dashjs/src/mss/MssFragmentInfoController.js

A reference client implementation for the playback of MPEG DASH via Javascript and compliant browsers.

/**
 * The copyright in this software is being made available under the BSD License,
 * included below. 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 MssEvents from './MssEvents';
import MSSFragmentMoofProcessor from './MssFragmentMoofProcessor';
import FragmentRequest from '../streaming/vo/FragmentRequest';

function MssFragmentInfoController(config) {

    config = config || {};
    const context = this.context;

    let instance,
        logger,
        fragmentModel,
        started,
        type,
        bufferTimeout,
        startTime,
        startFragmentTime,
        index;

    const streamProcessor = config.streamProcessor;
    const eventBus = config.eventBus;
    const dashMetrics = config.dashMetrics;
    const playbackController = config.playbackController;
    const ISOBoxer = config.ISOBoxer;
    const baseURLController = config.baseURLController;
    const debug = config.debug;
    const controllerType = 'MssFragmentInfoController';

    function setup() {
        logger = debug.getLogger(instance);
    }

    function initialize() {
        started = false;

        startTime = null;
        startFragmentTime = null;

        // Register to StreamProcessor as external controller
        streamProcessor.registerExternalController(instance);
        type = streamProcessor.getType();
        fragmentModel = streamProcessor.getFragmentModel();
    }

    function doStart() {
        if (started === true) {
            return;
        }

        logger.debug('Do start');

        eventBus.on(MssEvents.FRAGMENT_INFO_LOADING_COMPLETED, onFragmentInfoLoadedCompleted, instance);

        started = true;
        startTime = new Date().getTime();
        index = 0;

        loadNextFragmentInfo();
    }

    function doStop() {
        if (!started) {
            return;
        }
        logger.debug('Do stop');

        eventBus.off(MssEvents.FRAGMENT_INFO_LOADING_COMPLETED, onFragmentInfoLoadedCompleted, instance);

        // Stop buffering process
        clearTimeout(bufferTimeout);
        started = false;

        startTime = null;
        startFragmentTime = null;
    }

    function reset() {
        doStop();
        streamProcessor.unregisterExternalController(instance);
    }

    function loadNextFragmentInfo() {
        // Check if running state
        if (!started) {
            return;
        }

        // Get last segment from SegmentTimeline
        const representation = getCurrentRepresentation();
        const manifest = representation.adaptation.period.mpd.manifest;
        const adaptation = manifest.Period_asArray[representation.adaptation.period.index].AdaptationSet_asArray[representation.adaptation.index];
        const segments = adaptation.SegmentTemplate.SegmentTimeline.S_asArray;
        const segment = segments[segments.length - 1];

        logger.debug('Last fragment time: ' + (segment.t / adaptation.SegmentTemplate.timescale));

        // Generate segment request
        const request = getRequestForSegment(adaptation, representation, segment);

        // Send segment request
        requestFragment.call(this, request);
    }

    function delayLoadNextFragmentInfo(delay) {
        clearTimeout(bufferTimeout);
        bufferTimeout = setTimeout(function () {
            bufferTimeout = null;
            loadNextFragmentInfo();
        }, delay * 1000);
    }

    function getRequestForSegment(adaptation, representation, segment) {
        let timescale = adaptation.SegmentTemplate.timescale;
        let request = new FragmentRequest();

        request.mediaType = type;
        request.type = 'FragmentInfoSegment';
        // request.range = segment.mediaRange;
        request.startTime = segment.t / timescale;
        request.duration = segment.d / timescale;
        request.timescale = timescale;
        // request.availabilityStartTime = segment.availabilityStartTime;
        // request.availabilityEndTime = segment.availabilityEndTime;
        // request.wallStartTime = segment.wallStartTime;
        request.quality = representation.index;
        request.index = index++;
        request.mediaInfo = streamProcessor.getMediaInfo();
        request.adaptationIndex = representation.adaptation.index;
        request.representationId = representation.id;
        request.url = baseURLController.resolve(representation.path).url + adaptation.SegmentTemplate.media;
        request.url = request.url.replace('$Bandwidth$', representation.bandwidth);
        request.url = request.url.replace('$Time$', segment.tManifest ? segment.tManifest : segment.t);
        request.url = request.url.replace('/Fragments(', '/FragmentInfo(');

        return request;
    }

    function getCurrentRepresentation() {
        const representationController = streamProcessor.getRepresentationController();
        const representation = representationController.getCurrentRepresentation();

        return representation;
    }

    function requestFragment(request) {

        logger.debug('Load fragment for time: ' + request.startTime);
        if (streamProcessor.getFragmentModel().isFragmentLoadedOrPending(request)) {
            // We may have reached end of timeline in case of start-over streams
            logger.debug('No more fragments');
            return;
        }

        fragmentModel.executeRequest(request);
    }

    function onFragmentInfoLoadedCompleted(e) {
        if (e.streamProcessor !== streamProcessor) {
            return;
        }

        const request = e.fragmentInfo.request;
        if (!e.fragmentInfo.response) {
            logger.error('Load error', request.url);
            return;
        }

        let deltaFragmentTime,
            deltaTime;

        logger.debug('FragmentInfo loaded: ', request.url);

        if (!startFragmentTime) {
            startFragmentTime = request.startTime;
        }

        try {
            // Process FramgentInfo in order to update segment timeline (DVR window)
            const mssFragmentMoofProcessor = MSSFragmentMoofProcessor(context).create({
                dashMetrics: dashMetrics,
                playbackController: playbackController,
                ISOBoxer: ISOBoxer,
                eventBus: eventBus,
                debug: debug
            });
            mssFragmentMoofProcessor.updateSegmentList(e.fragmentInfo, streamProcessor);

            deltaTime = (new Date().getTime() - startTime) / 1000;
            deltaFragmentTime = (request.startTime + request.duration) - startFragmentTime;
            delayLoadNextFragmentInfo(Math.max(0, (deltaFragmentTime - deltaTime)));
        } catch (e) {
            logger.fatal('Internal error while processing fragment info segment ');
        }
    }

    function getType() {
        return type;
    }

    instance = {
        initialize: initialize,
        controllerType: controllerType,
        start: doStart,
        getType: getType,
        reset: reset
    };

    setup();

    return instance;
}

MssFragmentInfoController.__dashjs_factory_name = 'MssFragmentInfoController';
export default dashjs.FactoryMaker.getClassFactory(MssFragmentInfoController); /* jshint ignore:line */