIFEST_INCOMPATIBLE_CODECS_ERROR,
fatal: true,
url: this.hls.url,
reason: 'no level with compatible codecs found in manifest'
});
}
}
get levels () {
return this._levels;
}
get level () {
return this.currentLevelIndex;
}
set level (newLevel) {
let levels = this._levels;
if (levels) {
newLevel = Math.min(newLevel, levels.length - 1);
if (this.currentLevelIndex !== newLevel || !levels[newLevel].details) {
this.setLevelInternal(newLevel);
}
}
}
setLevelInternal (newLevel) {
const levels = this._levels;
const hls = this.hls;
// check if level idx is valid
if (newLevel >= 0 && newLevel < levels.length) {
// stopping live reloading timer if any
this.clearTimer();
if (this.currentLevelIndex !== newLevel) {
logger.log(`switching to level ${newLevel}`);
this.currentLevelIndex = newLevel;
const levelProperties = levels[newLevel];
levelProperties.level = newLevel;
hls.trigger(Event.LEVEL_SWITCHING, levelProperties);
}
const level = levels[newLevel];
const levelDetails = level.details;
// check if we need to load playlist for this level
if (!levelDetails || levelDetails.live) {
// level not retrieved yet, or live playlist we need to (re)load it
let urlId = level.urlId;
hls.trigger(Event.LEVEL_LOADING, { url: level.url[urlId], level: newLevel, id: urlId });
}
} else {
// invalid level id given, trigger error
hls.trigger(Event.ERROR, {
type: ErrorTypes.OTHER_ERROR,
details: ErrorDetails.LEVEL_SWITCH_ERROR,
level: newLevel,
fatal: false,
reason: 'invalid level idx'
});
}
}
get manualLevel () {
return this.manualLevelIndex;
}
set manualLevel (newLevel) {
this.manualLevelIndex = newLevel;
if (this._startLevel === undefined) {
this._startLevel = newLevel;
}
if (newLevel !== -1) {
this.level = newLevel;
}
}
get firstLevel () {
return this._firstLevel;
}
set firstLevel (newLevel) {
this._firstLevel = newLevel;
}
get startLevel () {
// hls.startLevel takes precedence over config.startLevel
// if none of these values are defined, fallback on this._firstLevel (first quality level appearing in variant manifest)
if (this._startLevel === undefined) {
let configStartLevel = this.hls.config.startLevel;
if (configStartLevel !== undefined) {
return configStartLevel;
} else {
return this._firstLevel;
}
} else {
return this._startLevel;
}
}
set startLevel (newLevel) {
this._startLevel = newLevel;
}
onError (data) {
if (data.fatal) {
if (data.type === ErrorTypes.NETWORK_ERROR) {
this.clearTimer();
}
return;
}
let levelError = false, fragmentError = false;
let levelIndex;
// try to recover not fatal errors
switch (data.details) {
case ErrorDetails.FRAG_LOAD_ERROR:
case ErrorDetails.FRAG_LOAD_TIMEOUT:
case ErrorDetails.KEY_LOAD_ERROR:
case ErrorDetails.KEY_LOAD_TIMEOUT:
levelIndex = data.frag.level;
fragmentError = true;
break;
case ErrorDetails.LEVEL_LOAD_ERROR:
case ErrorDetails.LEVEL_LOAD_TIMEOUT:
levelIndex = data.context.level;
levelError = true;
break;
case ErrorDetails.REMUX_ALLOC_ERROR:
levelIndex = data.level;
levelError = true;
break;
}
if (levelIndex !== undefined) {
this.recoverLevel(data, levelIndex, levelError, fragmentError);
}
}
/**
* Switch to a redundant stream if any available.
* If redundant stream is not available, emergency switch down if ABR mode is enabled.
