fix typo

Co-authored-by: Adam Waldron <acwald@gmail.com>

README.md

@@ -57,6 +57,7 @@ var manifest = [
   '0.ts',
   '#EXTINF:6,',
   '1.ts',
+  '#EXT-X-PROGRAM-DATE-TIME:2019-02-14T02:14:00.106Z'
   '#EXTINF:6,',
   '2.ts',
   '#EXT-X-ENDLIST'
@@ -79,6 +80,7 @@ Manifest {
   allowCache: boolean,
   endList: boolean,
   mediaSequence: number,
+  dateRanges: [],
   discontinuitySequence: number,
   playlistType: string,
   custom: {},
@@ -106,8 +108,6 @@ Manifest {
     'CLOSED-CAPTIONS': {},
     SUBTITLES: {}
   },
-  dateTimeString: string,
-  dateTimeObject: Date,
   targetDuration: number,
   totalDuration: number,
   discontinuityStarts: [number],
@@ -118,6 +118,7 @@ Manifest {
         offset: number
       },
       duration: number,
+      programDateTime:  number,
       attributes: {},
       discontinuity: number,
       uri: string,

src/parse-stream.js

@@ -356,7 +356,6 @@ export default class ParseStream extends Stream {
         };
         if (match[1]) {
           event.dateTimeString = match[1];
-          event.dateTimeObject = new Date(match[1]);
         }
         this.trigger('data', event);
         return;

src/parser.js

@@ -97,6 +97,8 @@ export default class Parser extends Stream {
     this.parseStream = new ParseStream();
     this.lineStream.pipe(this.parseStream);
 
+    this.lastProgramDateTime = null;
+
     /* eslint-disable consistent-this */
     const self = this;
     /* eslint-enable consistent-this */
@@ -124,6 +126,7 @@ export default class Parser extends Stream {
     this.manifest = {
       allowCache: true,
       discontinuityStarts: [],
+      dateRanges: [],
       segments: []
     };
     // keep track of the last seen segment's byte range end, as segments are not required
@@ -451,17 +454,21 @@ export default class Parser extends Stream {
               this.manifest.discontinuityStarts.push(uris.length);
             },
             'program-date-time'() {
-              if (typeof this.manifest.dateTimeString === 'undefined') {
-                // PROGRAM-DATE-TIME is a media-segment tag, but for backwards
-                // compatibility, we add the first occurence of the PROGRAM-DATE-TIME tag
-                // to the manifest object
-                // TODO: Consider removing this in future major version
-                this.manifest.dateTimeString = entry.dateTimeString;
-                this.manifest.dateTimeObject = entry.dateTimeObject;
-              }
+              const { lastProgramDateTime } = this;
 
-              currentUri.dateTimeString = entry.dateTimeString;
-              currentUri.dateTimeObject = entry.dateTimeObject;
+              this.lastProgramDateTime = new Date(entry.dateTimeString).getTime();
+
+              // We should extrapolate Program Date Time backward only during first program date time occurrence.
+              // Once we have at least one program date time point, we can always extrapolate it forward using lastProgramDateTime reference.
+              if (lastProgramDateTime === null) {
+                // Extrapolate Program Date Time backward
+                // Since it is first program date time occurrence we're assuming that
+                // all this.manifest.segments have no program date time info
+                this.manifest.segments.reduceRight((programDateTime, segment) => {
+                  segment.programDateTime = programDateTime - (segment.duration * 1000);
+                  return segment.programDateTime;
+                }, this.lastProgramDateTime);
+              }
             },
             targetduration() {
               if (!isFinite(entry.duration) || entry.duration < 0) {
@@ -634,7 +641,6 @@ export default class Parser extends Stream {
               setHoldBack.call(this, this.manifest);
             },
             'daterange'() {
-              this.manifest.dateRanges = this.manifest.dateRanges || [];
               this.manifest.dateRanges.push(camelCaseKeys(entry.attributes));
               const index = this.manifest.dateRanges.length - 1;
 
@@ -678,11 +684,6 @@ export default class Parser extends Stream {
 
                 this.manifest.dateRanges[index].endDate = new Date(newDateInSeconds);
               }
-              if (dateRange && !this.manifest.dateTimeString) {
-                this.trigger('warn', {
-                  message: 'A playlist with EXT-X-DATERANGE tag must contain atleast one EXT-X-PROGRAM-DATE-TIME tag'
-                });
-              }
               if (!dateRangeTags[dateRange.id]) {
                 dateRangeTags[dateRange.id] = dateRange;
               } else {
@@ -725,6 +726,12 @@ export default class Parser extends Stream {
           // reset the last byterange end as it needs to be 0 between parts
           lastPartByterangeEnd = 0;
 
