@l5i/dashjs/build/es5/src/dash/utils/SegmentsUtils.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.
 */'use strict';Object.defineProperty(exports,'__esModule',{value:true});exports.unescapeDollarsInTemplate = unescapeDollarsInTemplate;exports.replaceIDForTemplate = replaceIDForTemplate;exports.replaceTokenForTemplate = replaceTokenForTemplate;exports.getIndexBasedSegment = getIndexBasedSegment;exports.getTimeBasedSegment = getTimeBasedSegment;exports.getSegmentByIndex = getSegmentByIndex;exports.decideSegmentListRangeForTemplate = decideSegmentListRangeForTemplate;function _interopRequireDefault(obj){return obj && obj.__esModule?obj:{'default':obj};}var _voSegment=require('./../vo/Segment');var _voSegment2=_interopRequireDefault(_voSegment);function zeroPadToLength(numStr,minStrLength){while(numStr.length < minStrLength) {numStr = '0' + numStr;}return numStr;}function getNumberForSegment(segment,segmentIndex){return segment.representation.startNumber + segmentIndex;}function unescapeDollarsInTemplate(url){return url?url.split('$$').join('$'):url;}function replaceIDForTemplate(url,value){if(!value || !url || url.indexOf('$RepresentationID$') === -1){return url;}var v=value.toString();return url.split('$RepresentationID$').join(v);}function replaceTokenForTemplate(url,token,value){var formatTag='%0';var startPos=undefined,endPos=undefined,formatTagPos=undefined,specifier=undefined,width=undefined,paddedValue=undefined;var tokenLen=token.length;var formatTagLen=formatTag.length;if(!url){return url;} // keep looping round until all instances of <token> have been
// replaced. once that has happened, startPos below will be -1
// and the completed url will be returned.
while(true) { // check if there is a valid $<token>...$ identifier
// if not, return the url as is.
startPos = url.indexOf('$' + token);if(startPos < 0){return url;} // the next '$' must be the end of the identifier
// if there isn't one, return the url as is.
endPos = url.indexOf('$',startPos + tokenLen);if(endPos < 0){return url;} // now see if there is an additional format tag suffixed to
// the identifier within the enclosing '$' characters
formatTagPos = url.indexOf(formatTag,startPos + tokenLen);if(formatTagPos > startPos && formatTagPos < endPos){specifier = url.charAt(endPos - 1);width = parseInt(url.substring(formatTagPos + formatTagLen,endPos - 1),10); // support the minimum specifiers required by IEEE 1003.1
// (d, i , o, u, x, and X) for completeness
switch(specifier){ // treat all int types as uint,
// hence deliberate fallthrough
case 'd':case 'i':case 'u':paddedValue = zeroPadToLength(value.toString(),width);break;case 'x':paddedValue = zeroPadToLength(value.toString(16),width);break;case 'X':paddedValue = zeroPadToLength(value.toString(16),width).toUpperCase();break;case 'o':paddedValue = zeroPadToLength(value.toString(8),width);break;default:return url;}}else {paddedValue = value;}url = url.substring(0,startPos) + paddedValue + url.substring(endPos + 1);}}function getIndexBasedSegment(timelineConverter,isDynamic,representation,index){var seg=undefined,duration=undefined,presentationStartTime=undefined,presentationEndTime=undefined;duration = representation.segmentDuration; /*
     * From spec - If neither @duration attribute nor SegmentTimeline element is present, then the Representation
     * shall contain exactly one Media Segment. The MPD start time is 0 and the MPD duration is obtained
     * in the same way as for the last Media Segment in the Representation.
