Add mdat support to the generator. Stub out media segment creation

Create a helper method to build mdat boxes. Generate an empty moof and a real mdat when a NAL unit is parsed.

 (function(window, videojs, undefined) {
 'use strict';
 
-var box, dinf, ftyp, minf, moof, moov, mvex, mvhd, trak, tkhd, mdia, mdhd, hdlr, stbl,
+var box, dinf, ftyp, mdat, minf, moof, moov, mvex, mvhd, trak, tkhd, mdia, mdhd, hdlr, stbl,
     stsd, styp, types, MAJOR_BRAND, MINOR_VERSION, VIDEO_HDLR, AUDIO_HDLR, HDLR_TYPES, VMHD, DREF, STCO, STSC, STSZ, STTS, TREX,
     Uint8Array, DataView;
 
@@ -19,6 +19,7 @@ DataView = window.DataView;
     dref: [],
     ftyp: [],
     hdlr: [],
+    mdat: [],
     mdhd: [],
     mdia: [],
     mfhd: [],
@@ -165,6 +166,9 @@ ftyp = function() {
 hdlr = function(type) {
   return box(types.hdlr, HDLR_TYPES[type]);
 };
+mdat = function(data) {
+  return box(types.mdat, data);
+};
 mdhd = function(duration) {
   return box(types.mdhd, new Uint8Array([
     0x00, // version 0
@@ -359,6 +363,7 @@ trak = function(duration, width, height, type) {
 
 window.videojs.mp4 = {
   ftyp: ftyp,
+  mdat: mdat,
   moof: moof,
   moov: moov,
   initSegment: function() {

@@ -440,10 +440,19 @@ Transmuxer = function() {
   this.initSegment = mp4.initSegment();
 
   aacStream.on('data', function(data) {
-    self.trigger('data', data);
   });
   h264Stream.on('data', function(data) {
-    self.trigger('data', data);
+    var
+      moof = mp4.moof([]),
+      mdat = mp4.mdat(data.data),
+      boxes = new Uint8Array(moof.byteLength + mdat.byteLength);
+
+    boxes.set(moof);
+    boxes.set(mdat, moof.byteLength);
+
+    self.trigger('data', {
+      data: boxes
+    });
   });
   // feed incoming data to the front of the parsing pipeline
   this.push = function(data) {

@@ -264,5 +264,15 @@ test('generates a minimal moof', function() {
   equal(moof[0].boxes[1].boxes[1].trackId, 2, 'wrote the second track id');
 });
 
+test('generates an mdat', function() {
+  var
+    data = mp4.mdat(new Uint8Array([1, 2, 3, 4])),
+    mdat = videojs.inspectMp4(data);
+
+  equal(mdat.length, 1, 'generated one box');
+  equal(mdat[0].type, 'mdat', 'generated an mdat box');
+  deepEqual(mdat[0].byteLength, 4, 'encapsulated the data');
+});
+
 
 })(window, window.videojs);

@@ -643,7 +643,7 @@ test('generates an init segment', function() {
 });
 
 test('parses an example mp2t file and generates media segments', function() {
-  var segments = [], i, segment;
+  var segments = [], i, boxes;
   transmuxer.on('data', function(segment) {
     segments.push(segment);
   });
@@ -653,9 +653,14 @@ test('parses an example mp2t file and generates media segments', function() {
   ok(segments.length, 'generated media segments');
   i = segments.length;
   while (i--) {
-    segment = videojs.inspectMp4(segments[i].data);
+    boxes = videojs.inspectMp4(segments[i].data);
+    equal(boxes.length, 2, 'segments are composed of two boxes');
+    equal(boxes[0].type, 'moof', 'first box is a moof');
+    equal(boxes[0].boxes.length, 2, 'moof has three children');
+    equal(boxes[0].boxes[0].type, 'mfhd', 'mfhd is a child of the moof');
+    equal(boxes[0].boxes[1].type, 'traf', 'traf is a child of the moof');
+    equal(boxes[1].type, 'mdat', 'second box is an mdat');
   }
-  console.log(segments);
 });
 
 })(window, window.videojs);