feat: use new mpd-parser API for handling live DASH refreshes (#1231)

In order to support the new mpd-parser API, whenever a DASH manifest
refreshes, the prior parsed manifest object needs to be passed in as
`previousManifest`. This change adds support for that.

package.json

@@ -60,7 +60,7 @@
  "aes-decrypter": "3.1.2",
  "global": "^4.4.0",
  "m3u8-parser": "4.7.0",
- "mpd-parser": "0.20.0",
+ "mpd-parser": "0.21.0",
  "mux.js": "6.0.0",
  "video.js": "^6 || ^7"
  },

src/dash-playlist-loader.js

@@ -101,16 +101,23 @@ const dashPlaylistUnchanged = function(a, b) {
  * @return {Object}
  * The parsed mpd manifest object
  */
-export const parseMasterXml = ({ masterXml, srcUrl, clientOffset, sidxMapping }) => {
- const master = parseMpd(masterXml, {
+export const parseMasterXml = ({
+ masterXml,
+ srcUrl,
+ clientOffset,
+ sidxMapping,
+ previousManifest
+}) => {
+ const manifest = parseMpd(masterXml, {
  manifestUri: srcUrl,
  clientOffset,
- sidxMapping
+ sidxMapping,
+ previousManifest
  });
 
- addPropertiesToMaster(master, srcUrl);
+ addPropertiesToMaster(manifest, srcUrl);
 
- return master;
+ return manifest;
 };
 
 /**
@@ -130,7 +137,8 @@ export const updateMaster = (oldMaster, newMaster, sidxMapping) => {
  let update = mergeOptions(oldMaster, {
  // These are top level properties that can be updated
  duration: newMaster.duration,
- minimumUpdatePeriod: newMaster.minimumUpdatePeriod
+ minimumUpdatePeriod: newMaster.minimumUpdatePeriod,
+ timelineStarts: newMaster.timelineStarts
  });
 
  // First update the playlists in playlist list
@@ -699,13 +707,15 @@ export default class DashPlaylistLoader extends EventTarget {
  // clear media request
  this.mediaRequest_ = null;
 
+ const oldMaster = this.masterPlaylistLoader_.master;
+
  let newMaster = parseMasterXml({
  masterXml: this.masterPlaylistLoader_.masterXml_,
  srcUrl: this.masterPlaylistLoader_.srcUrl,
  clientOffset: this.masterPlaylistLoader_.clientOffset_,
- sidxMapping: this.masterPlaylistLoader_.sidxMapping_
+ sidxMapping: this.masterPlaylistLoader_.sidxMapping_,
+ previousManifest: oldMaster
  });
- const oldMaster = this.masterPlaylistLoader_.master;
 
  // if we have an old master to compare the new master against
  if (oldMaster) {

test/dash-playlist-loader.test.js

@@ -72,7 +72,8 @@ QUnit.test('updateMaster: returns falsy when there are no changes', function(ass
  SUBTITLES: {}
  },
  duration: 0,
- minimumUpdatePeriod: 0
+ minimumUpdatePeriod: 0,
+ timelineStarts: []
  };
 
  assert.deepEqual(updateMaster(master, master), null);
@@ -94,7 +95,8 @@ QUnit.test('updateMaster: updates playlists', function(assert) {
  SUBTITLES: {}
  },
  duration: 0,
- minimumUpdatePeriod: 0
+ minimumUpdatePeriod: 0,
+ timelineStarts: []
  };
 
  // Only the first playlist is changed
@@ -114,7 +116,8 @@ QUnit.test('updateMaster: updates playlists', function(assert) {
  SUBTITLES: {}
  },
  duration: 0,
- minimumUpdatePeriod: 0
+ minimumUpdatePeriod: 0,
+ timelineStarts: []
  };
 
