jtBaseApp/node_modules/mpd-parser/dist/mpd-parser.es.js

/*! @name mpd-parser @version 1.1.1 @license Apache-2.0 */
import resolveUrl from '@videojs/vhs-utils/es/resolve-url';
import window from 'global/window';
import { forEachMediaGroup } from '@videojs/vhs-utils/es/media-groups';
import decodeB64ToUint8Array from '@videojs/vhs-utils/es/decode-b64-to-uint8-array';
import { DOMParser } from '@xmldom/xmldom';

var version = "1.1.1";

const isObject = obj => {
  return !!obj && typeof obj === 'object';
};

const merge = (...objects) => {
  return objects.reduce((result, source) => {
    if (typeof source !== 'object') {
      return result;
    }

    Object.keys(source).forEach(key => {
      if (Array.isArray(result[key]) && Array.isArray(source[key])) {
        result[key] = result[key].concat(source[key]);
      } else if (isObject(result[key]) && isObject(source[key])) {
        result[key] = merge(result[key], source[key]);
      } else {
        result[key] = source[key];
      }
    });
    return result;
  }, {});
};
const values = o => Object.keys(o).map(k => o[k]);

const range = (start, end) => {
  const result = [];

  for (let i = start; i < end; i++) {
    result.push(i);
  }

  return result;
};
const flatten = lists => lists.reduce((x, y) => x.concat(y), []);
const from = list => {
  if (!list.length) {
    return [];
  }

  const result = [];

  for (let i = 0; i < list.length; i++) {
    result.push(list[i]);
  }

  return result;
};
const findIndexes = (l, key) => l.reduce((a, e, i) => {
  if (e[key]) {
    a.push(i);
  }

  return a;
}, []);
/**
 * Returns a union of the included lists provided each element can be identified by a key.
 *
 * @param {Array} list - list of lists to get the union of
 * @param {Function} keyFunction - the function to use as a key for each element
 *
 * @return {Array} the union of the arrays
 */

const union = (lists, keyFunction) => {
  return values(lists.reduce((acc, list) => {
    list.forEach(el => {
      acc[keyFunction(el)] = el;
    });
    return acc;
  }, {}));
};

var errors = {
  INVALID_NUMBER_OF_PERIOD: 'INVALID_NUMBER_OF_PERIOD',
  DASH_EMPTY_MANIFEST: 'DASH_EMPTY_MANIFEST',
  DASH_INVALID_XML: 'DASH_INVALID_XML',
  NO_BASE_URL: 'NO_BASE_URL',
  MISSING_SEGMENT_INFORMATION: 'MISSING_SEGMENT_INFORMATION',
  SEGMENT_TIME_UNSPECIFIED: 'SEGMENT_TIME_UNSPECIFIED',
  UNSUPPORTED_UTC_TIMING_SCHEME: 'UNSUPPORTED_UTC_TIMING_SCHEME'
};

/**
 * @typedef {Object} SingleUri
 * @property {string} uri - relative location of segment
 * @property {string} resolvedUri - resolved location of segment
 * @property {Object} byterange - Object containing information on how to make byte range
 *   requests following byte-range-spec per RFC2616.
 * @property {String} byterange.length - length of range request
 * @property {String} byterange.offset - byte offset of range request
 *
 * @see https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.35.1
 */

/**
 * Converts a URLType node (5.3.9.2.3 Table 13) to a segment object
 * that conforms to how m3u8-parser is structured
 *
 * @see https://github.com/videojs/m3u8-parser
 *
 * @param {string} baseUrl - baseUrl provided by <BaseUrl> nodes
 * @param {string} source - source url for segment
 * @param {string} range - optional range used for range calls,
 *   follows  RFC 2616, Clause 14.35.1
 * @return {SingleUri} full segment information transformed into a format similar
 *   to m3u8-parser
 */

const urlTypeToSegment = ({
  baseUrl = '',
  source = '',
  range = '',
  indexRange = ''
}) => {
  const segment = {
    uri: source,
    resolvedUri: resolveUrl(baseUrl || '', source)
  };

  if (range || indexRange) {
    const rangeStr = range ? range : indexRange;
    const ranges = rangeStr.split('-'); // default to parsing this as a BigInt if possible

    let startRange = window.BigInt ? window.BigInt(ranges[0]) : parseInt(ranges[0], 10);
    let endRange = window.BigInt ? window.BigInt(ranges[1]) : parseInt(ranges[1], 10); // convert back to a number if less than MAX_SAFE_INTEGER

    if (startRange < Number.MAX_SAFE_INTEGER && typeof startRange === 'bigint') {
      startRange = Number(startRange);
    }

    if (endRange < Number.MAX_SAFE_INTEGER && typeof endRange === 'bigint') {
      endRange = Number(endRange);
    }

    let length;

    if (typeof endRange === 'bigint' || typeof startRange === 'bigint') {
      length = window.BigInt(endRange) - window.BigInt(startRange) + window.BigInt(1);
    } else {
      length = endRange - startRange + 1;
    }

    if (typeof length === 'bigint' && length < Number.MAX_SAFE_INTEGER) {
      length = Number(length);
    } // byterange should be inclusive according to
    // RFC 2616, Clause 14.35.1


    segment.byterange = {
      length,
      offset: startRange
    };
  }

  return segment;
};
const byteRangeToString = byterange => {
  // `endRange` is one less than `offset + length` because the HTTP range
  // header uses inclusive ranges
  let endRange;

  if (typeof byterange.offset === 'bigint' || typeof byterange.length === 'bigint') {
    endRange = window.BigInt(byterange.offset) + window.BigInt(byterange.length) - window.BigInt(1);
  } else {
    endRange = byterange.offset + byterange.length - 1;
  }

  return `${byterange.offset}-${endRange}`;
};

/**
 * parse the end number attribue that can be a string
 * number, or undefined.
 *
 * @param {string|number|undefined} endNumber
 *        The end number attribute.
 *
 * @return {number|null}
 *          The result of parsing the end number.
 */

const parseEndNumber = endNumber => {
  if (endNumber && typeof endNumber !== 'number') {
    endNumber = parseInt(endNumber, 10);
  }

  if (isNaN(endNumber)) {
    return null;
  }

  return endNumber;
};
/**
 * Functions for calculating the range of available segments in static and dynamic
 * manifests.
 */


const segmentRange = {
  /**
   * Returns the entire range of available segments for a static MPD
   *
   * @param {Object} attributes
   *        Inheritied MPD attributes
   * @return {{ start: number, end: number }}
   *         The start and end numbers for available segments
   */
  static(attributes) {
    const {
      duration,
      timescale = 1,
      sourceDuration,
      periodDuration
    } = attributes;
    const endNumber = parseEndNumber(attributes.endNumber);
    const segmentDuration = duration / timescale;

    if (typeof endNumber === 'number') {
      return {
        start: 0,
        end: endNumber
      };
    }

    if (typeof periodDuration === 'number') {
      return {
        start: 0,
        end: periodDuration / segmentDuration
      };
    }

    return {
      start: 0,
      end: sourceDuration / segmentDuration
    };
  },

  /**
   * Returns the current live window range of available segments for a dynamic MPD
   *
   * @param {Object} attributes
   *        Inheritied MPD attributes
   * @return {{ start: number, end: number }}
   *         The start and end numbers for available segments
   */
  dynamic(attributes) {
    const {
      NOW,
      clientOffset,
      availabilityStartTime,
      timescale = 1,
      duration,
      periodStart = 0,
      minimumUpdatePeriod = 0,
      timeShiftBufferDepth = Infinity
    } = attributes;
    const endNumber = parseEndNumber(attributes.endNumber); // clientOffset is passed in at the top level of mpd-parser and is an offset calculated
    // after retrieving UTC server time.

    const now = (NOW + clientOffset) / 1000; // WC stands for Wall Clock.
    // Convert the period start time to EPOCH.

    const periodStartWC = availabilityStartTime + periodStart; // Period end in EPOCH is manifest's retrieval time + time until next update.

    const periodEndWC = now + minimumUpdatePeriod;
    const periodDuration = periodEndWC - periodStartWC;
    const segmentCount = Math.ceil(periodDuration * timescale / duration);
    const availableStart = Math.floor((now - periodStartWC - timeShiftBufferDepth) * timescale / duration);
    const availableEnd = Math.floor((now - periodStartWC) * timescale / duration);
    return {
      start: Math.max(0, availableStart),
      end: typeof endNumber === 'number' ? endNumber : Math.min(segmentCount, availableEnd)
    };
  }

};
/**
 * Maps a range of numbers to objects with information needed to build the corresponding
 * segment list
 *
 * @name toSegmentsCallback
 * @function
 * @param {number} number
 *        Number of the segment
 * @param {number} index
 *        Index of the number in the range list
 * @return {{ number: Number, duration: Number, timeline: Number, time: Number }}
 *         Object with segment timing and duration info
 */

/**
 * Returns a callback for Array.prototype.map for mapping a range of numbers to
 * information needed to build the segment list.
 *
 * @param {Object} attributes
 *        Inherited MPD attributes
 * @return {toSegmentsCallback}
 *         Callback map function
 */

const toSegments = attributes => number => {
  const {
    duration,
    timescale = 1,
    periodStart,
    startNumber = 1
  } = attributes;
  return {
    number: startNumber + number,
    duration: duration / timescale,
    timeline: periodStart,
    time: number * duration
  };
};
/**
 * Returns a list of objects containing segment timing and duration info used for
 * building the list of segments. This uses the @duration attribute specified
 * in the MPD manifest to derive the range of segments.
 *
 * @param {Object} attributes
 *        Inherited MPD attributes
 * @return {{number: number, duration: number, time: number, timeline: number}[]}
 *         List of Objects with segment timing and duration info
 */

const parseByDuration = attributes => {
  const {
    type,
    duration,
    timescale = 1,
    periodDuration,
    sourceDuration
  } = attributes;
  const {
    start,
    end
  } = segmentRange[type](attributes);
  const segments = range(start, end).map(toSegments(attributes));

  if (type === 'static') {
    const index = segments.length - 1; // section is either a period or the full source

    const sectionDuration = typeof periodDuration === 'number' ? periodDuration : sourceDuration; // final segment may be less than full segment duration

    segments[index].duration = sectionDuration - duration / timescale * index;
  }

  return segments;
};