+          // Once we have at least one program date time we can always extrapolate it forward
+          if (this.lastProgramDateTime !== null) {
+            currentUri.programDateTime = this.lastProgramDateTime;
+            this.lastProgramDateTime += currentUri.duration * 1000;
+          }
+
           // prepare for the next URI
           currentUri = {};
         },
@@ -777,7 +784,13 @@ export default class Parser extends Stream {
   end() {
     // flush any buffered input
     this.lineStream.push('\n');
+    if (this.manifest.dateRanges.length && this.lastProgramDateTime === null) {
+      this.trigger('warn', {
+        message: 'A playlist with EXT-X-DATERANGE tag must contain atleast one EXT-X-PROGRAM-DATE-TIME tag'
+      });
+    }
 
+    this.lastProgramDateTime = null;
     this.trigger('end');
   }
   /**

test/fixtures/integration/absoluteUris.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 0,
   playlistType: 'VOD',
   segments: [

test/fixtures/integration/allowCache.js

@@ -1,6 +1,7 @@
 module.exports = {
   allowCache: true,
   mediaSequence: 0,
+  dateRanges: [],
   playlistType: 'VOD',
   segments: [
     {

test/fixtures/integration/allowCacheInvalid.js

@@ -1,6 +1,7 @@
 module.exports = {
   allowCache: true,
   mediaSequence: 0,
+  dateRanges: [],
   playlistType: 'VOD',
   segments: [
     {

test/fixtures/integration/alternateAudio.js

@@ -1,6 +1,7 @@
 module.exports = {
   allowCache: true,
   discontinuityStarts: [],
+  dateRanges: [],
   mediaGroups: {
     // TYPE
     'AUDIO': {

test/fixtures/integration/alternateVideo.js

@@ -1,6 +1,7 @@
 module.exports = {
   allowCache: true,
   discontinuityStarts: [],
+  dateRanges: [],
   mediaGroups: {
     'AUDIO': {
       aac: {

test/fixtures/integration/brightcove.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   playlists: [
     {
       attributes: {

test/fixtures/integration/byteRange.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 0,
   playlistType: 'VOD',
   segments: [

test/fixtures/integration/dateTime.js

@@ -1,18 +1,17 @@
 module.exports = {
   allowCache: false,
   mediaSequence: 0,
+  dateRanges: [],
   playlistType: 'VOD',
   segments: [
     {
-      dateTimeString: '2016-06-22T09:20:16.166-04:00',
-      dateTimeObject: new Date('2016-06-22T09:20:16.166-04:00'),
+      programDateTime: 1466601616166,
       duration: 10,
       timeline: 0,
       uri: 'hls_450k_video.ts'
     },
     {
-      dateTimeString: '2016-06-22T09:20:26.166-04:00',
-      dateTimeObject: new Date('2016-06-22T09:20:26.166-04:00'),
+      programDateTime: 1466601626166,
       duration: 10,
       timeline: 0,
       uri: 'hls_450k_video.ts'
@@ -20,8 +19,6 @@ module.exports = {
   ],
   targetDuration: 10,
   endList: true,
-  dateTimeString: '2016-06-22T09:20:16.166-04:00',
-  dateTimeObject: new Date('2016-06-22T09:20:16.166-04:00'),
   discontinuitySequence: 0,
   discontinuityStarts: []
 };

test/fixtures/integration/diff-init-key.js

@@ -2,6 +2,7 @@ module.exports = {
   allowCache: true,
   discontinuitySequence: 0,
   discontinuityStarts: [],
+  dateRanges: [],
   mediaSequence: 7794,
   segments: [
     {

test/fixtures/integration/disallowCache.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: false,
+  dateRanges: [],
   mediaSequence: 0,
   playlistType: 'VOD',
   segments: [

test/fixtures/integration/disc-sequence.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 0,
   discontinuitySequence: 3,
   segments: [

test/fixtures/integration/discontinuity.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 0,
   discontinuitySequence: 0,
   segments: [

test/fixtures/integration/domainUris.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 0,
   playlistType: 'VOD',
   segments: [

test/fixtures/integration/empty.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   discontinuityStarts: [],
   segments: []
 };

test/fixtures/integration/emptyAllowCache.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 0,
   playlistType: 'VOD',
   segments: [

