feat: add sidx information to segment base playlists (#41)

package.json

@@ -1,6 +1,6 @@
 {
   "name": "mpd-parser",
-  "version": "0.7.0",
+  "version": "0.8.0-0",
   "description": "mpd parser",
   "main": "dist/mpd-parser.cjs.js",
   "module": "dist/mpd-parser.es.js",

src/index.js

@@ -7,8 +7,8 @@ import { parseUTCTimingScheme } from './parseUTCTimingScheme';
 
 export const VERSION = version;
 
-export const parse = (manifestString, options) =>
-  toM3u8(toPlaylists(inheritAttributes(stringToMpdXml(manifestString), options)));
+export const parse = (manifestString, options = {}) =>
+  toM3u8(toPlaylists(inheritAttributes(stringToMpdXml(manifestString), options)), options.sidxMapping);
 
 /**
  * Parses the manifest for a UTCTiming node, returning the nodes attributes if found

src/segment/segmentBase.js

@@ -32,7 +32,8 @@ export const segmentsFromBase = (attributes) => {
     source: initialization.sourceURL,
     range: initialization.range
   });
-  const segment = urlTypeConverter({ baseUrl, source: baseUrl, range: indexRange });
+
+  const segment = urlTypeConverter({ baseUrl, source: baseUrl, indexRange });
 
   segment.map = initSegment;
 
@@ -55,3 +56,69 @@ export const segmentsFromBase = (attributes) => {
 
   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
+ */
+export const addSegmentsToPlaylist = (playlist, sidx, baseUrl) => {
+  // Retain init segment information
+  const initSegment = playlist.sidx.map ? playlist.sidx.map : null;
+  // Retain source duration from initial master 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 = [];
+
+  // firstOffset is the offset from the end of the sidx box
+  let 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
+    const endIndex = startIndex + size - 1;
+    const indexRange = `${startIndex}-${endIndex}`;
+
+    const attributes = {
+      baseUrl,
+      timescale,
+      timeline,
+      // this is used in parseByDuration
+      periodIndex: timeline,
+      duration,
+      sourceDuration,
+      indexRange
+    };
+
+    const segment = segmentsFromBase(attributes)[0];
+
+    if (initSegment) {
+      segment.map = initSegment;
+    }
+
+    segments.push(segment);
+    startIndex += size;
+  }
+
+  playlist.segments = segments;
+
+  return playlist;
+};

src/segment/urlType.js

@@ -25,26 +25,35 @@ import resolveUrl from '../utils/resolveUrl';
  * @return {SingleUri} full segment information transformed into a format similar
  *   to m3u8-parser
  */
-export const urlTypeToSegment = ({ baseUrl = '', source = '', range = '' }) => {
-  const init = {
+export const urlTypeToSegment = ({ baseUrl = '', source = '', range = '', indexRange = '' }) => {
+  const segment = {
     uri: source,
     resolvedUri: resolveUrl(baseUrl || '', source)
   };
 
-  if (range) {
-    const ranges = range.split('-');
+  if (range || indexRange) {
+    const rangeStr = range ? range : indexRange;
+    const ranges = rangeStr.split('-');
     const startRange = parseInt(ranges[0], 10);
     const endRange = parseInt(ranges[1], 10);
 
     // byterange should be inclusive according to
     // RFC 2616, Clause 14.35.1
-    init.byterange = {
+    segment.byterange = {
       length: endRange - startRange + 1,
       offset: startRange
     };
   }
 
-  return init;
+  return segment;
+};
+
+export const byteRangeToString = (byterange) => {
+  // `endRange` is one less than `offset + length` because the HTTP range
+  // header uses inclusive ranges
+  const endRange = byterange.offset + byterange.length - 1;
+
+  return `${byterange.offset}-${endRange}`;
 };
 
 export default urlTypeToSegment;

src/toM3u8.js

@@ -1,5 +1,7 @@
 import { values } from './utils/object';
 import { findIndexes } from './utils/list';
+import { addSegmentsToPlaylist } from './segment/segmentBase';
+import { byteRangeToString } from './segment/urlType';
 
 const mergeDiscontiguousPlaylists = playlists => {
   const mergedPlaylists = values(playlists.reduce((acc, playlist) => {
@@ -11,7 +13,9 @@ const mergeDiscontiguousPlaylists = playlists => {
     // Periods after first
     if (acc[name]) {
       // first segment of subsequent periods signal a discontinuity
-      playlist.segments[0].discontinuity = true;
+      if (playlist.segments[0]) {
+        playlist.segments[0].discontinuity = true;
+      }
       acc[name].segments.push(...playlist.segments);
 
       // bubble up contentProtection, this assumes all DRM content
@@ -36,7 +40,26 @@ const mergeDiscontiguousPlaylists = playlists => {
   });
 };
 