/**
 * Translates SegmentBase into a set of segments.
 * (DASH SPEC Section 5.3.9.3.2) contains a set of <SegmentURL> nodes.  Each
 * node should be translated into segment.
 *
 * @param {Object} attributes
 *   Object containing all inherited attributes from parent elements with attribute
 *   names as keys
 * @return {Object.<Array>} list of segments
 */

const segmentsFromBase = attributes => {
  const {
    baseUrl,
    initialization = {},
    sourceDuration,
    indexRange = '',
    periodStart,
    presentationTime,
    number = 0,
    duration
  } = attributes; // base url is required for SegmentBase to work, per spec (Section 5.3.9.2.1)

  if (!baseUrl) {
    throw new Error(errors.NO_BASE_URL);
  }

  const initSegment = urlTypeToSegment({
    baseUrl,
    source: initialization.sourceURL,
    range: initialization.range
  });
  const segment = urlTypeToSegment({
    baseUrl,
    source: baseUrl,
    indexRange
  });
  segment.map = initSegment; // If there is a duration, use it, otherwise use the given duration of the source
  // (since SegmentBase is only for one total segment)

  if (duration) {
    const segmentTimeInfo = parseByDuration(attributes);

    if (segmentTimeInfo.length) {
      segment.duration = segmentTimeInfo[0].duration;
      segment.timeline = segmentTimeInfo[0].timeline;
    }
  } else if (sourceDuration) {
    segment.duration = sourceDuration;
    segment.timeline = periodStart;
  } // If presentation time is provided, these segments are being generated by SIDX
  // references, and should use the time provided. For the general case of SegmentBase,
  // there should only be one segment in the period, so its presentation time is the same
  // as its period start.


  segment.presentationTime = presentationTime || periodStart;
  segment.number = number;
  return [segment];
};
/**
 * Given a playlist, a sidx box, and a baseUrl, update the segment list of the playlist
 * according to the sidx information given.
 *
 * playlist.sidx has metadadata about the sidx where-as the sidx param
 * is the parsed sidx box itself.
 *
 * @param {Object} playlist the playlist to update the sidx information for
 * @param {Object} sidx the parsed sidx box
 * @return {Object} the playlist object with the updated sidx information
 */

const addSidxSegmentsToPlaylist$1 = (playlist, sidx, baseUrl) => {
  // Retain init segment information
  const initSegment = playlist.sidx.map ? playlist.sidx.map : null; // Retain source duration from initial main manifest parsing

  const sourceDuration = playlist.sidx.duration; // Retain source timeline

  const timeline = playlist.timeline || 0;
  const sidxByteRange = playlist.sidx.byterange;
  const sidxEnd = sidxByteRange.offset + sidxByteRange.length; // Retain timescale of the parsed sidx

  const timescale = sidx.timescale; // referenceType 1 refers to other sidx boxes

  const mediaReferences = sidx.references.filter(r => r.referenceType !== 1);
  const segments = [];
  const type = playlist.endList ? 'static' : 'dynamic';
  const periodStart = playlist.sidx.timeline;
  let presentationTime = periodStart;
  let number = playlist.mediaSequence || 0; // firstOffset is the offset from the end of the sidx box

  let startIndex; // eslint-disable-next-line

  if (typeof sidx.firstOffset === 'bigint') {
    startIndex = window.BigInt(sidxEnd) + sidx.firstOffset;
  } else {
    startIndex = sidxEnd + sidx.firstOffset;
  }

  for (let i = 0; i < mediaReferences.length; i++) {
    const reference = sidx.references[i]; // size of the referenced (sub)segment

    const size = reference.referencedSize; // duration of the referenced (sub)segment, in  the  timescale
    // this will be converted to seconds when generating segments

    const duration = reference.subsegmentDuration; // should be an inclusive range

    let endIndex; // eslint-disable-next-line

    if (typeof startIndex === 'bigint') {
      endIndex = startIndex + window.BigInt(size) - window.BigInt(1);
    } else {
      endIndex = startIndex + size - 1;
    }

    const indexRange = `${startIndex}-${endIndex}`;
    const attributes = {
      baseUrl,
      timescale,
      timeline,
      periodStart,
      presentationTime,
      number,
      duration,
      sourceDuration,
      indexRange,
      type
    };
    const segment = segmentsFromBase(attributes)[0];

    if (initSegment) {
      segment.map = initSegment;
    }

    segments.push(segment);

    if (typeof startIndex === 'bigint') {
      startIndex += window.BigInt(size);
    } else {
      startIndex += size;
    }

    presentationTime += duration / timescale;
    number++;
  }

  playlist.segments = segments;
  return playlist;
};

const SUPPORTED_MEDIA_TYPES = ['AUDIO', 'SUBTITLES']; // allow one 60fps frame as leniency (arbitrarily chosen)

const TIME_FUDGE = 1 / 60;
/**
 * Given a list of timelineStarts, combines, dedupes, and sorts them.
 *
 * @param {TimelineStart[]} timelineStarts - list of timeline starts
 *
 * @return {TimelineStart[]} the combined and deduped timeline starts
 */

const getUniqueTimelineStarts = timelineStarts => {
  return union(timelineStarts, ({
    timeline
  }) => timeline).sort((a, b) => a.timeline > b.timeline ? 1 : -1);
};
/**
 * Finds the playlist with the matching NAME attribute.
 *
 * @param {Array} playlists - playlists to search through
 * @param {string} name - the NAME attribute to search for
 *
 * @return {Object|null} the matching playlist object, or null
 */

const findPlaylistWithName = (playlists, name) => {
  for (let i = 0; i < playlists.length; i++) {
    if (playlists[i].attributes.NAME === name) {
      return playlists[i];
    }
  }

  return null;
};
/**
 * Gets a flattened array of media group playlists.
 *
 * @param {Object} manifest - the main manifest object
 *
 * @return {Array} the media group playlists
 */

const getMediaGroupPlaylists = manifest => {
  let mediaGroupPlaylists = [];
  forEachMediaGroup(manifest, SUPPORTED_MEDIA_TYPES, (properties, type, group, label) => {
    mediaGroupPlaylists = mediaGroupPlaylists.concat(properties.playlists || []);
  });
  return mediaGroupPlaylists;
};
/**
 * Updates the playlist's media sequence numbers.
 *
 * @param {Object} config - options object
 * @param {Object} config.playlist - the playlist to update
 * @param {number} config.mediaSequence - the mediaSequence number to start with
 */

const updateMediaSequenceForPlaylist = ({
  playlist,
  mediaSequence
}) => {
  playlist.mediaSequence = mediaSequence;
  playlist.segments.forEach((segment, index) => {
    segment.number = playlist.mediaSequence + index;
  });
};
/**
 * Updates the media and discontinuity sequence numbers of newPlaylists given oldPlaylists
 * and a complete list of timeline starts.
 *
 * If no matching playlist is found, only the discontinuity sequence number of the playlist
 * will be updated.
 *
 * Since early available timelines are not supported, at least one segment must be present.
 *
 * @param {Object} config - options object
 * @param {Object[]} oldPlaylists - the old playlists to use as a reference
 * @param {Object[]} newPlaylists - the new playlists to update
 * @param {Object} timelineStarts - all timelineStarts seen in the stream to this point
 */

const updateSequenceNumbers = ({
  oldPlaylists,
  newPlaylists,
  timelineStarts
}) => {
  newPlaylists.forEach(playlist => {
    playlist.discontinuitySequence = timelineStarts.findIndex(function ({
      timeline
    }) {
      return timeline === playlist.timeline;
    }); // Playlists NAMEs come from DASH Representation IDs, which are mandatory
    // (see ISO_23009-1-2012 5.3.5.2).
    //
    // If the same Representation existed in a prior Period, it will retain the same NAME.

    const oldPlaylist = findPlaylistWithName(oldPlaylists, playlist.attributes.NAME);

    if (!oldPlaylist) {
      // Since this is a new playlist, the media sequence values can start from 0 without
      // consequence.
      return;
    } // TODO better support for live SIDX
    //
    // As of this writing, mpd-parser does not support multiperiod SIDX (in live or VOD).
    // This is evident by a playlist only having a single SIDX reference. In a multiperiod
    // playlist there would need to be multiple SIDX references. In addition, live SIDX is
    // not supported when the SIDX properties change on refreshes.
    //
    // In the future, if support needs to be added, the merging logic here can be called
    // after SIDX references are resolved. For now, exit early to prevent exceptions being
    // thrown due to undefined references.


    if (playlist.sidx) {
      return;
    } // Since we don't yet support early available timelines, we don't need to support
    // playlists with no segments.


    const firstNewSegment = playlist.segments[0];
    const oldMatchingSegmentIndex = oldPlaylist.segments.findIndex(function (oldSegment) {
      return Math.abs(oldSegment.presentationTime - firstNewSegment.presentationTime) < TIME_FUDGE;
    }); // No matching segment from the old playlist means the entire playlist was refreshed.
    // In this case the media sequence should account for this update, and the new segments
    // should be marked as discontinuous from the prior content, since the last prior
    // timeline was removed.

    if (oldMatchingSegmentIndex === -1) {
      updateMediaSequenceForPlaylist({
        playlist,
        mediaSequence: oldPlaylist.mediaSequence + oldPlaylist.segments.length
      });
      playlist.segments[0].discontinuity = true;
      playlist.discontinuityStarts.unshift(0); // No matching segment does not necessarily mean there's missing content.
      //
      // If the new playlist's timeline is the same as the last seen segment's timeline,
      // then a discontinuity can be added to identify that there's potentially missing
      // content. If there's no missing content, the discontinuity should still be rather
      // harmless. It's possible that if segment durations are accurate enough, that the
      // existence of a gap can be determined using the presentation times and durations,
      // but if the segment timing info is off, it may introduce more problems than simply
      // adding the discontinuity.
      //
      // If the new playlist's timeline is different from the last seen segment's timeline,
      // then a discontinuity can be added to identify that this is the first seen segment
      // of a new timeline. However, the logic at the start of this function that
      // determined the disconinuity sequence by timeline index is now off by one (the
      // discontinuity of the newest timeline hasn't yet fallen off the manifest...since
      // we added it), so the disconinuity sequence must be decremented.
      //
      // A period may also have a duration of zero, so the case of no segments is handled
      // here even though we don't yet support early available periods.