test/fixtures/integration/emptyMediaSequence.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 0,
   playlistType: 'VOD',
   segments: [

test/fixtures/integration/emptyPlaylistType.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 0,
   segments: [
     {

test/fixtures/integration/emptyTargetDuration.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   playlists: [
     {
       attributes: {

test/fixtures/integration/encrypted.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 7794,
   discontinuitySequence: 0,
   discontinuityStarts: [],

test/fixtures/integration/event.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 0,
   playlistType: 'EVENT',
   segments: [

test/fixtures/integration/extXPlaylistTypeInvalidPlaylist.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 1,
   segments: [
     {

test/fixtures/integration/extinf.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 0,
   playlistType: 'VOD',
   segments: [

test/fixtures/integration/fmp4.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 1,
   playlistType: 'VOD',
   targetDuration: 6,

test/fixtures/integration/headerOnly.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   discontinuityStarts: [],
   segments: []
 };

test/fixtures/integration/invalidAllowCache.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 0,
   playlistType: 'VOD',
   segments: [

test/fixtures/integration/invalidMediaSequence.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 0,
   playlistType: 'VOD',
   segments: [

test/fixtures/integration/invalidPlaylistType.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 0,
   segments: [
     {

test/fixtures/integration/invalidTargetDuration.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 0,
   playlistType: 'VOD',
   segments: [

test/fixtures/integration/liveMissingSegmentDuration.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 0,
   playlistType: 'VOD',
   segments: [

test/fixtures/integration/liveStart30sBefore.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 0,
   segments: [
     {

test/fixtures/integration/llhls-byte-range.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   discontinuitySequence: 0,
   discontinuityStarts: [],
   mediaSequence: 0,

test/fixtures/integration/llhls-delta-byte-range.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   discontinuitySequence: 0,
   discontinuityStarts: [],
   mediaSequence: 0,

test/fixtures/integration/llhls.js

@@ -1,7 +1,6 @@
 module.exports = {
   allowCache: true,
-  dateTimeObject: new Date('2019-02-14T02:13:36.106Z'),
-  dateTimeString: '2019-02-14T02:13:36.106Z',
+  dateRanges: [],
   discontinuitySequence: 0,
   discontinuityStarts: [],
   mediaSequence: 266,
@@ -38,8 +37,7 @@ module.exports = {
   partTargetDuration: 0.33334,
   segments: [
     {
-      dateTimeObject: new Date('2019-02-14T02:13:36.106Z'),
-      dateTimeString: '2019-02-14T02:13:36.106Z',
+      programDateTime: 1550110416106,
       duration: 4.00008,
       map: {
         uri: 'init.mp4'
@@ -52,6 +50,7 @@ module.exports = {
       map: {
         uri: 'init.mp4'
       },
+      programDateTime: 1550110420106.08,
       timeline: 0,
       uri: 'fileSequence267.mp4'
     },
@@ -60,6 +59,7 @@ module.exports = {
       map: {
         uri: 'init.mp4'
       },
+      programDateTime: 1550110424106.1602,
       timeline: 0,
       uri: 'fileSequence268.mp4'
     },
@@ -68,6 +68,7 @@ module.exports = {
       map: {
         uri: 'init.mp4'
       },
+      programDateTime: 1550110428106.2402,
       timeline: 0,
       uri: 'fileSequence269.mp4'
     },
@@ -76,6 +77,7 @@ module.exports = {
       map: {
         uri: 'init.mp4'
       },
+      programDateTime: 1550110432106.3203,
       timeline: 0,
       uri: 'fileSequence270.mp4'
     },
@@ -84,6 +86,7 @@ module.exports = {
       map: {
         uri: 'init.mp4'
       },
+      programDateTime: 1550110436106.4004,
       timeline: 0,
       uri: 'fileSequence271.mp4',
       parts: [
@@ -140,12 +143,11 @@ module.exports = {
       ]
     },
     {
-      dateTimeObject: new Date('2019-02-14T02:14:00.106Z'),
-      dateTimeString: '2019-02-14T02:14:00.106Z',
       duration: 4.00008,
       map: {
         uri: 'init.mp4'
       },
+      programDateTime: 1550110440106,
       timeline: 0,
       uri: 'fileSequence272.mp4',
       parts: [

