Add tfdt to track fragment boxes

According to the byte stream format registry, a media segment should contain at least one track fragment decode timestamp box.

@@ -37,6 +37,7 @@ DataView = window.DataView;
     stsz: [],
     stts: [],
     styp: [],
+    tfdt: [],
     tfhd: [],
     traf: [],
     trak: [],
@@ -406,7 +407,12 @@ traf = function(track) {
                (track.id & 0xFF000000) >> 24,
                (track.id & 0xFF0000) >> 16,
                (track.id & 0xFF00) >> 8,
-               (track.id & 0xFF),
+               (track.id & 0xFF) // track_ID
+             ])),
+             box(types.tfdt, new Uint8Array([
+               0x00, // version 0
+               0x00, 0x00, 0x00, // flags
+               0x00, 0x00, 0x00, 0x00 // baseMediaDecodeTime
              ])),
              trun(track));
 };
@@ -445,11 +451,12 @@ trun = function(track) {
 
   bytes = [
     0x00, // version 0
-    0x00, 0x0f, 0x00, // flags
+    0x00, 0x0f, 0x01, // flags
     (samples.length & 0xFF000000) >>> 24,
     (samples.length & 0xFF0000) >>> 16,
     (samples.length & 0xFF00) >>> 8,
-    samples.length & 0xFF // sample_count
+    samples.length & 0xFF, // sample_count
+    0x00, 0x00, 0x00, 0x00 // data_offset
   ];
 
   for (i = 0; i < samples.length; i++) {

@@ -339,12 +339,19 @@ test('generates a minimal moof', function() {
   equal(moof[0].boxes[0].type, 'mfhd', 'generated an mfhd box');
   equal(moof[0].boxes[0].sequenceNumber, 7, 'included the sequence_number');
   equal(moof[0].boxes[1].type, 'traf', 'generated a traf box');
-  equal(moof[0].boxes[1].boxes.length, 2, 'generated track fragment info');
+  equal(moof[0].boxes[1].boxes.length, 3, 'generated track fragment info');
   equal(moof[0].boxes[1].boxes[0].type, 'tfhd', 'generated a tfhd box');
   equal(moof[0].boxes[1].boxes[0].trackId, 17, 'wrote the first track id');
-  equal(moof[0].boxes[1].boxes[0].type, 'tfhd', 'generated a tfhd box');
-  trun = moof[0].boxes[1].boxes[1];
+  equal(moof[0].boxes[1].boxes[0].baseDataOffset, undefined, 'did not set a base data offset');
+
+  equal(moof[0].boxes[1].boxes[1].type, 'tfdt', 'generated a tfdt box');
+  ok(moof[0].boxes[1].boxes[1].baseMediaDecodeTime >= 0,
+     'media decode time is non-negative');
+
+  trun = moof[0].boxes[1].boxes[2];
   equal(trun.type, 'trun', 'generated a trun box');
+  equal(typeof trun.dataOffset, 'number', 'has a data offset');
+  ok(trun.dataOffset >= 0, 'has a non-negative data offset');
   equal(trun.samples.length, 2, 'wrote two samples');
 
   equal(trun.samples[0].duration, 9000, 'wrote a sample duration');
@@ -381,7 +388,7 @@ test('can generate a traf without samples', function() {
     }]),
     moof = videojs.inspectMp4(data);
 
-  equal(moof[0].boxes[1].boxes[1].samples.length, 0, 'generated no samples');
+  equal(moof[0].boxes[1].boxes[2].samples.length, 0, 'generated no samples');
 });
 
 test('generates an mdat', function() {

@@ -671,7 +671,7 @@ test('can parse a moof', function() {
                   type: 'tfhd',
                   version: 0,
                   size: 40,
-                  flags: new Uint8Array([0, 0, 0x3b]),
+                  flags: new Uint8Array([0x00, 0, 0x3b]),
                   trackId: 1,
                   baseDataOffset: 1,
                   sampleDescriptionIndex: 2,

@@ -880,7 +880,13 @@ validateTrackFragment = function(track, metadata) {
   equal(tfhd.type, 'tfhd', 'wrote a track fragment header');
   equal(tfhd.trackId, metadata.trackId, 'wrote the track id');
 
-  trun = track.boxes[1];
+  equal(track.boxes[1].type,
+        'tfdt',
+        'wrote a track fragment decode time box');
+  ok(track.boxes[1].baseMediaDecodeTime >= 0, 'base decode time is valid');
+
+  trun = track.boxes[2];
+  ok(trun.dataOffset >= 0, 'set data offset');
   ok(trun.samples.length > 0, 'generated media samples');
   for (i = 0; i < trun.samples.length; i++) {
     sample = trun.samples[i];