      if (!oldPlaylist.segments.length && playlist.timeline > oldPlaylist.timeline || oldPlaylist.segments.length && playlist.timeline > oldPlaylist.segments[oldPlaylist.segments.length - 1].timeline) {
        playlist.discontinuitySequence--;
      }

      return;
    } // If the first segment matched with a prior segment on a discontinuity (it's matching
    // on the first segment of a period), then the discontinuitySequence shouldn't be the
    // timeline's matching one, but instead should be the one prior, and the first segment
    // of the new manifest should be marked with a discontinuity.
    //
    // The reason for this special case is that discontinuity sequence shows how many
    // discontinuities have fallen off of the playlist, and discontinuities are marked on
    // the first segment of a new "timeline." Because of this, while DASH will retain that
    // Period while the "timeline" exists, HLS keeps track of it via the discontinuity
    // sequence, and that first segment is an indicator, but can be removed before that
    // timeline is gone.


    const oldMatchingSegment = oldPlaylist.segments[oldMatchingSegmentIndex];

    if (oldMatchingSegment.discontinuity && !firstNewSegment.discontinuity) {
      firstNewSegment.discontinuity = true;
      playlist.discontinuityStarts.unshift(0);
      playlist.discontinuitySequence--;
    }

    updateMediaSequenceForPlaylist({
      playlist,
      mediaSequence: oldPlaylist.segments[oldMatchingSegmentIndex].number
    });
  });
};
/**
 * Given an old parsed manifest object and a new parsed manifest object, updates the
 * sequence and timing values within the new manifest to ensure that it lines up with the
 * old.
 *
 * @param {Array} oldManifest - the old main manifest object
 * @param {Array} newManifest - the new main manifest object
 *
 * @return {Object} the updated new manifest object
 */

const positionManifestOnTimeline = ({
  oldManifest,
  newManifest
}) => {
  // Starting from v4.1.2 of the IOP, section 4.4.3.3 states:
  //
  // "MPD@availabilityStartTime and Period@start shall not be changed over MPD updates."
  //
  // This was added from https://github.com/Dash-Industry-Forum/DASH-IF-IOP/issues/160
  //
  // Because of this change, and the difficulty of supporting periods with changing start
  // times, periods with changing start times are not supported. This makes the logic much
  // simpler, since periods with the same start time can be considerred the same period
  // across refreshes.
  //
  // To give an example as to the difficulty of handling periods where the start time may
  // change, if a single period manifest is refreshed with another manifest with a single
  // period, and both the start and end times are increased, then the only way to determine
  // if it's a new period or an old one that has changed is to look through the segments of
  // each playlist and determine the presentation time bounds to find a match. In addition,
  // if the period start changed to exceed the old period end, then there would be no
  // match, and it would not be possible to determine whether the refreshed period is a new
  // one or the old one.
  const oldPlaylists = oldManifest.playlists.concat(getMediaGroupPlaylists(oldManifest));
  const newPlaylists = newManifest.playlists.concat(getMediaGroupPlaylists(newManifest)); // Save all seen timelineStarts to the new manifest. Although this potentially means that
  // there's a "memory leak" in that it will never stop growing, in reality, only a couple
  // of properties are saved for each seen Period. Even long running live streams won't
  // generate too many Periods, unless the stream is watched for decades. In the future,
  // this can be optimized by mapping to discontinuity sequence numbers for each timeline,
  // but it may not become an issue, and the additional info can be useful for debugging.

  newManifest.timelineStarts = getUniqueTimelineStarts([oldManifest.timelineStarts, newManifest.timelineStarts]);
  updateSequenceNumbers({
    oldPlaylists,
    newPlaylists,
    timelineStarts: newManifest.timelineStarts
  });
  return newManifest;
};

const generateSidxKey = sidx => sidx && sidx.uri + '-' + byteRangeToString(sidx.byterange);

const mergeDiscontiguousPlaylists = playlists => {
  const mergedPlaylists = values(playlists.reduce((acc, playlist) => {
    // assuming playlist IDs are the same across periods
    // TODO: handle multiperiod where representation sets are not the same
    // across periods
    const name = playlist.attributes.id + (playlist.attributes.lang || '');

    if (!acc[name]) {
      // First Period
      acc[name] = playlist;
      acc[name].attributes.timelineStarts = [];
    } else {
      // Subsequent Periods
      if (playlist.segments) {
        // first segment of subsequent periods signal a discontinuity
        if (playlist.segments[0]) {
          playlist.segments[0].discontinuity = true;
        }

        acc[name].segments.push(...playlist.segments);
      } // bubble up contentProtection, this assumes all DRM content
      // has the same contentProtection


      if (playlist.attributes.contentProtection) {
        acc[name].attributes.contentProtection = playlist.attributes.contentProtection;
      }
    }

    acc[name].attributes.timelineStarts.push({
      // Although they represent the same number, it's important to have both to make it
      // compatible with HLS potentially having a similar attribute.
      start: playlist.attributes.periodStart,
      timeline: playlist.attributes.periodStart
    });
    return acc;
  }, {}));
  return mergedPlaylists.map(playlist => {
    playlist.discontinuityStarts = findIndexes(playlist.segments || [], 'discontinuity');
    return playlist;
  });
};

const addSidxSegmentsToPlaylist = (playlist, sidxMapping) => {
  const sidxKey = generateSidxKey(playlist.sidx);
  const sidxMatch = sidxKey && sidxMapping[sidxKey] && sidxMapping[sidxKey].sidx;

  if (sidxMatch) {
    addSidxSegmentsToPlaylist$1(playlist, sidxMatch, playlist.sidx.resolvedUri);
  }

  return playlist;
};
const addSidxSegmentsToPlaylists = (playlists, sidxMapping = {}) => {
  if (!Object.keys(sidxMapping).length) {
    return playlists;
  }

  for (const i in playlists) {
    playlists[i] = addSidxSegmentsToPlaylist(playlists[i], sidxMapping);
  }

  return playlists;
};
const formatAudioPlaylist = ({
  attributes,
  segments,
  sidx,
  mediaSequence,
  discontinuitySequence,
  discontinuityStarts
}, isAudioOnly) => {
  const playlist = {
    attributes: {
      NAME: attributes.id,
      BANDWIDTH: attributes.bandwidth,
      CODECS: attributes.codecs,
      ['PROGRAM-ID']: 1
    },
    uri: '',
    endList: attributes.type === 'static',
    timeline: attributes.periodStart,
    resolvedUri: '',
    targetDuration: attributes.duration,
    discontinuitySequence,
    discontinuityStarts,
    timelineStarts: attributes.timelineStarts,
    mediaSequence,
    segments
  };

  if (attributes.contentProtection) {
    playlist.contentProtection = attributes.contentProtection;
  }

  if (sidx) {
    playlist.sidx = sidx;
  }

  if (isAudioOnly) {
    playlist.attributes.AUDIO = 'audio';
    playlist.attributes.SUBTITLES = 'subs';
  }

  return playlist;
};
const formatVttPlaylist = ({
  attributes,
  segments,
  mediaSequence,
  discontinuityStarts,
  discontinuitySequence
}) => {
  if (typeof segments === 'undefined') {
    // vtt tracks may use single file in BaseURL
    segments = [{
      uri: attributes.baseUrl,
      timeline: attributes.periodStart,
      resolvedUri: attributes.baseUrl || '',
      duration: attributes.sourceDuration,
      number: 0
    }]; // targetDuration should be the same duration as the only segment

    attributes.duration = attributes.sourceDuration;
  }

  const m3u8Attributes = {
    NAME: attributes.id,
    BANDWIDTH: attributes.bandwidth,
    ['PROGRAM-ID']: 1
  };

  if (attributes.codecs) {
    m3u8Attributes.CODECS = attributes.codecs;
  }

  return {
    attributes: m3u8Attributes,
    uri: '',
    endList: attributes.type === 'static',
    timeline: attributes.periodStart,
    resolvedUri: attributes.baseUrl || '',
    targetDuration: attributes.duration,
    timelineStarts: attributes.timelineStarts,
    discontinuityStarts,
    discontinuitySequence,
    mediaSequence,
    segments
  };
};
const organizeAudioPlaylists = (playlists, sidxMapping = {}, isAudioOnly = false) => {
  let mainPlaylist;
  const formattedPlaylists = playlists.reduce((a, playlist) => {
    const role = playlist.attributes.role && playlist.attributes.role.value || '';
    const language = playlist.attributes.lang || '';
    let label = playlist.attributes.label || 'main';

    if (language && !playlist.attributes.label) {
      const roleLabel = role ? ` (${role})` : '';
      label = `${playlist.attributes.lang}${roleLabel}`;
    }

    if (!a[label]) {
      a[label] = {
        language,
        autoselect: true,
        default: role === 'main',
        playlists: [],
        uri: ''
      };
    }

    const formatted = addSidxSegmentsToPlaylist(formatAudioPlaylist(playlist, isAudioOnly), sidxMapping);
    a[label].playlists.push(formatted);

    if (typeof mainPlaylist === 'undefined' && role === 'main') {
      mainPlaylist = playlist;
      mainPlaylist.default = true;
    }

    return a;
  }, {}); // if no playlists have role "main", mark the first as main

  if (!mainPlaylist) {
    const firstLabel = Object.keys(formattedPlaylists)[0];
    formattedPlaylists[firstLabel].default = true;
  }

  return formattedPlaylists;
};
const organizeVttPlaylists = (playlists, sidxMapping = {}) => {
  return playlists.reduce((a, playlist) => {
    const label = playlist.attributes.label || playlist.attributes.lang || 'text';

    if (!a[label]) {
      a[label] = {
        language: label,
        default: false,
        autoselect: false,
        playlists: [],
        uri: ''
      };
    }

    a[label].playlists.push(addSidxSegmentsToPlaylist(formatVttPlaylist(playlist), sidxMapping));
    return a;
  }, {});
};

const organizeCaptionServices = captionServices => captionServices.reduce((svcObj, svc) => {
  if (!svc) {
    return svcObj;
  }

  svc.forEach(service => {
    const {
      channel,
      language
    } = service;
    svcObj[language] = {
      autoselect: false,
      default: false,
      instreamId: channel,
      language
    };

    if (service.hasOwnProperty('aspectRatio')) {
      svcObj[language].aspectRatio = service.aspectRatio;
    }

    if (service.hasOwnProperty('easyReader')) {
      svcObj[language].easyReader = service.easyReader;
    }

    if (service.hasOwnProperty('3D')) {
      svcObj[language]['3D'] = service['3D'];
    }
  });
  return svcObj;
}, {});

