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This software may be subject to other third party and contributor * rights, including patent rights, and no such rights are granted under this license. * * Copyright (c) 2013, Dash Industry Forum. * All rights reserved. * * Redistribution and use in source and binary forms, with or without modification, * are permitted provided that the following conditions are met: * * Redistributions of source code must retain the above copyright notice, this * list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation and/or * other materials provided with the distribution. * * Neither the name of Dash Industry Forum nor the names of its * contributors may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS AS IS AND ANY * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ import Constants from '../constants/Constants'; import MetricsConstants from '../constants/MetricsConstants'; import FragmentModel from '../models/FragmentModel'; import SourceBufferSink from '../SourceBufferSink'; import PreBufferSink from '../PreBufferSink'; import EventBus from '../../core/EventBus'; import Events from '../../core/events/Events'; import FactoryMaker from '../../core/FactoryMaker'; import Debug from '../../core/Debug'; import InitCache from '../utils/InitCache'; import DashJSError from '../vo/DashJSError'; import Errors from '../../core/errors/Errors'; import {HTTPRequest} from '../vo/metrics/HTTPRequest'; import MediaPlayerEvents from '../../streaming/MediaPlayerEvents'; const BUFFER_END_THRESHOLD = 0.5; const BUFFER_RANGE_CALCULATION_THRESHOLD = 0.01; const QUOTA_EXCEEDED_ERROR_CODE = 22; const BUFFER_CONTROLLER_TYPE = 'BufferController'; function BufferController(config) { config = config || {}; const context = this.context; const eventBus = EventBus(context).getInstance(); const errHandler = config.errHandler; const fragmentModel = config.fragmentModel; const representationController = config.representationController; const adapter = config.adapter; const textController = config.textController; const abrController = config.abrController; const playbackController = config.playbackController; const streamInfo = config.streamInfo; const type = config.type; const settings = config.settings; let instance, logger, isBufferingCompleted, bufferLevel, criticalBufferLevel, mediaSource, maxAppendedIndex, maximumIndex, sourceBufferSink, dischargeBuffer, isPrebuffering, dischargeFragments, bufferState, appendedBytesInfo, wallclockTicked, isPruningInProgress, isQuotaExceeded, initCache, pendingPruningRanges, replacingBuffer, seekTarget; function setup() { logger = Debug(context).getInstance().getLogger(instance); initCache = InitCache(context).getInstance(); resetInitialSettings(); } /** * Initialize the BufferController. Sets the media source and registers the event handlers. * @param {object} mediaSource */ function initialize(mediaSource) { setMediaSource(mediaSource); eventBus.on(Events.INIT_FRAGMENT_LOADED, _onInitFragmentLoaded, instance); eventBus.on(Events.MEDIA_FRAGMENT_LOADED, _onMediaFragmentLoaded, instance); eventBus.on(Events.WALLCLOCK_TIME_UPDATED, _onWallclockTimeUpdated, instance); eventBus.on(MediaPlayerEvents.PLAYBACK_PLAYING, _onPlaybackPlaying, instance); eventBus.on(MediaPlayerEvents.PLAYBACK_PROGRESS, _onPlaybackProgression, instance); eventBus.on(MediaPlayerEvents.PLAYBACK_TIME_UPDATED, _onPlaybackProgression, instance); eventBus.on(MediaPlayerEvents.PLAYBACK_RATE_CHANGED, _onPlaybackRateChanged, instance); eventBus.on(MediaPlayerEvents.PLAYBACK_STALLED, _onPlaybackStalled, instance); } /** * Returns the stream id * @return {string} */ function getStreamId() { return streamInfo.id; } /** * Returns the media type * @return {type} */ function getType() { return type; } /** * Returns the type of the BufferController. We distinguish between standard buffer controllers and buffer controllers related to texttracks. * @return {string} */ function getBufferControllerType() { return BUFFER_CONTROLLER_TYPE; } /** * Sets the mediasource. * @param {object} value * @param {object} mediaInfo */ function setMediaSource(value, mediaInfo = null) { return new Promise((resolve, reject) => { mediaSource = value; // if we have a prebuffer, we should prepare to discharge it, and make a new sourceBuffer ready if (sourceBufferSink && mediaInfo && typeof sourceBufferSink.discharge === 'function') { dischargeBuffer = sourceBufferSink; createBufferSink(mediaInfo) .then(() => { resolve(); }) .catch((e) => { reject(e); }) } else { resolve(); } }) } /** * Get the RepresentationInfo for a certain quality. * @param {number} quality * @return {object} * @private */ function _getRepresentationInfo(quality) { return adapter.convertRepresentationToRepresentationInfo(representationController.getRepresentationForQuality(quality)); } /** * Creates a SourceBufferSink object * @param {object} mediaInfo * @param {array} oldBufferSinks * @return {Promise<Object>} SourceBufferSink */ function createBufferSink(mediaInfo, oldBufferSinks = []) { return new Promise((resolve, reject) => { if (!initCache || !mediaInfo) { resolve(null); return; } if (mediaSource) { isPrebuffering = false; _initializeSinkForMseBuffering(mediaInfo, oldBufferSinks) .then((sink) => { resolve(sink); }) .catch((e) => { reject(e); }) } else { isPrebuffering = true; _initializeSinkForPrebuffering() .then((sink) => { resolve(sink); }) .catch((e) => { reject(e); }) } }); } function _initializeSinkForPrebuffering() { return new Promise((resolve, reject) => { const requiredQuality = abrController.getQualityFor(type, streamInfo.id); sourceBufferSink = PreBufferSink(context).create(_onAppended.bind(this)); updateBufferTimestampOffset(_getRepresentationInfo(requiredQuality)) .then(() => { resolve(sourceBufferSink); }) .catch(() => { reject(); }) }) } function _initializeSinkForMseBuffering(mediaInfo, oldBufferSinks) { return new Promise((resolve, reject) => { const requiredQuality = abrController.getQualityFor(type, streamInfo.id); sourceBufferSink = SourceBufferSink(context).create({ mediaSource, textController, eventBus }); _initializeSink(mediaInfo, oldBufferSinks, requiredQuality) .then(() => { return updateBufferTimestampOffset(_getRepresentationInfo(requiredQuality)); }) .then(() => { resolve(sourceBufferSink); }) .catch((e) => { logger.fatal('Caught error on create SourceBuffer: ' + e); errHandler.error(new DashJSError(Errors.MEDIASOURCE_TYPE_UNSUPPORTED_CODE, Errors.MEDIASOURCE_TYPE_UNSUPPORTED_MESSAGE + type)); reject(e); }); }) } function _initializeSink(mediaInfo, oldBufferSinks, requiredQuality) { const selectedRepresentation = _getRepresentationInfo(requiredQuality); if (oldBufferSinks && oldBufferSinks[type] && (type === Constants.VIDEO || type === Constants.AUDIO)) { return sourceBufferSink.initializeForStreamSwitch(mediaInfo, selectedRepresentation, oldBufferSinks[type]); } else { return sourceBufferSink.initializeForFirstUse(streamInfo, mediaInfo, selectedRepresentation); } } function dischargePreBuffer() { if (sourceBufferSink && dischargeBuffer && typeof dischargeBuffer.discharge === 'function') { const ranges = dischargeBuffer.getAllBufferRanges(); if (ranges.length > 0) { let rangeStr = 'Beginning ' + type + 'PreBuffer discharge, adding buffer for:'; for (let i = 0; i < ranges.length; i++) { rangeStr += ' start: ' + ranges.start(i) + ', end: ' + ranges.end(i) + ';'; } logger.debug(rangeStr); } else { logger.debug('PreBuffer discharge requested, but there were no media segments in the PreBuffer.'); } //A list of fragments to supress bytesAppended events for. This makes transferring from a prebuffer to a sourcebuffer silent. dischargeFragments = []; let chunks = dischargeBuffer.discharge(); let lastInit = null; for (let j = 0; j < chunks.length; j++) { const chunk = chunks[j]; if (chunk.segmentType !== HTTPRequest.INIT_SEGMENT_TYPE) { const initChunk = initCache.extract(chunk.streamId, chunk.representationId); if (initChunk) { if (lastInit !== initChunk) { dischargeFragments.push(initChunk); sourceBufferSink.append(initChunk); lastInit = initChunk; } } } dischargeFragments.push(chunk); sourceBufferSink.append(chunk); } dischargeBuffer.reset(); dischargeBuffer = null; } } /** * Callback handler when init segment has been loaded. Based on settings, the init segment is saved to the cache, and appended to the buffer. * @param {object} e * @private */ function _onInitFragmentLoaded(e) { if (settings.get().streaming.cacheInitSegments) { logger.info('Init fragment finished loading saving to', type + '\'s init cache'); initCache.save(e.chunk); } logger.debug('Append Init fragment', type, ' with representationId:', e.chunk.representationId, ' and quality:', e.chunk.quality, ', data