feat: limited multiperiod support (#35)

src/inheritAttributes.js

@@ -1,3 +1,4 @@
+import window from 'global/window';
 import { flatten } from './utils/list';
 import { merge } from './utils/object';
 import { findChildren, getContent } from './utils/xml';
@@ -269,8 +270,12 @@ export const toRepresentations =
  * @return {toAdaptationSetsCallback}
  *         Callback map function
  */
-export const toAdaptationSets = (mpdAttributes, mpdBaseUrls) => (period, periodIndex) => {
+export const toAdaptationSets = (mpdAttributes, mpdBaseUrls) => (period, index) => {
   const periodBaseUrls = buildBaseUrls(mpdBaseUrls, findChildren(period, 'BaseURL'));
+  const periodAtt = parseAttributes(period);
+  const parsedPeriodId = parseInt(periodAtt.id, 10);
+  // fallback to mapping index if Period@id is not a number
+  const periodIndex = window.isNaN(parsedPeriodId) ? index : parsedPeriodId;
   const periodAttributes = merge(mpdAttributes, { periodIndex });
   const adaptationSets = findChildren(period, 'AdaptationSet');
   const periodSegmentInfo = getSegmentInformation(period);
@@ -304,8 +309,7 @@ export const inheritAttributes = (mpd, options = {}) => {
   } = options;
   const periods = findChildren(mpd, 'Period');
 
-  if (periods.length !== 1) {
-    // TODO add support for multiperiod
+  if (!periods.length) {
     throw new Error(errors.INVALID_NUMBER_OF_PERIOD);
   }
 

src/toM3u8.js

@@ -1,3 +1,41 @@
+import { values } from './utils/object';
+import { findIndexes } from './utils/list';
+
+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 || '');
+
+    // Periods after first
+    if (acc[name]) {
+      // first segment of subsequent periods signal a discontinuity
+      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;
+      }
+    } else {
+      // first Period
+      acc[name] = playlist;
+    }
+
+    return acc;
+  }, {}));
+
+  return mergedPlaylists.map(playlist => {
+    playlist.discontinuityStarts =
+        findIndexes(playlist.segments, 'discontinuity');
+
+    return playlist;
+  });
+};
+
 export const formatAudioPlaylist = ({ attributes, segments }) => {
   const playlist = {
     attributes: {
@@ -151,8 +189,10 @@ export const toM3u8 = dashPlaylists => {
   const vttOnly = ({ attributes }) =>
     attributes.mimeType === 'text/vtt' || attributes.contentType === 'text';
 
-  const videoPlaylists = dashPlaylists.filter(videoOnly).map(formatVideoPlaylist);
-  const audioPlaylists = dashPlaylists.filter(audioOnly);
+  const videoPlaylists = mergeDiscontiguousPlaylists(
+    dashPlaylists.filter(videoOnly)
+  ).map(formatVideoPlaylist);
+  const audioPlaylists = mergeDiscontiguousPlaylists(dashPlaylists.filter(audioOnly));
   const vttPlaylists = dashPlaylists.filter(vttOnly);
 
   const master = {

src/utils/list.js

@@ -23,3 +23,11 @@ export const from = list => {
 
   return result;
 };
+
+export const findIndexes = (l, key) => l.reduce((a, e, i) => {
+  if (e[key]) {
+    a.push(i);
+  }
+
+  return a;
+}, []);

src/utils/object.js

@@ -19,3 +19,5 @@ export const merge = (...objects) => {
     return result;
   }, {});
 };
+
+export const values = o => Object.keys(o).map(k => o[k]);

test/index.test.js

@@ -5,6 +5,7 @@ import QUnit from 'qunit';
 import maatVttSegmentTemplate from './manifests/maat_vtt_segmentTemplate.mpd';
 import segmentBaseTemplate from './manifests/segmentBase.mpd';
 import segmentListTemplate from './manifests/segmentList.mpd';
+import multiperiod from './manifests/multiperiod.mpd';
 import {
   parsedManifest as maatVttSegmentTemplateManifest
 } from './manifests/maat_vtt_segmentTemplate.js';
@@ -14,6 +15,10 @@ import {
 import {
   parsedManifest as segmentListManifest
 } from './manifests/segmentList.js';
+import {
+  parsedManifest as multiperiodManifest
+} from './manifests/multiperiod.js';
+
 QUnit.module('mpd-parser');
 
 QUnit.test('has VERSION', function(assert) {
@@ -36,6 +41,10 @@ QUnit.test('has parse', function(assert) {
   name: 'segmentList',
   input: segmentListTemplate,
   expected: segmentListManifest
+}, {
+  name: 'multiperiod',
+  input: multiperiod,
+  expected: multiperiodManifest
 }].forEach(({ name, input, expected }) => {
   QUnit.test(`${name} test manifest`, function(assert) {
     const actual = parse(input);