const formatVideoPlaylist = ({
  attributes,
  segments,
  sidx,
  discontinuityStarts
}) => {
  const playlist = {
    attributes: {
      NAME: attributes.id,
      AUDIO: 'audio',
      SUBTITLES: 'subs',
      RESOLUTION: {
        width: attributes.width,
        height: attributes.height
      },
      CODECS: attributes.codecs,
      BANDWIDTH: attributes.bandwidth,
      ['PROGRAM-ID']: 1
    },
    uri: '',
    endList: attributes.type === 'static',
    timeline: attributes.periodStart,
    resolvedUri: '',
    targetDuration: attributes.duration,
    discontinuityStarts,
    timelineStarts: attributes.timelineStarts,
    segments
  };

  if (attributes.frameRate) {
    playlist.attributes['FRAME-RATE'] = attributes.frameRate;
  }

  if (attributes.contentProtection) {
    playlist.contentProtection = attributes.contentProtection;
  }

  if (sidx) {
    playlist.sidx = sidx;
  }

  return playlist;
};

const videoOnly = ({
  attributes
}) => attributes.mimeType === 'video/mp4' || attributes.mimeType === 'video/webm' || attributes.contentType === 'video';

const audioOnly = ({
  attributes
}) => attributes.mimeType === 'audio/mp4' || attributes.mimeType === 'audio/webm' || attributes.contentType === 'audio';

const vttOnly = ({
  attributes
}) => attributes.mimeType === 'text/vtt' || attributes.contentType === 'text';
/**
 * Contains start and timeline properties denoting a timeline start. For DASH, these will
 * be the same number.
 *
 * @typedef {Object} TimelineStart
 * @property {number} start - the start time of the timeline
 * @property {number} timeline - the timeline number
 */

/**
 * Adds appropriate media and discontinuity sequence values to the segments and playlists.
 *
 * Throughout mpd-parser, the `number` attribute is used in relation to `startNumber`, a
 * DASH specific attribute used in constructing segment URI's from templates. However, from
 * an HLS perspective, the `number` attribute on a segment would be its `mediaSequence`
 * value, which should start at the original media sequence value (or 0) and increment by 1
 * for each segment thereafter. Since DASH's `startNumber` values are independent per
 * period, it doesn't make sense to use it for `number`. Instead, assume everything starts
 * from a 0 mediaSequence value and increment from there.
 *
 * Note that VHS currently doesn't use the `number` property, but it can be helpful for
 * debugging and making sense of the manifest.
 *
 * For live playlists, to account for values increasing in manifests when periods are
 * removed on refreshes, merging logic should be used to update the numbers to their
 * appropriate values (to ensure they're sequential and increasing).
 *
 * @param {Object[]} playlists - the playlists to update
 * @param {TimelineStart[]} timelineStarts - the timeline starts for the manifest
 */


const addMediaSequenceValues = (playlists, timelineStarts) => {
  // increment all segments sequentially
  playlists.forEach(playlist => {
    playlist.mediaSequence = 0;
    playlist.discontinuitySequence = timelineStarts.findIndex(function ({
      timeline
    }) {
      return timeline === playlist.timeline;
    });

    if (!playlist.segments) {
      return;
    }

    playlist.segments.forEach((segment, index) => {
      segment.number = index;
    });
  });
};
/**
 * Given a media group object, flattens all playlists within the media group into a single
 * array.
 *
 * @param {Object} mediaGroupObject - the media group object
 *
 * @return {Object[]}
 *         The media group playlists
 */

const flattenMediaGroupPlaylists = mediaGroupObject => {
  if (!mediaGroupObject) {
    return [];
  }

  return Object.keys(mediaGroupObject).reduce((acc, label) => {
    const labelContents = mediaGroupObject[label];
    return acc.concat(labelContents.playlists);
  }, []);
};
const toM3u8 = ({
  dashPlaylists,
  locations,
  sidxMapping = {},
  previousManifest,
  eventStream
}) => {
  if (!dashPlaylists.length) {
    return {};
  } // grab all main manifest attributes


  const {
    sourceDuration: duration,
    type,
    suggestedPresentationDelay,
    minimumUpdatePeriod
  } = dashPlaylists[0].attributes;
  const videoPlaylists = mergeDiscontiguousPlaylists(dashPlaylists.filter(videoOnly)).map(formatVideoPlaylist);
  const audioPlaylists = mergeDiscontiguousPlaylists(dashPlaylists.filter(audioOnly));
  const vttPlaylists = mergeDiscontiguousPlaylists(dashPlaylists.filter(vttOnly));
  const captions = dashPlaylists.map(playlist => playlist.attributes.captionServices).filter(Boolean);
  const manifest = {
    allowCache: true,
    discontinuityStarts: [],
    segments: [],
    endList: true,
    mediaGroups: {
      AUDIO: {},
      VIDEO: {},
      ['CLOSED-CAPTIONS']: {},
      SUBTITLES: {}
    },
    uri: '',
    duration,
    playlists: addSidxSegmentsToPlaylists(videoPlaylists, sidxMapping)
  };

  if (minimumUpdatePeriod >= 0) {
    manifest.minimumUpdatePeriod = minimumUpdatePeriod * 1000;
  }

  if (locations) {
    manifest.locations = locations;
  }

  if (type === 'dynamic') {
    manifest.suggestedPresentationDelay = suggestedPresentationDelay;
  }

  if (eventStream && eventStream.length > 0) {
    manifest.eventStream = eventStream;
  }

  const isAudioOnly = manifest.playlists.length === 0;
  const organizedAudioGroup = audioPlaylists.length ? organizeAudioPlaylists(audioPlaylists, sidxMapping, isAudioOnly) : null;
  const organizedVttGroup = vttPlaylists.length ? organizeVttPlaylists(vttPlaylists, sidxMapping) : null;
  const formattedPlaylists = videoPlaylists.concat(flattenMediaGroupPlaylists(organizedAudioGroup), flattenMediaGroupPlaylists(organizedVttGroup));
  const playlistTimelineStarts = formattedPlaylists.map(({
    timelineStarts
  }) => timelineStarts);
  manifest.timelineStarts = getUniqueTimelineStarts(playlistTimelineStarts);
  addMediaSequenceValues(formattedPlaylists, manifest.timelineStarts);

  if (organizedAudioGroup) {
    manifest.mediaGroups.AUDIO.audio = organizedAudioGroup;
  }

  if (organizedVttGroup) {
    manifest.mediaGroups.SUBTITLES.subs = organizedVttGroup;
  }

  if (captions.length) {
    manifest.mediaGroups['CLOSED-CAPTIONS'].cc = organizeCaptionServices(captions);
  }

  if (previousManifest) {
    return positionManifestOnTimeline({
      oldManifest: previousManifest,
      newManifest: manifest
    });
  }

  return manifest;
};

/**
 * Calculates the R (repetition) value for a live stream (for the final segment
 * in a manifest where the r value is negative 1)
 *
 * @param {Object} attributes
 *        Object containing all inherited attributes from parent elements with attribute
 *        names as keys
 * @param {number} time
 *        current time (typically the total time up until the final segment)
 * @param {number} duration
 *        duration property for the given <S />
 *
 * @return {number}
 *        R value to reach the end of the given period
 */
const getLiveRValue = (attributes, time, duration) => {
  const {
    NOW,
    clientOffset,
    availabilityStartTime,
    timescale = 1,
    periodStart = 0,
    minimumUpdatePeriod = 0
  } = attributes;
  const now = (NOW + clientOffset) / 1000;
  const periodStartWC = availabilityStartTime + periodStart;
  const periodEndWC = now + minimumUpdatePeriod;
  const periodDuration = periodEndWC - periodStartWC;
  return Math.ceil((periodDuration * timescale - time) / duration);
};
/**
 * Uses information provided by SegmentTemplate.SegmentTimeline to determine segment
 * timing and duration
 *
 * @param {Object} attributes
 *        Object containing all inherited attributes from parent elements with attribute
 *        names as keys
 * @param {Object[]} segmentTimeline
 *        List of objects representing the attributes of each S element contained within
 *
 * @return {{number: number, duration: number, time: number, timeline: number}[]}
 *         List of Objects with segment timing and duration info
 */


const parseByTimeline = (attributes, segmentTimeline) => {
  const {
    type,
    minimumUpdatePeriod = 0,
    media = '',
    sourceDuration,
    timescale = 1,
    startNumber = 1,
    periodStart: timeline
  } = attributes;
  const segments = [];
  let time = -1;

  for (let sIndex = 0; sIndex < segmentTimeline.length; sIndex++) {
    const S = segmentTimeline[sIndex];
    const duration = S.d;
    const repeat = S.r || 0;
    const segmentTime = S.t || 0;

    if (time < 0) {
      // first segment
      time = segmentTime;
    }

    if (segmentTime && segmentTime > time) {
      // discontinuity
      // TODO: How to handle this type of discontinuity
      // timeline++ here would treat it like HLS discontuity and content would
      // get appended without gap
      // E.G.
      //  <S t="0" d="1" />
      //  <S d="1" />
      //  <S d="1" />
      //  <S t="5" d="1" />
      // would have $Time$ values of [0, 1, 2, 5]
      // should this be appened at time positions [0, 1, 2, 3],(#EXT-X-DISCONTINUITY)
      // or [0, 1, 2, gap, gap, 5]? (#EXT-X-GAP)
      // does the value of sourceDuration consider this when calculating arbitrary
      // negative @r repeat value?
      // E.G. Same elements as above with this added at the end
      //  <S d="1" r="-1" />
      //  with a sourceDuration of 10
      // Would the 2 gaps be included in the time duration calculations resulting in
      // 8 segments with $Time$ values of [0, 1, 2, 5, 6, 7, 8, 9] or 10 segments
      // with $Time$ values of [0, 1, 2, 5, 6, 7, 8, 9, 10, 11] ?
      time = segmentTime;
    }

    let count;

    if (repeat < 0) {
      const nextS = sIndex + 1;

      if (nextS === segmentTimeline.length) {
        // last segment
        if (type === 'dynamic' && minimumUpdatePeriod > 0 && media.indexOf('$Number$') > 0) {
          count = getLiveRValue(attributes, time, duration);
        } else {
          // TODO: This may be incorrect depending on conclusion of TODO above
          count = (sourceDuration * timescale - time) / duration;
        }
      } else {
        count = (segmentTimeline[nextS].t - time) / duration;
      }
    } else {
      count = repeat + 1;
    }

    const end = startNumber + segments.length + count;
    let number = startNumber + segments.length;

    while (number < end) {
      segments.push({
        number,
        duration: duration / timescale,
        time,
        timeline
      });
      time += duration;
      number++;
    }
  }

  return segments;
};

const identifierPattern = /\$([A-z]*)(?:(%0)([0-9]+)d)?\$/g;
/**
 * Replaces template identifiers with corresponding values. To be used as the callback
 * for String.prototype.replace
 *
 * @name replaceCallback
 * @function
 * @param {string} match
 *        Entire match of identifier
 * @param {string} identifier
 *        Name of matched identifier
 * @param {string} format
 *        Format tag string. Its presence indicates that padding is expected
 * @param {string} width
 *        Desired length of the replaced value. Values less than this width shall be left
 *        zero padded
 * @return {string}
 *         Replacement for the matched identifier
 */