  assert.deepEqual(
@@ -135,7 +138,8 @@ QUnit.test('updateMaster: updates playlists', function(assert) {
  SUBTITLES: {}
  },
  duration: 0,
- minimumUpdatePeriod: 0
+ minimumUpdatePeriod: 0,
+ timelineStarts: []
  }
  );
 });
@@ -209,6 +213,7 @@ QUnit.test('updateMaster: updates playlists and mediaGroups', function(assert) {
  const master = {
  duration: 10,
  minimumUpdatePeriod: 0,
+ timelineStarts: [],
  mediaGroups: {
  AUDIO: {
  audio: {
@@ -247,6 +252,7 @@ QUnit.test('updateMaster: updates playlists and mediaGroups', function(assert) {
  const update = {
  duration: 20,
  minimumUpdatePeriod: 0,
+ timelineStarts: [],
  mediaGroups: {
  AUDIO: {
  audio: {
@@ -291,6 +297,7 @@ QUnit.test('updateMaster: updates playlists and mediaGroups', function(assert) {
  {
  duration: 20,
  minimumUpdatePeriod: 0,
+ timelineStarts: [],
  mediaGroups: {
  AUDIO: {
  audio: {
@@ -345,7 +352,8 @@ QUnit.test('updateMaster: updates minimumUpdatePeriod', function(assert) {
  SUBTITLES: {}
  },
  duration: 0,
- minimumUpdatePeriod: 0
+ minimumUpdatePeriod: 0,
+ timelineStarts: []
  };
 
  const update = {
@@ -362,7 +370,8 @@ QUnit.test('updateMaster: updates minimumUpdatePeriod', function(assert) {
  SUBTITLES: {}
  },
  duration: 0,
- minimumUpdatePeriod: 2
+ minimumUpdatePeriod: 2,
+ timelineStarts: []
  };
 
  assert.deepEqual(
@@ -381,7 +390,8 @@ QUnit.test('updateMaster: updates minimumUpdatePeriod', function(assert) {
  SUBTITLES: {}
  },
  duration: 0,
- minimumUpdatePeriod: 2
+ minimumUpdatePeriod: 2,
+ timelineStarts: []
  }
  );
 });
@@ -1495,7 +1505,9 @@ QUnit.test('parseMasterXml: includes sidx info if available and matches playlist
 });
 
 QUnit.test('refreshMedia: updates master and media playlists for master loader', function(assert) {
- const loader = new DashPlaylistLoader('dash.mpd', this.fakeVhs);
+ // start at 4 seconds past epoch for 2x 2 second segments
+ this.clock.tick(4 * 1000);
+ const loader = new DashPlaylistLoader('dash-live.mpd', this.fakeVhs);
  let loadedPlaylists = 0;
  let playlistUnchanged = 0;
 
@@ -1519,10 +1531,12 @@ QUnit.test('refreshMedia: updates master and media playlists for master loader',
  });
 
  const oldMaster = loader.master;
- const newMasterXml = testDataManifests['dash-live'];
 
- loader.masterXml_ = newMasterXml;
- loader.refreshMedia_(loader.media().id);
+ // Two seconds later in wall clock should mean one more segment added to ensure the
+ // refresh represents a change. Although four seconds is the minimumUpdatePeriod, since
+ // segments are two seconds in duration, the refreshDelay will be calculated as two
+ // seconds.
+ this.clock.tick(2 * 1000);
 
  assert.notEqual(loader.master, oldMaster, 'new master set');
  assert.strictEqual(loadedPlaylists, 1, 'one loadedplaylist');
@@ -1569,7 +1583,9 @@ QUnit.test('refreshMedia: triggers playlistunchanged for master loader' +
 });
 
 QUnit.test('refreshMedia: updates master and media playlists for child loader', function(assert) {
- const loader = new DashPlaylistLoader('dash.mpd', this.fakeVhs);
+ // start at 4 seconds past epoch for 2x 2 second segments
+ this.clock.tick(4 * 1000);
+ const loader = new DashPlaylistLoader('dash-live.mpd', this.fakeVhs);
  let loadedPlaylists = 0;
  let playlistUnchanged = 0;
 
@@ -1595,11 +1611,12 @@ QUnit.test('refreshMedia: updates master and media playlists for child loader',
  });
 
  const oldMaster = loader.master;
- const newMasterXml = testDataManifests['dash-live'];
 