size:', e.chunk.bytes.byteLength); _appendToBuffer(e.chunk); } /** * Append the init segment for a certain representation to the buffer. If the init segment is cached we take the one from the cache. Otherwise the function returns false and the segment has to be requested again. * @param {string} representationId * @return {boolean} */ function appendInitSegmentFromCache(representationId) { // Get init segment from cache const chunk = initCache.extract(streamInfo.id, representationId); if (!chunk) { // Init segment not in cache, shall be requested return false; } // Append init segment into buffer logger.info('Append Init fragment', type, ' with representationId:', chunk.representationId, ' and quality:', chunk.quality, ', data size:', chunk.bytes.byteLength); _appendToBuffer(chunk); return true; } /** * Calls the _appendToBuffer function to append the segment to the buffer. In case of a track switch the buffer might be cleared. * @param {object} e */ function _onMediaFragmentLoaded(e) { _appendToBuffer(e.chunk, e.request); } /** * Append data to the MSE buffer using the SourceBufferSink * @param {object} chunk * @param {object} request * @private */ function _appendToBuffer(chunk, request = null) { if (!sourceBufferSink) { return; } sourceBufferSink.append(chunk, request) .then((e) => { _onAppended(e); }) .catch((e) => { _onAppended(e); }); if (chunk.mediaInfo.type === Constants.VIDEO) { _triggerEvent(Events.VIDEO_CHUNK_RECEIVED, { chunk: chunk }); } } function _showBufferRanges(ranges) { if (ranges && ranges.length > 0) { for (let i = 0, len = ranges.length; i < len; i++) { logger.debug('Buffered range: ' + ranges.start(i) + ' - ' + ranges.end(i) + ', currentTime = ', playbackController.getTime()); } } } function _onAppended(e) { if (e.error) { // If we receive a QUOTA_EXCEEDED_ERROR_CODE we should adjust the target buffer times to avoid this error in the future. if (e.error.code === QUOTA_EXCEEDED_ERROR_CODE) { _handleQuotaExceededError(); } if (e.error.code === QUOTA_EXCEEDED_ERROR_CODE || !hasEnoughSpaceToAppend()) { logger.warn('Clearing playback buffer to overcome quota exceed situation'); // Notify ScheduleController to stop scheduling until buffer has been pruned _triggerEvent(Events.QUOTA_EXCEEDED, { criticalBufferLevel: criticalBufferLevel, quotaExceededTime: e.chunk.start }); clearBuffers(getClearRanges()); } return; } // Check if session has not been stopped in the meantime (while last segment was being appended) if (!sourceBufferSink) return; _updateBufferLevel(); isQuotaExceeded = false; appendedBytesInfo = e.chunk; if (!appendedBytesInfo || !appendedBytesInfo.endFragment) { return; } if (appendedBytesInfo && !isNaN(appendedBytesInfo.index)) { maxAppendedIndex = Math.max(appendedBytesInfo.index, maxAppendedIndex); _checkIfBufferingCompleted(); } const ranges = sourceBufferSink.getAllBufferRanges(); if (appendedBytesInfo.segmentType === HTTPRequest.MEDIA_SEGMENT_TYPE) { _showBufferRanges(ranges); _onPlaybackProgression(); _adjustSeekTarget(); } let suppressAppendedEvent = false; if (dischargeFragments) { if (dischargeFragments.indexOf(appendedBytesInfo) > 0) { suppressAppendedEvent = true; } dischargeFragments = null; } if (appendedBytesInfo && !suppressAppendedEvent) { _triggerEvent(Events.BYTES_APPENDED_END_FRAGMENT, { quality: appendedBytesInfo.quality, startTime: appendedBytesInfo.start, index: appendedBytesInfo.index, bufferedRanges: ranges, segmentType: appendedBytesInfo.segmentType, mediaType: type }); } } /** * In some cases the segment we requested might start at a different time than we initially aimed for. segments timeline/template tolerance. * We might need to do an internal seek if there is drift. * @private */ function _adjustSeekTarget() { if (isNaN(seekTarget) || isPrebuffering) return; // Check buffered data only for audio and video if (type !== Constants.AUDIO && type !