fix: on flush if a pmt has not been emitted and we have one, emit it (#388)

Author: brandonocasey

lib/m2ts/m2ts.js

@@ -294,6 +294,7 @@ TransportParseStream.STREAM_TYPES  = {
 ElementaryStream = function() {
   var
     self = this,
+    segmentHadPmt = false,
     // PES packet fragments
     video = {
       data: [],
@@ -488,6 +489,8 @@ ElementaryStream = function() {
           });
         }
 
+        segmentHadPmt = true;
+
         self.trigger('data', event);
       }
     })[data.type]();
@@ -519,6 +522,42 @@ ElementaryStream = function() {
   };
 
   this.flush = function() {
+    // if on flush we haven't had a pmt emitted
+    // and we have a pmt to emit. emit the pmt
+    // so that we trigger a trackinfo downstream.
+    if (!segmentHadPmt && programMapTable) {
+      var
+        pmt = {
+          type: 'metadata',
+          tracks: []
+        };
+      // translate audio and video streams to tracks
+      if (programMapTable.video !== null) {
+        pmt.tracks.push({
+          timelineStartInfo: {
+            baseMediaDecodeTime: 0
+          },
+          id: +programMapTable.video,
+          codec: 'avc',
+          type: 'video'
+        });
+      }
+
+      if (programMapTable.audio !== null) {
+        pmt.tracks.push({
+          timelineStartInfo: {
+            baseMediaDecodeTime: 0
+          },
+          id: +programMapTable.audio,
+          codec: 'adts',
+          type: 'audio'
+        });
+      }
+
+      self.trigger('data', pmt);
+    }
+
+    segmentHadPmt = false;
     this.flushStreams_();
     this.trigger('done');
   };