/**
 * Returns a function to be used as a callback for String.prototype.replace to replace
 * template identifiers
 *
 * @param {Obect} values
 *        Object containing values that shall be used to replace known identifiers
 * @param {number} values.RepresentationID
 *        Value of the Representation@id attribute
 * @param {number} values.Number
 *        Number of the corresponding segment
 * @param {number} values.Bandwidth
 *        Value of the Representation@bandwidth attribute.
 * @param {number} values.Time
 *        Timestamp value of the corresponding segment
 * @return {replaceCallback}
 *         Callback to be used with String.prototype.replace to replace identifiers
 */

const identifierReplacement = values => (match, identifier, format, width) => {
  if (match === '$$') {
    // escape sequence
    return '$';
  }

  if (typeof values[identifier] === 'undefined') {
    return match;
  }

  const value = '' + values[identifier];

  if (identifier === 'RepresentationID') {
    // Format tag shall not be present with RepresentationID
    return value;
  }

  if (!format) {
    width = 1;
  } else {
    width = parseInt(width, 10);
  }

  if (value.length >= width) {
    return value;
  }

  return `${new Array(width - value.length + 1).join('0')}${value}`;
};
/**
 * Constructs a segment url from a template string
 *
 * @param {string} url
 *        Template string to construct url from
 * @param {Obect} values
 *        Object containing values that shall be used to replace known identifiers
 * @param {number} values.RepresentationID
 *        Value of the Representation@id attribute
 * @param {number} values.Number
 *        Number of the corresponding segment
 * @param {number} values.Bandwidth
 *        Value of the Representation@bandwidth attribute.
 * @param {number} values.Time
 *        Timestamp value of the corresponding segment
 * @return {string}
 *         Segment url with identifiers replaced
 */

const constructTemplateUrl = (url, values) => url.replace(identifierPattern, identifierReplacement(values));
/**
 * Generates a list of objects containing timing and duration information about each
 * segment needed to generate segment uris and the complete segment object
 *
 * @param {Object} attributes
 *        Object containing all inherited attributes from parent elements with attribute
 *        names as keys
 * @param {Object[]|undefined} segmentTimeline
 *        List of objects representing the attributes of each S element contained within
 *        the SegmentTimeline element
 * @return {{number: number, duration: number, time: number, timeline: number}[]}
 *         List of Objects with segment timing and duration info
 */

const parseTemplateInfo = (attributes, segmentTimeline) => {
  if (!attributes.duration && !segmentTimeline) {
    // if neither @duration or SegmentTimeline are present, then there shall be exactly
    // one media segment
    return [{
      number: attributes.startNumber || 1,
      duration: attributes.sourceDuration,
      time: 0,
      timeline: attributes.periodStart
    }];
  }

  if (attributes.duration) {
    return parseByDuration(attributes);
  }

  return parseByTimeline(attributes, segmentTimeline);
};
/**
 * Generates a list of segments using information provided by the SegmentTemplate element
 *
 * @param {Object} attributes
 *        Object containing all inherited attributes from parent elements with attribute
 *        names as keys
 * @param {Object[]|undefined} segmentTimeline
 *        List of objects representing the attributes of each S element contained within
 *        the SegmentTimeline element
 * @return {Object[]}
 *         List of segment objects
 */

const segmentsFromTemplate = (attributes, segmentTimeline) => {
  const templateValues = {
    RepresentationID: attributes.id,
    Bandwidth: attributes.bandwidth || 0
  };
  const {
    initialization = {
      sourceURL: '',
      range: ''
    }
  } = attributes;
  const mapSegment = urlTypeToSegment({
    baseUrl: attributes.baseUrl,
    source: constructTemplateUrl(initialization.sourceURL, templateValues),
    range: initialization.range
  });
  const segments = parseTemplateInfo(attributes, segmentTimeline);
  return segments.map(segment => {
    templateValues.Number = segment.number;
    templateValues.Time = segment.time;
    const uri = constructTemplateUrl(attributes.media || '', templateValues); // See DASH spec section 5.3.9.2.2
    // - if timescale isn't present on any level, default to 1.

    const timescale = attributes.timescale || 1; // - if presentationTimeOffset isn't present on any level, default to 0

    const presentationTimeOffset = attributes.presentationTimeOffset || 0;
    const presentationTime = // Even if the @t attribute is not specified for the segment, segment.time is
    // calculated in mpd-parser prior to this, so it's assumed to be available.
    attributes.periodStart + (segment.time - presentationTimeOffset) / timescale;
    const map = {
      uri,
      timeline: segment.timeline,
      duration: segment.duration,
      resolvedUri: resolveUrl(attributes.baseUrl || '', uri),
      map: mapSegment,
      number: segment.number,
      presentationTime
    };
    return map;
  });
};

/**
 * Converts a <SegmentUrl> (of type URLType from the DASH spec 5.3.9.2 Table 14)
 * to an object that matches the output of a segment in videojs/mpd-parser
 *
 * @param {Object} attributes
 *   Object containing all inherited attributes from parent elements with attribute
 *   names as keys
 * @param {Object} segmentUrl
 *   <SegmentURL> node to translate into a segment object
 * @return {Object} translated segment object
 */

const SegmentURLToSegmentObject = (attributes, segmentUrl) => {
  const {
    baseUrl,
    initialization = {}
  } = attributes;
  const initSegment = urlTypeToSegment({
    baseUrl,
    source: initialization.sourceURL,
    range: initialization.range
  });
  const segment = urlTypeToSegment({
    baseUrl,
    source: segmentUrl.media,
    range: segmentUrl.mediaRange
  });
  segment.map = initSegment;
  return segment;
};
/**
 * Generates a list of segments using information provided by the SegmentList element
 * SegmentList (DASH SPEC Section 5.3.9.3.2) contains a set of <SegmentURL> nodes.  Each
 * node should be translated into segment.
 *
 * @param {Object} attributes
 *   Object containing all inherited attributes from parent elements with attribute
 *   names as keys
 * @param {Object[]|undefined} segmentTimeline
 *        List of objects representing the attributes of each S element contained within
 *        the SegmentTimeline element
 * @return {Object.<Array>} list of segments
 */


const segmentsFromList = (attributes, segmentTimeline) => {
  const {
    duration,
    segmentUrls = [],
    periodStart
  } = attributes; // Per spec (5.3.9.2.1) no way to determine segment duration OR
  // if both SegmentTimeline and @duration are defined, it is outside of spec.

  if (!duration && !segmentTimeline || duration && segmentTimeline) {
    throw new Error(errors.SEGMENT_TIME_UNSPECIFIED);
  }

  const segmentUrlMap = segmentUrls.map(segmentUrlObject => SegmentURLToSegmentObject(attributes, segmentUrlObject));
  let segmentTimeInfo;

  if (duration) {
    segmentTimeInfo = parseByDuration(attributes);
  }

  if (segmentTimeline) {
    segmentTimeInfo = parseByTimeline(attributes, segmentTimeline);
  }

  const segments = segmentTimeInfo.map((segmentTime, index) => {
    if (segmentUrlMap[index]) {
      const segment = segmentUrlMap[index]; // See DASH spec section 5.3.9.2.2
      // - if timescale isn't present on any level, default to 1.

      const timescale = attributes.timescale || 1; // - if presentationTimeOffset isn't present on any level, default to 0

      const presentationTimeOffset = attributes.presentationTimeOffset || 0;
      segment.timeline = segmentTime.timeline;
      segment.duration = segmentTime.duration;
      segment.number = segmentTime.number;
      segment.presentationTime = periodStart + (segmentTime.time - presentationTimeOffset) / timescale;
      return segment;
    } // Since we're mapping we should get rid of any blank segments (in case
    // the given SegmentTimeline is handling for more elements than we have
    // SegmentURLs for).

  }).filter(segment => segment);
  return segments;
};

const generateSegments = ({
  attributes,
  segmentInfo
}) => {
  let segmentAttributes;
  let segmentsFn;

  if (segmentInfo.template) {
    segmentsFn = segmentsFromTemplate;
    segmentAttributes = merge(attributes, segmentInfo.template);
  } else if (segmentInfo.base) {
    segmentsFn = segmentsFromBase;
    segmentAttributes = merge(attributes, segmentInfo.base);
  } else if (segmentInfo.list) {
    segmentsFn = segmentsFromList;
    segmentAttributes = merge(attributes, segmentInfo.list);
  }

  const segmentsInfo = {
    attributes
  };

  if (!segmentsFn) {
    return segmentsInfo;
  }

  const segments = segmentsFn(segmentAttributes, segmentInfo.segmentTimeline); // The @duration attribute will be used to determin the playlist's targetDuration which
  // must be in seconds. Since we've generated the segment list, we no longer need
  // @duration to be in @timescale units, so we can convert it here.

  if (segmentAttributes.duration) {
    const {
      duration,
      timescale = 1
    } = segmentAttributes;
    segmentAttributes.duration = duration / timescale;
  } else if (segments.length) {
    // if there is no @duration attribute, use the largest segment duration as
    // as target duration
    segmentAttributes.duration = segments.reduce((max, segment) => {
      return Math.max(max, Math.ceil(segment.duration));
    }, 0);
  } else {
    segmentAttributes.duration = 0;
  }

  segmentsInfo.attributes = segmentAttributes;
  segmentsInfo.segments = segments; // This is a sidx box without actual segment information

  if (segmentInfo.base && segmentAttributes.indexRange) {
    segmentsInfo.sidx = segments[0];
    segmentsInfo.segments = [];
  }

  return segmentsInfo;
};
const toPlaylists = representations => representations.map(generateSegments);

const findChildren = (element, name) => from(element.childNodes).filter(({
  tagName
}) => tagName === name);
const getContent = element => element.textContent.trim();