test/fixtures/integration/llhlsDelta.js

@@ -1,7 +1,6 @@
 module.exports = {
   allowCache: true,
-  dateTimeObject: new Date('2019-02-14T02:14:00.106Z'),
-  dateTimeString: '2019-02-14T02:14:00.106Z',
+  dateRanges: [],
   discontinuitySequence: 0,
   discontinuityStarts: [],
   mediaSequence: 266,
@@ -42,16 +41,19 @@ module.exports = {
   segments: [
     {
       duration: 4.00008,
+      programDateTime: 1550110428105.7598,
       timeline: 0,
       uri: 'fileSequence269.mp4'
     },
     {
       duration: 4.00008,
+      programDateTime: 1550110432105.8398,
       timeline: 0,
       uri: 'fileSequence270.mp4'
     },
     {
       duration: 4.00008,
+      programDateTime: 1550110436105.92,
       timeline: 0,
       uri: 'fileSequence271.mp4',
       parts: [
@@ -108,9 +110,8 @@ module.exports = {
       ]
     },
     {
-      dateTimeObject: new Date('2019-02-14T02:14:00.106Z'),
-      dateTimeString: '2019-02-14T02:14:00.106Z',
       duration: 4.00008,
+      programDateTime: 1550110440106,
       timeline: 0,
       uri: 'fileSequence272.mp4',
       parts: [

test/fixtures/integration/manifestExtTTargetdurationNegative.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 0,
   segments: [
     {

test/fixtures/integration/manifestExtXEndlistEarly.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 0,
   segments: [
     {

test/fixtures/integration/manifestNoExtM3u.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 0,
   segments: [
     {

test/fixtures/integration/master-fmp4.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   discontinuityStarts: [],
   mediaGroups: {
     'AUDIO': {

test/fixtures/integration/master.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   playlists: [
     {
       attributes: {

test/fixtures/integration/media.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 0,
   playlistType: 'VOD',
   segments: [

test/fixtures/integration/mediaSequence.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 0,
   playlistType: 'VOD',
   segments: [

test/fixtures/integration/missingEndlist.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 0,
   segments: [
     {

test/fixtures/integration/missingExtinf.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 0,
   playlistType: 'VOD',
   segments: [

test/fixtures/integration/missingMediaSequence.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 0,
   playlistType: 'VOD',
   segments: [

test/fixtures/integration/missingSegmentDuration.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 0,
   playlistType: 'VOD',
   segments: [

test/fixtures/integration/multipleAudioGroups.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   discontinuityStarts: [],
   mediaGroups: {
     'AUDIO': {

test/fixtures/integration/multipleAudioGroupsCombinedMain.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   discontinuityStarts: [],
   mediaGroups: {
     'AUDIO': {

test/fixtures/integration/multipleTargetDurations.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 0,
   targetDuration: 10,
   segments: [

test/fixtures/integration/multipleVideo.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   discontinuityStarts: [],
   mediaGroups: {
     'AUDIO': {

test/fixtures/integration/negativeMediaSequence.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: -11,
   playlistType: 'VOD',
   segments: [

test/fixtures/integration/playlist.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 0,
   playlistType: 'VOD',
   segments: [

test/fixtures/integration/playlistMediaSequenceHigher.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 17,
   playlistType: 'VOD',
   segments: [

test/fixtures/integration/start.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 0,
   playlistType: 'VOD',
   segments: [

test/fixtures/integration/streamInfInvalid.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   playlists: [
     {
       attributes: {

test/fixtures/integration/twoMediaSequences.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 11,
   playlistType: 'VOD',
   segments: [

test/fixtures/integration/versionInvalid.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 0,
   playlistType: 'VOD',
   segments: [

test/fixtures/integration/whiteSpace.js

@@ -1,5 +1,6 @@
 module.exports = {
   allowCache: true,
+  dateRanges: [],
   mediaSequence: 0,
   playlistType: 'VOD',
   segments: [

test/fixtures/integration/zeroDuration.js

@@ -1,6 +1,7 @@
 module.exports = {
   allowCache: true,
   mediaSequence: 0,
+  dateRanges: [],
   playlistType: 'VOD',
   segments: [
     {

test/parse-stream.test.js

@@ -635,10 +635,6 @@ QUnit.test(
       element.dateTimeString, '2016-06-22T09:20:16.166-04:00',
       'dateTimeString is parsed'
     );
-    assert.deepEqual(
-      element.dateTimeObject, new Date('2016-06-22T09:20:16.166-04:00'),
-      'dateTimeObject is parsed'
-    );
 
     manifest = '#EXT-X-PROGRAM-DATE-TIME:2016-06-22T09:20:16.16389Z\n';
     this.lineStream.push(manifest);
@@ -650,10 +646,6 @@ QUnit.test(
       element.dateTimeString, '2016-06-22T09:20:16.16389Z',
       'dateTimeString is parsed'
     );
-    assert.deepEqual(
-      element.dateTimeObject, new Date('2016-06-22T09:20:16.16389Z'),
-      'dateTimeObject is parsed'
-    );
   }
 );
 QUnit.test('parses #EXT-X-STREAM-INF with common attributes', function(assert) {

test/parser.test.js

@@ -845,6 +845,71 @@ QUnit.module('m3u8s', function(hooks) {
     );
   });
 
