Merge pull request #171 from videojs/hotfix/more-audio-meta

Write out audio metadata frequently. Fixes #169.

@@ -23,6 +23,7 @@ window.videojs.Hls.AacStream = function() {
     pts_offset, // :int
     state, // :uint
     pes_length, // :int
+    lastMetaPts,
 
     adtsProtectionAbsent, // :Boolean
     adtsObjectType, // :int
@@ -43,6 +44,11 @@ window.videojs.Hls.AacStream = function() {
     // on the first invocation, capture the starting PTS value
     pts_offset = pts;
 
+    // keep track of the last time a metadata tag was written out
+    // set the initial value so metadata will be generated before any
+    // payload data
+    lastMetaPts = pts - 1000;
+
     // on subsequent invocations, calculate the PTS based on the starting offset
     this.setNextTimeStamp = function(pts, pes_size, dataAligned) {
       next_pts = pts - pts_offset;
@@ -157,7 +163,11 @@ window.videojs.Hls.AacStream = function() {
         newExtraData = (adtsObjectType << 11) |
                        (adtsSampleingIndex << 7) |
                        (adtsChanelConfig << 3);
-        if (newExtraData !== extraData) {
+
+        // write out metadata tags every 1 second so that the decoder
+        // is re-initialized quickly after seeking into a different
+        // audio configuration
+        if (newExtraData !== extraData || next_pts - lastMetaPts >= 1000) {
           aacFrame = new FlvTag(FlvTag.METADATA_TAG);
           aacFrame.pts = next_pts;
           aacFrame.dts = next_pts;
@@ -173,16 +183,19 @@ window.videojs.Hls.AacStream = function() {
 
           extraData = newExtraData;
           aacFrame = new FlvTag(FlvTag.AUDIO_TAG, true);
-          aacFrame.pts = aacFrame.dts;
           // For audio, DTS is always the same as PTS. We want to set the DTS
           // however so we can compare with video DTS to determine approximate
           // packet order
           aacFrame.pts = next_pts;
+          aacFrame.dts = aacFrame.pts;
+
           aacFrame.view.setUint16(aacFrame.position, newExtraData);
           aacFrame.position += 2;
           aacFrame.length = Math.max(aacFrame.length, aacFrame.position);
 
           this.tags.push(aacFrame);
+
+          lastMetaPts = next_pts;
         }
 
         // Skip the checksum if there is one

@@ -341,14 +341,22 @@
       currentPts = tag.pts;
 
       // generic flv headers
-      ok(type === 8 || type === 9 || type === 18,
-         'the type field specifies audio, video or script');
+      switch (type) {
+        case 8: ok(true, 'the type is audio');
+        break;
+        case 9: ok(true, 'the type is video');
+        break;
+        case 18: ok(true, 'the type is script');
+        break;
+        default: ok(false, 'the type (' + type + ') is unrecognized');
+      }
 
       byte = (tag.view.getUint32(1) & 0xFFFFFF00) >>> 8;
       equal(tag.bytes.byteLength - 11 - 4, byte, 'the size field is correct');
 
       byte = tag.view.getUint32(5) & 0xFFFFFF00;
-      ok(byte >= lastTime, 'the timestamp for the tag is greater than zero');
+      ok(byte >= lastTime,
+         'timestamp is increasing. last pts: ' + lastTime + ' this pts: ' + byte);
       lastTime = byte;
 
       // tag type-specific headers