Fix program date time handling

package.json

@@ -91,8 +91,8 @@
   "dependencies": {
     "aes-decrypter": "1.0.3",
     "global": "^4.3.0",
-    "m3u8-parser": "2.1.0",
     "mpd-parser": "0.4.0",
+    "m3u8-parser": "4.2.0",
     "mux.js": "4.3.2",
     "url-toolkit": "^2.1.3",
     "video.js": "^6.2.0",

src/sync-controller.js

@@ -29,17 +29,38 @@ export const syncPointStrategies = [
   {
     name: 'ProgramDateTime',
     run: (syncController, playlist, duration, currentTimeline, currentTime) => {
-      if (syncController.datetimeToDisplayTime && playlist.dateTimeObject) {
-        let playlistTime = playlist.dateTimeObject.getTime() / 1000;
-        let playlistStart = playlistTime + syncController.datetimeToDisplayTime;
-        let syncPoint = {
-          time: playlistStart,
-          segmentIndex: 0
-        };
+      if (!syncController.datetimeToDisplayTime) {
+        return null;
+      }
 
-        return syncPoint;
+      let segments = playlist.segments || [];
+      let syncPoint = null;
+      let lastDistance = null;
+
+      currentTime = currentTime || 0;
+
+      for (let i = 0; i < segments.length; i++) {
+        let segment = segments[i];
+
+        if (segment.dateTimeObject) {
+          let segmentTime = segment.dateTimeObject.getTime() / 1000;
+          let segmentStart = segmentTime + syncController.datetimeToDisplayTime;
+          let distance = Math.abs(currentTime - segmentStart);
+
+          // Once the distance begins to increase, we have passed
+          // currentTime and can stop looking for better candidates
+          if (lastDistance !== null && lastDistance < distance) {
+            break;
+          }
+
+          lastDistance = distance;
+          syncPoint = {
+            time: segmentStart,
+            segmentIndex: i
+          };
+        }
       }
-      return null;
+      return syncPoint;
     }
   },
   // Stategy "Segment": We have a known time mapping for a timeline and a
@@ -336,8 +357,11 @@ export default class SyncController extends videojs.EventTarget {
    * @param {Playlist} playlist - The currently active playlist
    */
   setDateTimeMapping(playlist) {
-    if (!this.datetimeToDisplayTime && playlist.dateTimeObject) {
-      let playlistTimestamp = playlist.dateTimeObject.getTime() / 1000;
+    if (!this.datetimeToDisplayTime &&
+        playlist.segments &&
+        playlist.segments.length &&
+        playlist.segments[0].dateTimeObject) {
+      let playlistTimestamp = playlist.segments[0].dateTimeObject.getTime() / 1000;
 
       this.datetimeToDisplayTime = -playlistTimestamp;
     }

test/sync-controller.test.js

@@ -46,7 +46,7 @@ QUnit.test('returns correct sync point for ProgramDateTime strategy', function(a
 
   assert.equal(syncPoint, null, 'no syncpoint when datetimeToDisplayTime not set');
 
-  playlist.dateTimeObject = datetime;
+  playlist.segments[0].dateTimeObject = datetime;
 
   this.syncController.setDateTimeMapping(playlist);
 
@@ -56,7 +56,7 @@ QUnit.test('returns correct sync point for ProgramDateTime strategy', function(a
 
   assert.equal(syncPoint, null, 'no syncpoint when datetimeObject not set on playlist');
 
-  newPlaylist.dateTimeObject = new Date(2012, 11, 12, 12, 12, 22);
+  newPlaylist.segments[0].dateTimeObject = new Date(2012, 11, 12, 12, 12, 22);
 
   syncPoint = strategy.run(this.syncController, newPlaylist, duration, timeline);
 
@@ -66,6 +66,58 @@ QUnit.test('returns correct sync point for ProgramDateTime strategy', function(a
   }, 'syncpoint found for ProgramDateTime set');
 });
 
+QUnit.test('ProgramDateTime strategy finds nearest segment for sync', function(assert) {
+  let strategy = getStrategy('ProgramDateTime');
+  let playlist = playlistWithDuration(40);
+  let timeline = 0;
+  let duration = Infinity;
+  let syncPoint;
+
+  syncPoint = strategy.run(this.syncController, playlist, duration, timeline, 23);
+
+  assert.equal(syncPoint, null, 'no syncpoint when datetimeToDisplayTime not set');
+
+  playlist.segments.forEach((segment, index) => {
+    segment.dateTimeObject = new Date(2012, 11, 12, 12, 12, 12 + (index * 10));
+  });
+
+  this.syncController.setDateTimeMapping(playlist);
+
+  let newPlaylist = playlistWithDuration(40);
+
+  syncPoint = strategy.run(this.syncController, newPlaylist, duration, timeline);
+
+  assert.equal(syncPoint, null, 'no syncpoint when datetimeObject not set on playlist');
+
+  newPlaylist.segments.forEach((segment, index) => {
+    segment.dateTimeObject = new Date(2012, 11, 12, 12, 12, 22 + (index * 10));
+  });
+
+  syncPoint = strategy.run(this.syncController, newPlaylist, duration, timeline, 23);
+
+  assert.deepEqual(syncPoint, {
+    time: 20,
+    segmentIndex: 1
+  }, 'syncpoint found for ProgramDateTime set');
+});
+
+QUnit.test('Does not set date time mapping if date time info not on first segment',
+function(assert) {
+  let playlist = playlistWithDuration(40);
+
+  playlist.segments[1].dateTimeObject = new Date(2012, 11, 12, 12, 12, 12);
+
+  this.syncController.setDateTimeMapping(playlist);
+
+  assert.notOk(this.syncController.datetimeToDisplayTime, 'did not set datetime mapping');
+
+  playlist.segments[0].dateTimeObject = new Date(2012, 11, 12, 12, 12, 2);
+
+  this.syncController.setDateTimeMapping(playlist);
+
+  assert.ok(this.syncController.datetimeToDisplayTime, 'did set date time mapping');
+});
+
 QUnit.test('returns correct sync point for Segment strategy', function(assert) {
   let strategy = getStrategy('Segment');
   let playlist = {