- loader.masterXml_ = newMasterXml;
- loader.handleMaster_();
- childLoader.refreshMedia_(loader.media().id);
+ // Two seconds later in wall clock should mean one more segment added to ensure the
+ // refresh represents a change. Although four seconds is the minimumUpdatePeriod, since
+ // segments are two seconds in duration, the refreshDelay will be calculated as two
+ // seconds.
+ this.clock.tick(2 * 1000);
 
  assert.notEqual(loader.master, oldMaster, 'new master set on master loader');
  assert.strictEqual(loadedPlaylists, 1, 'one loadedplaylist');
@@ -1658,8 +1675,7 @@ QUnit.test('refreshXml_: requests the sidx if it changed', function(assert) {
  loader.load();
  // initial manifest
  this.standardXHRResponse(this.requests.shift());
- // child playlist
- this.standardXHRResponse(this.requests.shift());
+ assert.strictEqual(this.requests.length, 1, 'made a sidx request');
 
  const oldMaster = parseMasterXml({
  masterXml: loader.masterXml_,
@@ -1691,7 +1707,7 @@ QUnit.test('refreshXml_: requests the sidx if it changed', function(assert) {
  );
  loader.refreshXml_();
 
- assert.strictEqual(this.requests.length, 1, 'manifest is being requested');
+ assert.strictEqual(this.requests.length, 2, 'manifest is being requested');
  newMaster = parseMasterXml({
  masterXml: loader.masterXml_,
  srcUrl: loader.srcUrl,
@@ -1771,7 +1787,9 @@ QUnit.test('refreshXml_: updates playlists if segment uri changed, but media seq
  );
 });
 
-QUnit.test('refreshXml_: updates playlists if sidx changed', function(assert) {
+// As of this writing, live SIDX where the SIDX value changes is not supported
+// Also note that the test uses a VOD SIDX playlist that is refreshed with a live one
+QUnit.skip('refreshXml_: updates playlists if sidx changed', function(assert) {
  const loader = new DashPlaylistLoader('dash-sidx.mpd', this.fakeVhs);
 
  loader.load();
@@ -2247,6 +2265,8 @@ QUnit.test('child playlist moves to HAVE_METADATA when initialized with a live m
 });
 
 QUnit.test('returns to HAVE_METADATA after refreshing the playlist', function(assert) {
+ // start at 4 seconds past epoch for 2x 2 second segments
+ this.clock.tick(4 * 1000);
  const loader = new DashPlaylistLoader('dash-live.mpd', this.fakeVhs);
 
  loader.load();
@@ -2255,8 +2275,8 @@ QUnit.test('returns to HAVE_METADATA after refreshing the playlist', function(as
  loader.media(loader.master.playlists[0]);
  this.clock.tick(1);
 
- // 10s, one target duration
- this.clock.tick(10 * 1000);
+ // 2s, one segment duration
+ this.clock.tick(2 * 1000);
  assert.strictEqual(loader.state, 'HAVE_METADATA', 'the state is correct');
 });
 
@@ -2483,6 +2503,8 @@ QUnit.test('use MPD.Location when refreshing the xml', function(assert) {
 });
 
 QUnit.test('refreshes the xml if there is a minimumUpdatePeriod', function(assert) {
+ // start at 4 seconds past epoch for 2x 2 second segments
+ this.clock.tick(4 * 1000);
  const loader = new DashPlaylistLoader('dash-live.mpd', this.fakeVhs);
  let minimumUpdatePeriods = 0;
 
@@ -2502,6 +2524,8 @@ QUnit.test('refreshes the xml if there is a minimumUpdatePeriod', function(asser
 });
 
 QUnit.test('stop xml refresh if minimumUpdatePeriod is removed', function(assert) {
+ // start at 4 seconds past epoch for 2x 2 second segments
+ this.clock.tick(4 * 1000);
  const loader = new DashPlaylistLoader('dash-live.mpd', this.fakeVhs);
  let minimumUpdatePeriods = 0;
 
@@ -2529,6 +2553,8 @@ QUnit.test('stop xml refresh if minimumUpdatePeriod is removed', function(assert
 });
 
 QUnit.test('continue xml refresh every targetDuration if minimumUpdatePeriod is 0', function(assert) {
+ // start at 4 seconds past epoch for 2x 2 second segments
+ this.clock.tick(4 * 1000);
  const loader = new DashPlaylistLoader('dash-live.mpd', this.fakeVhs);
  let minimumUpdatePeriods = 0;
 