/**
 * Converts the provided string that may contain a division operation to a number.
 *
 * @param {string} value - the provided string value
 *
 * @return {number} the parsed string value
 */
const parseDivisionValue = value => {
  return parseFloat(value.split('/').reduce((prev, current) => prev / current));
};

const parseDuration = str => {
  const SECONDS_IN_YEAR = 365 * 24 * 60 * 60;
  const SECONDS_IN_MONTH = 30 * 24 * 60 * 60;
  const SECONDS_IN_DAY = 24 * 60 * 60;
  const SECONDS_IN_HOUR = 60 * 60;
  const SECONDS_IN_MIN = 60; // P10Y10M10DT10H10M10.1S

  const durationRegex = /P(?:(\d*)Y)?(?:(\d*)M)?(?:(\d*)D)?(?:T(?:(\d*)H)?(?:(\d*)M)?(?:([\d.]*)S)?)?/;
  const match = durationRegex.exec(str);

  if (!match) {
    return 0;
  }

  const [year, month, day, hour, minute, second] = match.slice(1);
  return parseFloat(year || 0) * SECONDS_IN_YEAR + parseFloat(month || 0) * SECONDS_IN_MONTH + parseFloat(day || 0) * SECONDS_IN_DAY + parseFloat(hour || 0) * SECONDS_IN_HOUR + parseFloat(minute || 0) * SECONDS_IN_MIN + parseFloat(second || 0);
};
const parseDate = str => {
  // Date format without timezone according to ISO 8601
  // YYY-MM-DDThh:mm:ss.ssssss
  const dateRegex = /^\d+-\d+-\d+T\d+:\d+:\d+(\.\d+)?$/; // If the date string does not specifiy a timezone, we must specifiy UTC. This is
  // expressed by ending with 'Z'

  if (dateRegex.test(str)) {
    str += 'Z';
  }

  return Date.parse(str);
};

const parsers = {
  /**
   * Specifies the duration of the entire Media Presentation. Format is a duration string
   * as specified in ISO 8601
   *
   * @param {string} value
   *        value of attribute as a string
   * @return {number}
   *         The duration in seconds
   */
  mediaPresentationDuration(value) {
    return parseDuration(value);
  },

  /**
   * Specifies the Segment availability start time for all Segments referred to in this
   * MPD. For a dynamic manifest, it specifies the anchor for the earliest availability
   * time. Format is a date string as specified in ISO 8601
   *
   * @param {string} value
   *        value of attribute as a string
   * @return {number}
   *         The date as seconds from unix epoch
   */
  availabilityStartTime(value) {
    return parseDate(value) / 1000;
  },

  /**
   * Specifies the smallest period between potential changes to the MPD. Format is a
   * duration string as specified in ISO 8601
   *
   * @param {string} value
   *        value of attribute as a string
   * @return {number}
   *         The duration in seconds
   */
  minimumUpdatePeriod(value) {
    return parseDuration(value);
  },

  /**
   * Specifies the suggested presentation delay. Format is a
   * duration string as specified in ISO 8601
   *
   * @param {string} value
   *        value of attribute as a string
   * @return {number}
   *         The duration in seconds
   */
  suggestedPresentationDelay(value) {
    return parseDuration(value);
  },

  /**
   * specifices the type of mpd. Can be either "static" or "dynamic"
   *
   * @param {string} value
   *        value of attribute as a string
   *
   * @return {string}
   *         The type as a string
   */
  type(value) {
    return value;
  },

  /**
   * Specifies the duration of the smallest time shifting buffer for any Representation
   * in the MPD. Format is a duration string as specified in ISO 8601
   *
   * @param {string} value
   *        value of attribute as a string
   * @return {number}
   *         The duration in seconds
   */
  timeShiftBufferDepth(value) {
    return parseDuration(value);
  },

  /**
   * Specifies the PeriodStart time of the Period relative to the availabilityStarttime.
   * Format is a duration string as specified in ISO 8601
   *
   * @param {string} value
   *        value of attribute as a string
   * @return {number}
   *         The duration in seconds
   */
  start(value) {
    return parseDuration(value);
  },

  /**
   * Specifies the width of the visual presentation
   *
   * @param {string} value
   *        value of attribute as a string
   * @return {number}
   *         The parsed width
   */
  width(value) {
    return parseInt(value, 10);
  },

  /**
   * Specifies the height of the visual presentation
   *
   * @param {string} value
   *        value of attribute as a string
   * @return {number}
   *         The parsed height
   */
  height(value) {
    return parseInt(value, 10);
  },

  /**
   * Specifies the bitrate of the representation
   *
   * @param {string} value
   *        value of attribute as a string
   * @return {number}
   *         The parsed bandwidth
   */
  bandwidth(value) {
    return parseInt(value, 10);
  },

  /**
   * Specifies the frame rate of the representation
   *
   * @param {string} value
   *        value of attribute as a string
   * @return {number}
   *         The parsed frame rate
   */
  frameRate(value) {
    return parseDivisionValue(value);
  },

  /**
   * Specifies the number of the first Media Segment in this Representation in the Period
   *
   * @param {string} value
   *        value of attribute as a string
   * @return {number}
   *         The parsed number
   */
  startNumber(value) {
    return parseInt(value, 10);
  },

  /**
   * Specifies the timescale in units per seconds
   *
   * @param {string} value
   *        value of attribute as a string
   * @return {number}
   *         The parsed timescale
   */
  timescale(value) {
    return parseInt(value, 10);
  },

  /**
   * Specifies the presentationTimeOffset.
   *
   * @param {string} value
   *        value of the attribute as a string
   *
   * @return {number}
   *         The parsed presentationTimeOffset
   */
  presentationTimeOffset(value) {
    return parseInt(value, 10);
  },

  /**
   * Specifies the constant approximate Segment duration
   * NOTE: The <Period> element also contains an @duration attribute. This duration
   *       specifies the duration of the Period. This attribute is currently not
   *       supported by the rest of the parser, however we still check for it to prevent
   *       errors.
   *
   * @param {string} value
   *        value of attribute as a string
   * @return {number}
   *         The parsed duration
   */
  duration(value) {
    const parsedValue = parseInt(value, 10);

    if (isNaN(parsedValue)) {
      return parseDuration(value);
    }

    return parsedValue;
  },

  /**
   * Specifies the Segment duration, in units of the value of the @timescale.
   *
   * @param {string} value
   *        value of attribute as a string
   * @return {number}
   *         The parsed duration
   */
  d(value) {
    return parseInt(value, 10);
  },

  /**
   * Specifies the MPD start time, in @timescale units, the first Segment in the series
   * starts relative to the beginning of the Period
   *
   * @param {string} value
   *        value of attribute as a string
   * @return {number}
   *         The parsed time
   */
  t(value) {
    return parseInt(value, 10);
  },

  /**
   * Specifies the repeat count of the number of following contiguous Segments with the
   * same duration expressed by the value of @d
   *
   * @param {string} value
   *        value of attribute as a string
   * @return {number}
   *         The parsed number
   */
  r(value) {
    return parseInt(value, 10);
  },

  /**
   * Specifies the presentationTime.
   *
   * @param {string} value
   *        value of the attribute as a string
   *
   * @return {number}
   *         The parsed presentationTime
   */
  presentationTime(value) {
    return parseInt(value, 10);
  },

  /**
   * Default parser for all other attributes. Acts as a no-op and just returns the value
   * as a string
   *
   * @param {string} value
   *        value of attribute as a string
   * @return {string}
   *         Unparsed value
   */
  DEFAULT(value) {
    return value;
  }

};
/**
 * Gets all the attributes and values of the provided node, parses attributes with known
 * types, and returns an object with attribute names mapped to values.
 *
 * @param {Node} el
 *        The node to parse attributes from
 * @return {Object}
 *         Object with all attributes of el parsed
 */

const parseAttributes = el => {
  if (!(el && el.attributes)) {
    return {};
  }

  return from(el.attributes).reduce((a, e) => {
    const parseFn = parsers[e.name] || parsers.DEFAULT;
    a[e.name] = parseFn(e.value);
    return a;
  }, {});
};

const keySystemsMap = {
  'urn:uuid:1077efec-c0b2-4d02-ace3-3c1e52e2fb4b': 'org.w3.clearkey',
  'urn:uuid:edef8ba9-79d6-4ace-a3c8-27dcd51d21ed': 'com.widevine.alpha',
  'urn:uuid:9a04f079-9840-4286-ab92-e65be0885f95': 'com.microsoft.playready',
  'urn:uuid:f239e769-efa3-4850-9c16-a903c6932efb': 'com.adobe.primetime'
};
/**
 * Builds a list of urls that is the product of the reference urls and BaseURL values
 *
 * @param {string[]} referenceUrls
 *        List of reference urls to resolve to
 * @param {Node[]} baseUrlElements
 *        List of BaseURL nodes from the mpd
 * @return {string[]}
 *         List of resolved urls
 */

const buildBaseUrls = (referenceUrls, baseUrlElements) => {
  if (!baseUrlElements.length) {
    return referenceUrls;
  }

  return flatten(referenceUrls.map(function (reference) {
    return baseUrlElements.map(function (baseUrlElement) {
      return resolveUrl(reference, getContent(baseUrlElement));
    });
  }));
};
/**
 * Contains all Segment information for its containing AdaptationSet
 *
 * @typedef {Object} SegmentInformation
 * @property {Object|undefined} template
 *           Contains the attributes for the SegmentTemplate node
 * @property {Object[]|undefined} segmentTimeline
 *           Contains a list of atrributes for each S node within the SegmentTimeline node
 * @property {Object|undefined} list
 *           Contains the attributes for the SegmentList node
 * @property {Object|undefined} base
 *           Contains the attributes for the SegmentBase node
 */

