Bug 693095 - Fix audio stream position estimation for remoted streams. Also resurrect audio thread wait removed in bug 669556 when using remoted audio streams. r=cpearce

content/media/nsBuiltinDecoderStateMachine.cpp

@@ -635,6 +635,29 @@ void nsBuiltinDecoderStateMachine::AudioLoop()
         NS_WARNING("Int overflow calculating audio end time");
         break;
       }
+
+// The remoted audio stream does not block writes when the other end's buffers
+// are full, so this sleep is necessary to stop the audio thread spinning its
+// wheels.  When bug 695612 is fixed, this block of code can be removed.
+#if defined(REMOTE_AUDIO)
+      PRInt64 audioAhead = mAudioEndTime - GetMediaTime();
+      if (audioAhead > AMPLE_AUDIO_USECS &&
+          framesWritten > minWriteFrames)
+      {
+        // We've pushed enough audio onto the hardware that we've queued up a
+        // significant amount ahead of the playback position. The decode
+        // thread will be going to sleep, so we won't get any new audio
+        // anyway, so sleep until we need to push to the hardware again.
+        Wait(AMPLE_AUDIO_USECS / 2);
+        // Kick the decode thread; since above we only do a NotifyAll when
+        // we pop an audio chunk of the queue, the decoder won't wake up if
+        // we've got no more decoded chunks to push to the hardware. We can
+        // hit this condition if the last frame in the stream doesn't have
+        // it's EOS flag set, and the decode thread sleeps just after decoding
+        // that packet, but before realising there's no more packets.
+        mon.NotifyAll();
+      }
+#endif
     }
   }
   if (mReader->mAudioQueue.AtEndOfStream() &&