@@ -2562,23 +2588,6 @@ QUnit.test('continue xml refresh every targetDuration if minimumUpdatePeriod is
  assert.equal(minimumUpdatePeriods, 2, '3rd minimumUpdatePeriod after targetDuration');
 });
 
-QUnit.test('media playlists "refresh" by re-parsing master xml', function(assert) {
- const loader = new DashPlaylistLoader('dash-live.mpd', this.fakeVhs);
- let refreshes = 0;
-
- loader.on('mediaupdatetimeout', () => refreshes++);
-
- loader.load();
- this.standardXHRResponse(this.requests.shift());
- loader.media(loader.master.playlists[0]);
- this.clock.tick(1);
-
- // 1s, half segment target duration, since the playlist didn't change
- this.clock.tick(2 * 500);
-
- assert.equal(refreshes, 1, 'refreshed playlist after last segment duration');
-});
-
 QUnit.test('delays load when on final rendition', function(assert) {
  const loader = new DashPlaylistLoader('dash.mpd', this.fakeVhs);
  const origHasPendingRequest = loader.hasPendingRequest;
@@ -2715,6 +2724,8 @@ QUnit.test('child loaders wait for async action before moving to HAVE_MASTER', f
 });
 
 QUnit.test('load resumes the media update timer for live playlists', function(assert) {
+ // start at 4 seconds past epoch for 2x 2 second segments
+ this.clock.tick(4 * 1000);
  const loader = new DashPlaylistLoader('dash-live.mpd', this.fakeVhs);
 
  loader.load();
@@ -2771,6 +2782,8 @@ QUnit.test('pause removes minimum update period timeout', function(assert) {
 });
 
 QUnit.test('load resumes minimum update period timeout for live', function(assert) {
+ // start at 4 seconds past epoch for 2x 2 second segments
+ this.clock.tick(4 * 1000);
  const loader = new DashPlaylistLoader('dash-live.mpd', this.fakeVhs);
 
  loader.load();
@@ -2820,3 +2833,43 @@ QUnit.test('pause does not remove minimum update period timeout when not master'
  'minimum update period timeout set'
  );
 });
+
+QUnit.test('updateMaster: merges in top level timelineStarts', function(assert) {
+ const prev = {
+ timelineStarts: [0, 1],
+ playlists: [{
+ uri: '0',
+ id: 0,
+ segments: [{
+ presentationTime: 0,
+ timeline: 0
+ }, {
+ presentationTime: 1,
+ timeline: 1
+ }]
+ }],
+ mediaGroups: {
+ AUDIO: {},
+ SUBTITLES: {}
+ }
+ };
+ const next = {
+ timelineStarts: [2],
+ playlists: [{
+ uri: '0',
+ id: 0,
+ segments: [{
+ presentationTime: 2,
+ timeline: 2
+ }]
+ }],
+ mediaGroups: {
+ AUDIO: {},
+ SUBTITLES: {}
+ }
+ };
+
+ const update = updateMaster(prev, next);
+
+ assert.deepEqual(update.timelineStarts, [2], 'updated timelineStarts');
+});

test/manifests/dash-live.mpd

@@ -1,5 +1,5 @@
 <?xml version="1.0"?>
-<MPD xmlns="urn:mpeg:dash:schema:mpd:2011" profiles="urn:mpeg:dash:profile:full:2011" minBufferTime="1.5" minimumUpdatePeriod="PT4S" type="dynamic" availabilityStartTime="1970-01-01T00:00:00Z" timeShiftBufferDepth="PT1H0M0S">
+<MPD xmlns="urn:mpeg:dash:schema:mpd:2011" profiles="urn:mpeg:dash:profile:isoff-live:2011" minBufferTime="1.5" minimumUpdatePeriod="PT4S" type="dynamic" availabilityStartTime="1970-01-01T00:00:00Z" timeShiftBufferDepth="PT1H0M0S">
  <Period start="PT0S">
  <BaseURL>main/</BaseURL>
  <AdaptationSet mimeType="video/mp4">