/**
 * Returns all available Segment information contained within the AdaptationSet node
 *
 * @param {Node} adaptationSet
 *        The AdaptationSet node to get Segment information from
 * @return {SegmentInformation}
 *         The Segment information contained within the provided AdaptationSet
 */

const getSegmentInformation = adaptationSet => {
  const segmentTemplate = findChildren(adaptationSet, 'SegmentTemplate')[0];
  const segmentList = findChildren(adaptationSet, 'SegmentList')[0];
  const segmentUrls = segmentList && findChildren(segmentList, 'SegmentURL').map(s => merge({
    tag: 'SegmentURL'
  }, parseAttributes(s)));
  const segmentBase = findChildren(adaptationSet, 'SegmentBase')[0];
  const segmentTimelineParentNode = segmentList || segmentTemplate;
  const segmentTimeline = segmentTimelineParentNode && findChildren(segmentTimelineParentNode, 'SegmentTimeline')[0];
  const segmentInitializationParentNode = segmentList || segmentBase || segmentTemplate;
  const segmentInitialization = segmentInitializationParentNode && findChildren(segmentInitializationParentNode, 'Initialization')[0]; // SegmentTemplate is handled slightly differently, since it can have both
  // @initialization and an <Initialization> node.  @initialization can be templated,
  // while the node can have a url and range specified.  If the <SegmentTemplate> has
  // both @initialization and an <Initialization> subelement we opt to override with
  // the node, as this interaction is not defined in the spec.

  const template = segmentTemplate && parseAttributes(segmentTemplate);

  if (template && segmentInitialization) {
    template.initialization = segmentInitialization && parseAttributes(segmentInitialization);
  } else if (template && template.initialization) {
    // If it is @initialization we convert it to an object since this is the format that
    // later functions will rely on for the initialization segment.  This is only valid
    // for <SegmentTemplate>
    template.initialization = {
      sourceURL: template.initialization
    };
  }

  const segmentInfo = {
    template,
    segmentTimeline: segmentTimeline && findChildren(segmentTimeline, 'S').map(s => parseAttributes(s)),
    list: segmentList && merge(parseAttributes(segmentList), {
      segmentUrls,
      initialization: parseAttributes(segmentInitialization)
    }),
    base: segmentBase && merge(parseAttributes(segmentBase), {
      initialization: parseAttributes(segmentInitialization)
    })
  };
  Object.keys(segmentInfo).forEach(key => {
    if (!segmentInfo[key]) {
      delete segmentInfo[key];
    }
  });
  return segmentInfo;
};
/**
 * Contains Segment information and attributes needed to construct a Playlist object
 * from a Representation
 *
 * @typedef {Object} RepresentationInformation
 * @property {SegmentInformation} segmentInfo
 *           Segment information for this Representation
 * @property {Object} attributes
 *           Inherited attributes for this Representation
 */

/**
 * Maps a Representation node to an object containing Segment information and attributes
 *
 * @name inheritBaseUrlsCallback
 * @function
 * @param {Node} representation
 *        Representation node from the mpd
 * @return {RepresentationInformation}
 *         Representation information needed to construct a Playlist object
 */

/**
 * Returns a callback for Array.prototype.map for mapping Representation nodes to
 * Segment information and attributes using inherited BaseURL nodes.
 *
 * @param {Object} adaptationSetAttributes
 *        Contains attributes inherited by the AdaptationSet
 * @param {string[]} adaptationSetBaseUrls
 *        Contains list of resolved base urls inherited by the AdaptationSet
 * @param {SegmentInformation} adaptationSetSegmentInfo
 *        Contains Segment information for the AdaptationSet
 * @return {inheritBaseUrlsCallback}
 *         Callback map function
 */

const inheritBaseUrls = (adaptationSetAttributes, adaptationSetBaseUrls, adaptationSetSegmentInfo) => representation => {
  const repBaseUrlElements = findChildren(representation, 'BaseURL');
  const repBaseUrls = buildBaseUrls(adaptationSetBaseUrls, repBaseUrlElements);
  const attributes = merge(adaptationSetAttributes, parseAttributes(representation));
  const representationSegmentInfo = getSegmentInformation(representation);
  return repBaseUrls.map(baseUrl => {
    return {
      segmentInfo: merge(adaptationSetSegmentInfo, representationSegmentInfo),
      attributes: merge(attributes, {
        baseUrl
      })
    };
  });
};
/**
 * Tranforms a series of content protection nodes to
 * an object containing pssh data by key system
 *
 * @param {Node[]} contentProtectionNodes
 *        Content protection nodes
 * @return {Object}
 *        Object containing pssh data by key system
 */

const generateKeySystemInformation = contentProtectionNodes => {
  return contentProtectionNodes.reduce((acc, node) => {
    const attributes = parseAttributes(node); // Although it could be argued that according to the UUID RFC spec the UUID string (a-f chars) should be generated
    // as a lowercase string it also mentions it should be treated as case-insensitive on input. Since the key system
    // UUIDs in the keySystemsMap are hardcoded as lowercase in the codebase there isn't any reason not to do
    // .toLowerCase() on the input UUID string from the manifest (at least I could not think of one).

    if (attributes.schemeIdUri) {
      attributes.schemeIdUri = attributes.schemeIdUri.toLowerCase();
    }

    const keySystem = keySystemsMap[attributes.schemeIdUri];

    if (keySystem) {
      acc[keySystem] = {
        attributes
      };
      const psshNode = findChildren(node, 'cenc:pssh')[0];

      if (psshNode) {
        const pssh = getContent(psshNode);
        acc[keySystem].pssh = pssh && decodeB64ToUint8Array(pssh);
      }
    }

    return acc;
  }, {});
}; // defined in ANSI_SCTE 214-1 2016


const parseCaptionServiceMetadata = service => {
  // 608 captions
  if (service.schemeIdUri === 'urn:scte:dash:cc:cea-608:2015') {
    const values = typeof service.value !== 'string' ? [] : service.value.split(';');
    return values.map(value => {
      let channel;
      let language; // default language to value

      language = value;

      if (/^CC\d=/.test(value)) {
        [channel, language] = value.split('=');
      } else if (/^CC\d$/.test(value)) {
        channel = value;
      }

      return {
        channel,
        language
      };
    });
  } else if (service.schemeIdUri === 'urn:scte:dash:cc:cea-708:2015') {
    const values = typeof service.value !== 'string' ? [] : service.value.split(';');
    return values.map(value => {
      const flags = {
        // service or channel number 1-63
        'channel': undefined,
        // language is a 3ALPHA per ISO 639.2/B
        // field is required
        'language': undefined,
        // BIT 1/0 or ?
        // default value is 1, meaning 16:9 aspect ratio, 0 is 4:3, ? is unknown
        'aspectRatio': 1,
        // BIT 1/0
        // easy reader flag indicated the text is tailed to the needs of beginning readers
        // default 0, or off
        'easyReader': 0,
        // BIT 1/0
        // If 3d metadata is present (CEA-708.1) then 1
        // default 0
        '3D': 0
      };

      if (/=/.test(value)) {
        const [channel, opts = ''] = value.split('=');
        flags.channel = channel;
        flags.language = value;
        opts.split(',').forEach(opt => {
          const [name, val] = opt.split(':');

          if (name === 'lang') {
            flags.language = val; // er for easyReadery
          } else if (name === 'er') {
            flags.easyReader = Number(val); // war for wide aspect ratio
          } else if (name === 'war') {
            flags.aspectRatio = Number(val);
          } else if (name === '3D') {
            flags['3D'] = Number(val);
          }
        });
      } else {
        flags.language = value;
      }

      if (flags.channel) {
        flags.channel = 'SERVICE' + flags.channel;
      }

      return flags;
    });
  }
};
/**
 * A map callback that will parse all event stream data for a collection of periods
 * DASH ISO_IEC_23009 5.10.2.2
 * https://dashif-documents.azurewebsites.net/Events/master/event.html#mpd-event-timing
 *
 * @param {PeriodInformation} period object containing necessary period information
 * @return a collection of parsed eventstream event objects
 */

const toEventStream = period => {
  // get and flatten all EventStreams tags and parse attributes and children
  return flatten(findChildren(period.node, 'EventStream').map(eventStream => {
    const eventStreamAttributes = parseAttributes(eventStream);
    const schemeIdUri = eventStreamAttributes.schemeIdUri; // find all Events per EventStream tag and map to return objects

    return findChildren(eventStream, 'Event').map(event => {
      const eventAttributes = parseAttributes(event);
      const presentationTime = eventAttributes.presentationTime || 0;
      const timescale = eventStreamAttributes.timescale || 1;
      const duration = eventAttributes.duration || 0;
      const start = presentationTime / timescale + period.attributes.start;
      return {
        schemeIdUri,
        value: eventStreamAttributes.value,
        id: eventAttributes.id,
        start,
        end: start + duration / timescale,
        messageData: getContent(event) || eventAttributes.messageData,
        contentEncoding: eventStreamAttributes.contentEncoding,
        presentationTimeOffset: eventStreamAttributes.presentationTimeOffset || 0
      };
    });
  }));
};
/**
 * Maps an AdaptationSet node to a list of Representation information objects
 *
 * @name toRepresentationsCallback
 * @function
 * @param {Node} adaptationSet
 *        AdaptationSet node from the mpd
 * @return {RepresentationInformation[]}
 *         List of objects containing Representaion information
 */

/**
 * Returns a callback for Array.prototype.map for mapping AdaptationSet nodes to a list of
 * Representation information objects
 *
 * @param {Object} periodAttributes
 *        Contains attributes inherited by the Period
 * @param {string[]} periodBaseUrls
 *        Contains list of resolved base urls inherited by the Period
 * @param {string[]} periodSegmentInfo
 *        Contains Segment Information at the period level
 * @return {toRepresentationsCallback}
 *         Callback map function
 */

const toRepresentations = (periodAttributes, periodBaseUrls, periodSegmentInfo) => adaptationSet => {
  const adaptationSetAttributes = parseAttributes(adaptationSet);
  const adaptationSetBaseUrls = buildBaseUrls(periodBaseUrls, findChildren(adaptationSet, 'BaseURL'));
  const role = findChildren(adaptationSet, 'Role')[0];
  const roleAttributes = {
    role: parseAttributes(role)
  };
  let attrs = merge(periodAttributes, adaptationSetAttributes, roleAttributes);
  const accessibility = findChildren(adaptationSet, 'Accessibility')[0];
  const captionServices = parseCaptionServiceMetadata(parseAttributes(accessibility));

  if (captionServices) {
    attrs = merge(attrs, {
      captionServices
    });
  }

  const label = findChildren(adaptationSet, 'Label')[0];

  if (label && label.childNodes.length) {
    const labelVal = label.childNodes[0].nodeValue.trim();
    attrs = merge(attrs, {
      label: labelVal
    });
  }

  const contentProtection = generateKeySystemInformation(findChildren(adaptationSet, 'ContentProtection'));

  if (Object.keys(contentProtection).length) {
    attrs = merge(attrs, {
      contentProtection
    });
  }

  const segmentInfo = getSegmentInformation(adaptationSet);
  const representations = findChildren(adaptationSet, 'Representation');
  const adaptationSetSegmentInfo = merge(periodSegmentInfo, segmentInfo);
  return flatten(representations.map(inheritBaseUrls(attrs, adaptationSetBaseUrls, adaptationSetSegmentInfo)));
};
/**
 * Contains all period information for mapping nodes onto adaptation sets.
 *
 * @typedef {Object} PeriodInformation
 * @property {Node} period.node
 *           Period node from the mpd
 * @property {Object} period.attributes
 *           Parsed period attributes from node plus any added
 */