== Constants.VIDEO) { seekTarget = NaN; return; } // Check if current buffered range already contains seek target (and current video element time) const currentTime = playbackController.getTime(); const rangeAtCurrenTime = getRangeAt(currentTime, 0); const rangeAtSeekTarget = getRangeAt(seekTarget, 0); if (rangeAtCurrenTime && rangeAtSeekTarget && rangeAtCurrenTime.start === rangeAtSeekTarget.start) { seekTarget = NaN; return; } // Get buffered range corresponding to the seek target const segmentDuration = representationController.getCurrentRepresentation().segmentDuration; const range = getRangeAt(seekTarget, segmentDuration); if (!range) return; if (settings.get().streaming.buffer.enableSeekDecorrelationFix && Math.abs(currentTime - seekTarget) > segmentDuration) { // If current video model time is decorrelated from seek target (and appended buffer) then seek video element // (in case of live streams on some browsers/devices for which we can't set video element time at unavalaible range) // Check if appended segment is not anterior from seek target (segments timeline/template tolerance) if (seekTarget <= range.end) { // Seek video element to seek target or range start if appended buffer starts after seek target (segments timeline/template tolerance) playbackController.seek(Math.max(seekTarget, range.start), false, true); } } else if (currentTime < range.start) { // If appended buffer starts after seek target (segments timeline/template tolerance) then seek to range start playbackController.seek(range.start, false, true); } } function _handleQuotaExceededError() { isQuotaExceeded = true; criticalBufferLevel = getTotalBufferedTime() * 0.8; logger.warn('Quota exceeded, Critical Buffer: ' + criticalBufferLevel); if (criticalBufferLevel > 0) { // recalculate buffer lengths according to criticalBufferLevel const bufferToKeep = Math.max(0.2 * criticalBufferLevel, 1); const bufferAhead = criticalBufferLevel - bufferToKeep; const bufferTimeAtTopQuality = Math.min(settings.get().streaming.buffer.bufferTimeAtTopQuality, bufferAhead * 0.9); const bufferTimeAtTopQualityLongForm = Math.min(settings.get().streaming.buffer.bufferTimeAtTopQualityLongForm, bufferAhead * 0.9); const s = { streaming: { buffer: { bufferToKeep: parseFloat(bufferToKeep.toFixed(5)), bufferTimeAtTopQuality: parseFloat(bufferTimeAtTopQuality.toFixed(5)), bufferTimeAtTopQualityLongForm: parseFloat(bufferTimeAtTopQualityLongForm.toFixed(5)) } } }; settings.update(s); } } //********************************************************************** // START Buffer Level, State & Sufficiency Handling. //********************************************************************** function prepareForPlaybackSeek() { if (isBufferingCompleted) { setIsBufferingCompleted(false); } // Abort the current request and empty all possible segments to be appended return sourceBufferSink.abort(); } function prepareForReplacementTrackSwitch(codec) { return new Promise((resolve, reject) => { sourceBufferSink.abort() .then(() => { return updateAppendWindow(); }) .then(() => { if (settings.get().streaming.buffer.useChangeTypeForTrackSwitch) { return sourceBufferSink.changeType(codec); } return Promise.resolve(); }) .then(() => { return pruneAllSafely(); }) .then(() => { setIsBufferingCompleted(false); resolve(); }) .catch((e) => { reject(e); }); }); } function prepareForForceReplacementQualitySwitch(representationInfo) { return new Promise((resolve, reject) => { sourceBufferSink.abort() .then(() => { return updateAppendWindow(); }) .then(() => { return pruneAllSafely(); }) .then(() => { // In any case we need to update the MSE.timeOffset return updateBufferTimestampOffset(representationInfo) }) .then(() => { setIsBufferingCompleted(false); resolve(); }) .catch((e) => { reject(e); }); }); } function prepareForNonReplacementTrackSwitch(codec) { return new Promise((resolve, reject) => { updateAppendWindow() .then(() => { if (settings.get().streaming.buffer.useChangeTypeForTrackSwitch) { return sourceBufferSink.changeType(codec); } return Promise.resolve(); }) .then(() => { resolve(); }) .catch((e) => { reject(e); }); }); } function pruneAllSafely() { return new Promise((resolve, reject) => { let ranges = getAllRangesWithSafetyFactor(); if (!ranges || ranges.length === 0) { _onPlaybackProgression(); resolve(); return; } clearBuffers(ranges) .then(() => { resolve(); }) .catch((e) => { reject(e); }); }); } function getAllRangesWithSafetyFactor(seekTime) { const clearRanges = []; const ranges = sourceBufferSink.getAllBufferRanges(); // no valid ranges if (!ranges || ranges.length === 0) { return clearRanges; } // if no target time is provided we clear everyhing if ((!seekTime && seekTime !