+  QUnit.test('PDT value is assigned to segments with explicit #EXT-X-PROGRAM-DATE-TIME tags', function(assert) {
+    this.parser.push([
+      '#EXTM3U',
+      '#EXT-X-VERSION:6',
+      '#EXT-X-TARGETDURATION:8',
+      '#EXT-X-MEDIA-SEQUENCE:0',
+      '#EXTINF:8.0',
+      '#EXT-X-PROGRAM-DATE-TIME:2017-07-31T20:35:35.053+00:00',
+      'https://example.com/playlist1.m3u8',
+      '#EXTINF:8.0,',
+      '#EXT-X-PROGRAM-DATE-TIME:2017-07-31T22:14:10.053+00:00',
+      'https://example.com/playlist2.m3u8',
+      '#EXT-X-ENDLIST'
+    ].join('\n'));
+    this.parser.end();
+    assert.equal(this.parser.manifest.segments[0].programDateTime, new Date('2017-07-31T20:35:35.053+00:00').getTime());
+    assert.equal(this.parser.manifest.segments[1].programDateTime, new Date('2017-07-31T22:14:10.053+00:00').getTime());
+  });
+
+  QUnit.test('backfill PDT values when the first EXT-X-PROGRAM-DATE-TIME tag appears after one or more Media Segment URIs', function(assert) {
+    this.parser.push([
+      '#EXTM3U',
+      '#EXT-X-VERSION:6',
+      '#EXT-X-TARGETDURATION:8',
+      '#EXT-X-MEDIA-SEQUENCE:0',
+      '#EXTINF:8.0',
+      'https://example.com/playlist1.m3u8',
+      '#EXTINF:8.0,',
+      'https://example.com/playlist2.m3u8',
+      '#EXTINF:8.0',
+      '#EXT-X-PROGRAM-DATE-TIME:2017-07-31T20:35:35.053+00:00',
+      'https://example.com/playlist3.m3u8',
+      '#EXT-X-ENDLIST'
+    ].join('\n'));
+    this.parser.end();
+    const segments = this.parser.manifest.segments;
+
+    assert.equal(segments[2].programDateTime, new Date('2017-07-31T20:35:35.053+00:00').getTime());
+    assert.equal(segments[1].programDateTime, segments[2].programDateTime - (segments[1].duration * 1000));
+    assert.equal(segments[0].programDateTime, segments[1].programDateTime - (segments[0].duration * 1000));
+  });
+
+  QUnit.test('extrapolates forward when subsequent fragments do not have explicit PDT tags', function(assert) {
+    this.parser.push([
+      '#EXTM3U',
+      '#EXT-X-VERSION:6',
+      '#EXT-X-TARGETDURATION:8',
+      '#EXT-X-MEDIA-SEQUENCE:0',
+      '#EXTINF:8.0',
+      '#EXT-X-PROGRAM-DATE-TIME:2017-07-31T20:35:35.053+00:00',
+      'https://example.com/playlist1.m3u8',
+      '#EXTINF:8.0,',
+      'https://example.com/playlist2.m3u8',
+      '#EXTINF:8.0',
+      'https://example.com/playlist3.m3u8',
+      '#EXT-X-ENDLIST'
+    ].join('\n'));
+    this.parser.end();
+    const segments = this.parser.manifest.segments;
+
+    assert.equal(segments[0].programDateTime, new Date('2017-07-31T20:35:35.053+00:00').getTime());
+    assert.equal(segments[1].programDateTime, segments[0].programDateTime + segments[1].duration * 1000);
+    assert.equal(segments[2].programDateTime, segments[1].programDateTime + segments[2].duration * 1000);
+  });
+
   QUnit.test('warns when #EXT-X-DATERANGE missing attribute', function(assert) {
     this.parser.push([
       '#EXT-X-VERSION:3',