-export const formatAudioPlaylist = ({ attributes, segments }) => {
+const addSegmentInfoFromSidx = (playlists, sidxMapping = {}) => {
+  if (!Object.keys(sidxMapping).length) {
+    return playlists;
+  }
+
+  for (const i in playlists) {
+    const playlist = playlists[i];
+    const sidxKey = playlist.sidx.uri + '-' +
+      byteRangeToString(playlist.sidx.byterange);
+    const sidxMatch = sidxMapping[sidxKey] && sidxMapping[sidxKey].sidx;
+
+    if (playlist.sidx && sidxMatch) {
+      addSegmentsToPlaylist(playlist, sidxMatch, playlist.sidx.resolvedUri);
+    }
+  }
+
+  return playlists;
+};
+
+export const formatAudioPlaylist = ({ attributes, segments, sidx }) => {
   const playlist = {
     attributes: {
       NAME: attributes.id,
@@ -57,6 +80,10 @@ export const formatAudioPlaylist = ({ attributes, segments }) => {
     playlist.contentProtection = attributes.contentProtection;
   }
 
+  if (sidx) {
+    playlist.sidx = sidx;
+  }
+
   return playlist;
 };
 
@@ -89,16 +116,20 @@ export const formatVttPlaylist = ({ attributes, segments }) => {
   };
 };
 
-export const organizeAudioPlaylists = playlists => {
-  return playlists.reduce((a, playlist) => {
+export const organizeAudioPlaylists = (playlists, sidxMapping = {}) => {
+  let mainPlaylist;
+
+  const formattedPlaylists = playlists.reduce((a, playlist) => {
     const role = playlist.attributes.role &&
-      playlist.attributes.role.value || 'main';
+      playlist.attributes.role.value || '';
     const language = playlist.attributes.lang || '';
 
     let label = 'main';
 
     if (language) {
-      label = `${playlist.attributes.lang} (${role})`;
+      const roleLabel = role ? ` (${role})` : '';
+
+      label = `${playlist.attributes.lang}${roleLabel}`;
     }
 
     // skip if we already have the highest quality audio for a language
@@ -112,15 +143,32 @@ export const organizeAudioPlaylists = playlists => {
       language,
       autoselect: true,
       default: role === 'main',
-      playlists: [formatAudioPlaylist(playlist)],
+      playlists: addSegmentInfoFromSidx(
+        [formatAudioPlaylist(playlist)],
+        sidxMapping
+      ),
       uri: ''
     };
 
+    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;
 };
 
-export const organizeVttPlaylists = playlists => {
+export const organizeVttPlaylists = (playlists, sidxMapping = {}) => {
   return playlists.reduce((a, playlist) => {
     const label = playlist.attributes.lang || 'text';
 
@@ -133,15 +181,18 @@ export const organizeVttPlaylists = playlists => {
       language: label,
       default: false,
       autoselect: false,
-      playlists: [formatVttPlaylist(playlist)],
+      playlists: addSegmentInfoFromSidx(
+        [formatVttPlaylist(playlist)],
+        sidxMapping
+      ),
       uri: ''
     };
 
     return a;
   }, {});
 };
 
-export const formatVideoPlaylist = ({ attributes, segments }) => {
+export const formatVideoPlaylist = ({ attributes, segments, sidx }) => {
   const playlist = {
     attributes: {
       NAME: attributes.id,
@@ -168,10 +219,14 @@ export const formatVideoPlaylist = ({ attributes, segments }) => {
     playlist.contentProtection = attributes.contentProtection;
   }
 
+  if (sidx) {
+    playlist.sidx = sidx;
+  }
+
   return playlist;
 };
 
-export const toM3u8 = dashPlaylists => {
+export const toM3u8 = (dashPlaylists, sidxMapping = {}) => {
   if (!dashPlaylists.length) {
     return {};
   }
@@ -208,16 +263,16 @@ export const toM3u8 = dashPlaylists => {
     },
     uri: '',
     duration,
-    playlists: videoPlaylists,
+    playlists: addSegmentInfoFromSidx(videoPlaylists, sidxMapping),
     minimumUpdatePeriod: minimumUpdatePeriod * 1000
   };
 
   if (audioPlaylists.length) {
-    master.mediaGroups.AUDIO.audio = organizeAudioPlaylists(audioPlaylists);
+    master.mediaGroups.AUDIO.audio = organizeAudioPlaylists(audioPlaylists, sidxMapping);
   }
 
   if (vttPlaylists.length) {
-    master.mediaGroups.SUBTITLES.subs = organizeVttPlaylists(vttPlaylists);
+    master.mediaGroups.SUBTITLES.subs = organizeVttPlaylists(vttPlaylists, sidxMapping);
   }
 
   return master;

src/toPlaylists.js

@@ -18,8 +18,12 @@ export const generateSegments = ({ attributes, segmentInfo }) => {
     segmentAttributes = merge(attributes, segmentInfo.list);
   }
 
+  const segmentsInfo = {
+    attributes
+  };
+
   if (!segmentsFn) {
-    return { attributes };
+    return segmentsInfo;
   }
 
   const segments = segmentsFn(segmentAttributes, segmentInfo.timeline);
@@ -41,10 +45,16 @@ export const generateSegments = ({ attributes, segmentInfo }) => {
     segmentAttributes.duration = 0;
   }
 
-  return {
-    attributes: segmentAttributes,
-    segments
-  };
+  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;
 };
 
 export const toPlaylists = (representations) => representations.map(generateSegments);

test/manifests/maat_vtt_segmentTemplate.js

@@ -76,9 +76,9 @@ export const parsedManifest = {
           }],
           uri: ''
         },
-        ['es (main)']: {
+        ['es']: {
           autoselect: true,
-          default: true,
+          default: false,
           language: 'es',
           playlists: [{
             attributes: {