     */if(isNaN(duration)){duration = representation.adaptation.period.duration;}presentationStartTime = parseFloat((representation.adaptation.period.start + index * duration).toFixed(5));presentationEndTime = parseFloat((presentationStartTime + duration).toFixed(5));seg = new _voSegment2['default']();seg.representation = representation;seg.duration = duration;seg.presentationStartTime = presentationStartTime;seg.mediaStartTime = timelineConverter.calcMediaTimeFromPresentationTime(seg.presentationStartTime,representation);seg.availabilityStartTime = timelineConverter.calcAvailabilityStartTimeFromPresentationTime(seg.presentationStartTime,representation.adaptation.period.mpd,isDynamic);seg.availabilityEndTime = timelineConverter.calcAvailabilityEndTimeFromPresentationTime(presentationEndTime,representation.adaptation.period.mpd,isDynamic); // at this wall clock time, the video element currentTime should be seg.presentationStartTime
seg.wallStartTime = timelineConverter.calcWallTimeForSegment(seg,isDynamic);seg.replacementNumber = getNumberForSegment(seg,index);seg.availabilityIdx = index;return seg;}function getTimeBasedSegment(timelineConverter,isDynamic,representation,time,duration,fTimescale,url,range,index,tManifest){var scaledTime=time / fTimescale;var scaledDuration=Math.min(duration / fTimescale,representation.adaptation.period.mpd.maxSegmentDuration);var presentationStartTime=undefined,presentationEndTime=undefined,seg=undefined;presentationStartTime = timelineConverter.calcPresentationTimeFromMediaTime(scaledTime,representation);presentationEndTime = presentationStartTime + scaledDuration;seg = new _voSegment2['default']();seg.representation = representation;seg.duration = scaledDuration;seg.mediaStartTime = scaledTime;seg.presentationStartTime = presentationStartTime; // For SegmentTimeline every segment is available at loadedTime
seg.availabilityStartTime = representation.adaptation.period.mpd.manifest.loadedTime;seg.availabilityEndTime = timelineConverter.calcAvailabilityEndTimeFromPresentationTime(presentationEndTime,representation.adaptation.period.mpd,isDynamic); // at this wall clock time, the video element currentTime should be seg.presentationStartTime
seg.wallStartTime = timelineConverter.calcWallTimeForSegment(seg,isDynamic);seg.replacementTime = tManifest?tManifest:time;seg.replacementNumber = getNumberForSegment(seg,index);url = replaceTokenForTemplate(url,'Number',seg.replacementNumber);url = replaceTokenForTemplate(url,'Time',seg.replacementTime);seg.media = url;seg.mediaRange = range;seg.availabilityIdx = index;return seg;}function getSegmentByIndex(index,representation){if(!representation || !representation.segments)return null;var ln=representation.segments.length;var seg=undefined,i=undefined;if(index < ln){seg = representation.segments[index];if(seg && seg.availabilityIdx === index){return seg;}}for(i = 0;i < ln;i++) {seg = representation.segments[i];if(seg && seg.availabilityIdx === index){return seg;}}return null;}function decideSegmentListRangeForTemplate(timelineConverter,isDynamic,representation,requestedTime,index,givenAvailabilityUpperLimit){var duration=representation.segmentDuration;var minBufferTime=representation.adaptation.period.mpd.manifest.minBufferTime;var availabilityWindow=representation.segmentAvailabilityRange;var periodRelativeRange={start:timelineConverter.calcPeriodRelativeTimeFromMpdRelativeTime(representation,availabilityWindow?availabilityWindow.start:NaN),end:timelineConverter.calcPeriodRelativeTimeFromMpdRelativeTime(representation,availabilityWindow?availabilityWindow.end:NaN)};var currentSegmentList=representation.segments;var availabilityLowerLimit=2 * duration;var availabilityUpperLimit=givenAvailabilityUpperLimit || Math.max(2 * minBufferTime,10 * duration);var originAvailabilityTime=NaN;var originSegment=null;var start=undefined,end=undefined,range=undefined;periodRelativeRange.start = Math.max(periodRelativeRange.start,0);if(isDynamic && !timelineConverter.isTimeSyncCompleted()){start = Math.floor(periodRelativeRange.start / duration);end = Math.floor(periodRelativeRange.end / duration);range = {start:start,end:end};return range;} // if segments exist we should try to find the latest buffered time, which is the presentation time of the
// segment for the current index
if(currentSegmentList && currentSegmentList.length > 0){originSegment = getSegmentByIndex(index,representation);if(originSegment){originAvailabilityTime = timelineConverter.calcPeriodRelativeTimeFromMpdRelativeTime(representation,originSegment.presentationStartTime);}else {originAvailabilityTime = index > 0?index * duration:timelineConverter.calcPeriodRelativeTimeFromMpdRelativeTime(representation,requestedTime);}}else { // If no segments exist, but index > 0, it means that we switch to the other representation, so
// we should proceed from this time.
// Otherwise we should start from the beginning for static mpds or from the end (live edge) for dynamic mpds
originAvailabilityTime = index > 0?index * duration:isDynamic?periodRelativeRange.end:periodRelativeRange.start;} // segment list should not be out of the availability window range
start = Math.floor(Math.max(originAvailabilityTime - availabilityLowerLimit,periodRelativeRange.start) / duration);end = Math.floor(Math.min(start + availabilityUpperLimit / duration,periodRelativeRange.end / duration));range = {start:start,end:end};return range;}
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