== 0) || isNaN(seekTime)) { clearRanges.push({ start: ranges.start(0), end: ranges.end(ranges.length - 1) + BUFFER_END_THRESHOLD }); } // otherwise we need to calculate the correct pruning range else { const behindPruningRange = _getRangeBehindForPruning(seekTime, ranges); const aheadPruningRange = _getRangeAheadForPruning(seekTime, ranges); if (behindPruningRange) { clearRanges.push(behindPruningRange); } if (aheadPruningRange) { clearRanges.push(aheadPruningRange); } } return clearRanges; } function _getRangeBehindForPruning(targetTime, ranges) { const bufferToKeepBehind = settings.get().streaming.buffer.bufferToKeep; const startOfBuffer = ranges.start(0); // if we do a seek ahead of the current play position we do need to prune behind the new play position const behindDiff = targetTime - startOfBuffer; if (behindDiff > bufferToKeepBehind) { let rangeEnd = Math.max(0, targetTime - bufferToKeepBehind); // Ensure we keep full range of current fragment const currentTimeRequest = fragmentModel.getRequests({ state: FragmentModel.FRAGMENT_MODEL_EXECUTED, time: targetTime, threshold: BUFFER_RANGE_CALCULATION_THRESHOLD })[0]; if (currentTimeRequest) { rangeEnd = Math.min(currentTimeRequest.startTime, rangeEnd); } if (rangeEnd > 0) { return { start: startOfBuffer, end: rangeEnd }; } } return null; } function _getRangeAheadForPruning(targetTime, ranges) { // if we do a seek behind the current play position we do need to prune ahead of the new play position // we keep everything that is within bufferToKeepAhead but only if the buffer is continuous. // Otherwise we have gaps once the seek is done which might trigger an unintentional gap jump const endOfBuffer = ranges.end(ranges.length - 1) + BUFFER_END_THRESHOLD; const continuousBufferTime = getContinuousBufferTimeForTargetTime(targetTime); // This is the maximum range we keep ahead const isLongFormContent = streamInfo.manifestInfo.duration >= settings.get().streaming.buffer.longFormContentDurationThreshold; const bufferToKeepAhead = isLongFormContent ? settings.get().streaming.buffer.bufferTimeAtTopQualityLongForm : settings.get().streaming.buffer.bufferTimeAtTopQuality; // Define the start time from which we will prune. If there is no continuous range from the targettime we start immediately at the target time // Otherwise we set the start point to the end of the continuous range taking the maximum buffer to keep ahead into account let rangeStart = !isNaN(continuousBufferTime) ? Math.min(continuousBufferTime, targetTime + bufferToKeepAhead) : targetTime; // Check if we are done buffering, no need to prune then if (rangeStart >= ranges.end(ranges.length - 1)) { return null } // Ensure we keep full range of current fragment const currentTimeRequest = fragmentModel.getRequests({ state: FragmentModel.FRAGMENT_MODEL_EXECUTED, time: targetTime, threshold: BUFFER_RANGE_CALCULATION_THRESHOLD })[0]; if (currentTimeRequest) { rangeStart = Math.max(currentTimeRequest.startTime + currentTimeRequest.duration, rangeStart); } // Never remove the contiguous range of targetTime in order to avoid flushes & reenqueues when the user doesn't want it const avoidCurrentTimeRangePruning = settings.get().streaming.buffer.avoidCurrentTimeRangePruning; if (avoidCurrentTimeRangePruning) { for (let i = 0; i < ranges.length; i++) { if (ranges.start(i) <= targetTime && targetTime <= ranges.end(i) && ranges.start(i) <= rangeStart && rangeStart <= ranges.end(i)) { let oldRangeStart = rangeStart; if (i + 1 < ranges.length) { rangeStart = ranges.start(i + 1); } else { rangeStart = ranges.end(i) + 1; } logger.debug('Buffered range [' + ranges.start(i) + ', ' + ranges.end(i) + '] overlaps with targetTime ' + targetTime + ' and range to be pruned [' + oldRangeStart + ', ' + endOfBuffer + '], using [' + rangeStart + ', ' + endOfBuffer + '] instead' + ((rangeStart < endOfBuffer) ? '' : ' (no actual pruning)')); break; } } } if (rangeStart < ranges.end(ranges.length - 1)) { return { start: rangeStart, end: endOfBuffer }; } return null; } function _onPlaybackProgression() { if (!replacingBuffer || (type === Constants.TEXT && textController.isTextEnabled())) { _updateBufferLevel(); } } function _onPlaybackStalled() { checkIfSufficientBuffer(); } function _onPlaybackPlaying() { checkIfSufficientBuffer(); seekTarget = NaN; } function hasBufferAtTime(time) { try { const ranges = sourceBufferSink.getAllBufferRanges(); if (!ranges || ranges.length === 0) { return false; } let i = 0; while (i < ranges.length) { const start = ranges.start(i); const end = ranges.end(i); if (time >= start && time <= end) { return true; } i += 1;