/**
 * Maps a PeriodInformation object to a list of Representation information objects for all
 * AdaptationSet nodes contained within the Period.
 *
 * @name toAdaptationSetsCallback
 * @function
 * @param {PeriodInformation} period
 *        Period object containing necessary period information
 * @param {number} periodStart
 *        Start time of the Period within the mpd
 * @return {RepresentationInformation[]}
 *         List of objects containing Representaion information
 */

/**
 * Returns a callback for Array.prototype.map for mapping Period nodes to a list of
 * Representation information objects
 *
 * @param {Object} mpdAttributes
 *        Contains attributes inherited by the mpd
 * @param {string[]} mpdBaseUrls
 *        Contains list of resolved base urls inherited by the mpd
 * @return {toAdaptationSetsCallback}
 *         Callback map function
 */

const toAdaptationSets = (mpdAttributes, mpdBaseUrls) => (period, index) => {
  const periodBaseUrls = buildBaseUrls(mpdBaseUrls, findChildren(period.node, 'BaseURL'));
  const periodAttributes = merge(mpdAttributes, {
    periodStart: period.attributes.start
  });

  if (typeof period.attributes.duration === 'number') {
    periodAttributes.periodDuration = period.attributes.duration;
  }

  const adaptationSets = findChildren(period.node, 'AdaptationSet');
  const periodSegmentInfo = getSegmentInformation(period.node);
  return flatten(adaptationSets.map(toRepresentations(periodAttributes, periodBaseUrls, periodSegmentInfo)));
};
/**
 * Gets Period@start property for a given period.
 *
 * @param {Object} options
 *        Options object
 * @param {Object} options.attributes
 *        Period attributes
 * @param {Object} [options.priorPeriodAttributes]
 *        Prior period attributes (if prior period is available)
 * @param {string} options.mpdType
 *        The MPD@type these periods came from
 * @return {number|null}
 *         The period start, or null if it's an early available period or error
 */

const getPeriodStart = ({
  attributes,
  priorPeriodAttributes,
  mpdType
}) => {
  // Summary of period start time calculation from DASH spec section 5.3.2.1
  //
  // A period's start is the first period's start + time elapsed after playing all
  // prior periods to this one. Periods continue one after the other in time (without
  // gaps) until the end of the presentation.
  //
  // The value of Period@start should be:
  // 1. if Period@start is present: value of Period@start
  // 2. if previous period exists and it has @duration: previous Period@start +
  //    previous Period@duration
  // 3. if this is first period and MPD@type is 'static': 0
  // 4. in all other cases, consider the period an "early available period" (note: not
  //    currently supported)
  // (1)
  if (typeof attributes.start === 'number') {
    return attributes.start;
  } // (2)


  if (priorPeriodAttributes && typeof priorPeriodAttributes.start === 'number' && typeof priorPeriodAttributes.duration === 'number') {
    return priorPeriodAttributes.start + priorPeriodAttributes.duration;
  } // (3)


  if (!priorPeriodAttributes && mpdType === 'static') {
    return 0;
  } // (4)
  // There is currently no logic for calculating the Period@start value if there is
  // no Period@start or prior Period@start and Period@duration available. This is not made
  // explicit by the DASH interop guidelines or the DASH spec, however, since there's
  // nothing about any other resolution strategies, it's implied. Thus, this case should
  // be considered an early available period, or error, and null should suffice for both
  // of those cases.


  return null;
};
/**
 * Traverses the mpd xml tree to generate a list of Representation information objects
 * that have inherited attributes from parent nodes
 *
 * @param {Node} mpd
 *        The root node of the mpd
 * @param {Object} options
 *        Available options for inheritAttributes
 * @param {string} options.manifestUri
 *        The uri source of the mpd
 * @param {number} options.NOW
 *        Current time per DASH IOP.  Default is current time in ms since epoch
 * @param {number} options.clientOffset
 *        Client time difference from NOW (in milliseconds)
 * @return {RepresentationInformation[]}
 *         List of objects containing Representation information
 */

const inheritAttributes = (mpd, options = {}) => {
  const {
    manifestUri = '',
    NOW = Date.now(),
    clientOffset = 0
  } = options;
  const periodNodes = findChildren(mpd, 'Period');

  if (!periodNodes.length) {
    throw new Error(errors.INVALID_NUMBER_OF_PERIOD);
  }

  const locations = findChildren(mpd, 'Location');
  const mpdAttributes = parseAttributes(mpd);
  const mpdBaseUrls = buildBaseUrls([manifestUri], findChildren(mpd, 'BaseURL')); // See DASH spec section 5.3.1.2, Semantics of MPD element. Default type to 'static'.

  mpdAttributes.type = mpdAttributes.type || 'static';
  mpdAttributes.sourceDuration = mpdAttributes.mediaPresentationDuration || 0;
  mpdAttributes.NOW = NOW;
  mpdAttributes.clientOffset = clientOffset;

  if (locations.length) {
    mpdAttributes.locations = locations.map(getContent);
  }

  const periods = []; // Since toAdaptationSets acts on individual periods right now, the simplest approach to
  // adding properties that require looking at prior periods is to parse attributes and add
  // missing ones before toAdaptationSets is called. If more such properties are added, it
  // may be better to refactor toAdaptationSets.

  periodNodes.forEach((node, index) => {
    const attributes = parseAttributes(node); // Use the last modified prior period, as it may contain added information necessary
    // for this period.

    const priorPeriod = periods[index - 1];
    attributes.start = getPeriodStart({
      attributes,
      priorPeriodAttributes: priorPeriod ? priorPeriod.attributes : null,
      mpdType: mpdAttributes.type
    });
    periods.push({
      node,
      attributes
    });
  });
  return {
    locations: mpdAttributes.locations,
    representationInfo: flatten(periods.map(toAdaptationSets(mpdAttributes, mpdBaseUrls))),
    eventStream: flatten(periods.map(toEventStream))
  };
};

const stringToMpdXml = manifestString => {
  if (manifestString === '') {
    throw new Error(errors.DASH_EMPTY_MANIFEST);
  }

  const parser = new DOMParser();
  let xml;
  let mpd;

  try {
    xml = parser.parseFromString(manifestString, 'application/xml');
    mpd = xml && xml.documentElement.tagName === 'MPD' ? xml.documentElement : null;
  } catch (e) {// ie 11 throwsw on invalid xml
  }

  if (!mpd || mpd && mpd.getElementsByTagName('parsererror').length > 0) {
    throw new Error(errors.DASH_INVALID_XML);
  }

  return mpd;
};

/**
 * Parses the manifest for a UTCTiming node, returning the nodes attributes if found
 *
 * @param {string} mpd
 *        XML string of the MPD manifest
 * @return {Object|null}
 *         Attributes of UTCTiming node specified in the manifest. Null if none found
 */

const parseUTCTimingScheme = mpd => {
  const UTCTimingNode = findChildren(mpd, 'UTCTiming')[0];

  if (!UTCTimingNode) {
    return null;
  }

  const attributes = parseAttributes(UTCTimingNode);

  switch (attributes.schemeIdUri) {
    case 'urn:mpeg:dash:utc:http-head:2014':
    case 'urn:mpeg:dash:utc:http-head:2012':
      attributes.method = 'HEAD';
      break;

    case 'urn:mpeg:dash:utc:http-xsdate:2014':
    case 'urn:mpeg:dash:utc:http-iso:2014':
    case 'urn:mpeg:dash:utc:http-xsdate:2012':
    case 'urn:mpeg:dash:utc:http-iso:2012':
      attributes.method = 'GET';
      break;

    case 'urn:mpeg:dash:utc:direct:2014':
    case 'urn:mpeg:dash:utc:direct:2012':
      attributes.method = 'DIRECT';
      attributes.value = Date.parse(attributes.value);
      break;

    case 'urn:mpeg:dash:utc:http-ntp:2014':
    case 'urn:mpeg:dash:utc:ntp:2014':
    case 'urn:mpeg:dash:utc:sntp:2014':
    default:
      throw new Error(errors.UNSUPPORTED_UTC_TIMING_SCHEME);
  }

  return attributes;
};

const VERSION = version;
/*
 * Given a DASH manifest string and options, parses the DASH manifest into an object in the
 * form outputed by m3u8-parser and accepted by videojs/http-streaming.
 *
 * For live DASH manifests, if `previousManifest` is provided in options, then the newly
 * parsed DASH manifest will have its media sequence and discontinuity sequence values
 * updated to reflect its position relative to the prior manifest.
 *
 * @param {string} manifestString - the DASH manifest as a string
 * @param {options} [options] - any options
 *
 * @return {Object} the manifest object
 */

const parse = (manifestString, options = {}) => {
  const parsedManifestInfo = inheritAttributes(stringToMpdXml(manifestString), options);
  const playlists = toPlaylists(parsedManifestInfo.representationInfo);
  return toM3u8({
    dashPlaylists: playlists,
    locations: parsedManifestInfo.locations,
    sidxMapping: options.sidxMapping,
    previousManifest: options.previousManifest,
    eventStream: parsedManifestInfo.eventStream
  });
};
/**
 * Parses the manifest for a UTCTiming node, returning the nodes attributes if found
 *
 * @param {string} manifestString
 *        XML string of the MPD manifest
 * @return {Object|null}
 *         Attributes of UTCTiming node specified in the manifest. Null if none found
 */


const parseUTCTiming = manifestString => parseUTCTimingScheme(stringToMpdXml(manifestString));

export { VERSION, addSidxSegmentsToPlaylist$1 as addSidxSegmentsToPlaylist, generateSidxKey, inheritAttributes, parse, parseUTCTiming, stringToMpdXml, toM3u8, toPlaylists };