*
* @param {Object} errorEvent
* @param {Number} levelIndex current level index
* @param {Boolean} levelError
* @param {Boolean} fragmentError
*/
// FIXME Find a better abstraction where fragment/level retry management is well decoupled
recoverLevel (errorEvent, levelIndex, levelError, fragmentError) {
let { config } = this.hls;
let { details: errorDetails } = errorEvent;
let level = this._levels[levelIndex];
let redundantLevels, delay, nextLevel;
level.loadError++;
level.fragmentError = fragmentError;
if (levelError) {
if ((this.levelRetryCount + 1) <= config.levelLoadingMaxRetry) {
// exponential backoff capped to max retry timeout
delay = Math.min(Math.pow(2, this.levelRetryCount) * config.levelLoadingRetryDelay, config.levelLoadingMaxRetryTimeout);
// Schedule level reload
this.timer = setTimeout(() => this.loadLevel(), delay);
// boolean used to inform stream controller not to switch back to IDLE on non fatal error
errorEvent.levelRetry = true;
this.levelRetryCount++;
logger.warn(`level controller, ${errorDetails}, retry in ${delay} ms, current retry count is ${this.levelRetryCount}`);
} else {
logger.error(`level controller, cannot recover from ${errorDetails} error`);
this.currentLevelIndex = null;
// stopping live reloading timer if any
this.clearTimer();
// switch error to fatal
errorEvent.fatal = true;
return;
}
}
// Try any redundant streams if available for both errors: level and fragment
// If level.loadError reaches redundantLevels it means that we tried them all, no hope => let's switch down
if (levelError || fragmentError) {
redundantLevels = level.url.length;
if (redundantLevels > 1 && level.loadError < redundantLevels) {
level.urlId = (level.urlId + 1) % redundantLevels;
level.details = undefined;
logger.warn(`level controller, ${errorDetails} for level ${levelIndex}: switching to redundant URL-id ${level.urlId}`);
// console.log('Current audio track group ID:', this.hls.audioTracks[this.hls.audioTrack].groupId);
// console.log('New video quality level audio group id:', level.attrs.AUDIO);
} else {
// Search for available level
if (this.manualLevelIndex === -1) {
// When lowest level has been reached, let's start hunt from the top
nextLevel = (levelIndex === 0) ? this._levels.length - 1 : levelIndex - 1;
logger.warn(`level controller, ${errorDetails}: switch to ${nextLevel}`);
this.hls.nextAutoLevel = this.currentLevelIndex = nextLevel;
} else if (fragmentError) {
// Allow fragment retry as long as configuration allows.
// reset this._level so that another call to set level() will trigger again a frag load
logger.warn(`level controller, ${errorDetails}: reload a fragment`);
this.currentLevelIndex = null;
}
}
}
}
// reset errors on the successful load of a fragment
onFragLoaded ({ frag }) {
if (frag !== undefined && frag.type === 'main') {
const level = this._levels[frag.level];
if (level !== undefined) {
level.fragmentError = false;
level.loadError = 0;
this.levelRetryCount = 0;
}
}
}
onLevelLoaded (data) {
const levelId = data.level;
// only process level loaded events matching with expected level
if (levelId !== this.currentLevelIndex) {
return;
}
const curLevel = this._levels[levelId];
// reset level load error counter on successful level loaded only if there is no issues with fragments
if (!curLevel.fragmentError) {
curLevel.loadError = 0;
this.levelRetryCount = 0;
}
let newDetails = data.details;
// if current playlist is a live playlist, arm a timer to reload it
if (newDetails.live) {
const targetdurationMs = 1000 * (newDetails.averagetargetduration ? newDetails.averagetargetduration : newDetails.targetduration);
let reloadInterval = targetdurationMs,
curDetails = curLevel.details;
if (curDetails && newDetails.endSN === curDetails.endSN) {
// follow HLS Spec, If the client reloads a Playlist file and finds that it has not
// changed then it MUST wait for a period of one-half the target
// duration before retrying.
reloadInterval /= 2;
logger.log('same live playlist, reload twice faster');
}
// decrement reloadInterval with level loading delay
reloadInterval -= performance.now() - data.stats.trequest;
// in any case, don't reload more than half of target duration
reloadInterval = Math.max(targetdurationMs / 2, Math.round(reloadInterval));
logger.log(`live playlist, reload in ${Math.round(reloadInterval)} ms`);
this.timer = setTimeout(() => this.loadLevel(), reloadInterval);
} else {
this.clearTimer();
}
}
onAudioTrackSwitched (data) {
const audioGroupId = this.hls.audioTracks[data.id].groupId;
const currentLevel = this.hls.levels[this.currentLevelIndex];
if (!currentLevel) {
return;
}
if (currentLevel.audioGroupIds) {
const urlId = currentLevel.audioGroupIds.findIndex((groupId) => groupId === audioGroupId);
if (urlId !== currentLevel.urlId) {
currentLevel.urlId = urlId;
this.startLoad();
}
}
}
loadLevel () {
logger.debug('call to loadLevel');
if (this.currentLevelIndex !== null && this.canload) {
const levelObject = this._levels[this.currentLevelIndex];
if (typeof levelObject === 'object' &&
levelObject.url.length > 0) {
const level = this.currentLevelIndex;
const id = levelObject.urlId;
const url = levelObject.url[id];
logger.log(`Attempt loading level index ${level} with URL-id ${id}`);
// console.log('Current audio track group ID:', this.hls.audioTracks[this.hls.audioTrack].groupId);
// console.log('New video quality level audio group id:', levelObject.attrs.AUDIO, level);
this.hls.trigger(Event.LEVEL_LOADING, { url, level, id });
}
}
}
get nextLoadLevel () {
if (this.manualLevelIndex !== -1) {
return this.manualLevelIndex;
} else {
return this.hls.nextAutoLevel;
}
}
set nextLoadLevel (nextLevel) {
this.level = nextLevel;
if (this.manualLevelIndex === -1) {
this.hls.nextAutoLevel = nextLevel;
}
}
}