Bug 1038091 - Pause the player instead of stopping it to avoid resetting playback position and resulting in audio clock going backward. r=kinetik

content/media/AudioStream.cpp

@@ -141,6 +141,7 @@ AudioStream::AudioStream()
   , mNeedsStart(false)
   , mShouldDropFrames(false)
   , mPendingAudioInitTask(false)
+  , mLastGoodPosition(0)
 {
   // keep a ref in case we shut down later than nsLayoutStatics
   mLatencyLog = AsyncLatencyLogger::Get(true);
@@ -856,7 +857,12 @@ AudioStream::GetPositionInFramesUnlocked()
     }
   }
 
-  return std::min<uint64_t>(position, INT64_MAX);
+  MOZ_ASSERT(position >= mLastGoodPosition, "cubeb position shouldn't go backward");
+  // This error handling/recovery keeps us in good shape in release build.
+  if (position >= mLastGoodPosition) {
+    mLastGoodPosition = position;
+  }
+  return std::min<uint64_t>(mLastGoodPosition, INT64_MAX);
 }
 
 int64_t

content/media/AudioStream.h

@@ -402,6 +402,9 @@ private:
   // True if there is a pending AudioInitTask. Shutdown() will wait until the
   // pending AudioInitTask is finished.
   bool mPendingAudioInitTask;
+  // The last good position returned by cubeb_stream_get_position(). Used to
+  // check if the cubeb position is going backward.
+  uint64_t mLastGoodPosition;
 };
 
 class AudioInitTask : public nsRunnable

media/libcubeb/src/cubeb_opensl.c

@@ -83,7 +83,7 @@ play_callback(SLPlayItf caller, void * user_ptr, SLuint32 event)
       assert(stm->draining);
       pthread_mutex_unlock(&stm->mutex);
       stm->state_callback(stm, stm->user_ptr, CUBEB_STATE_DRAINED);
-      (*stm->play)->SetPlayState(stm->play, SL_PLAYSTATE_STOPPED);
+      (*stm->play)->SetPlayState(stm->play, SL_PLAYSTATE_PAUSED);
       break;
     default:
       break;
@@ -116,7 +116,7 @@ bufferqueue_callback(SLBufferQueueItf caller, void * user_ptr)
       written = cubeb_resampler_fill(stm->resampler, buf,
                                         stm->queuebuf_len / stm->framesize);
       if (written < 0 || written * stm->framesize > stm->queuebuf_len) {
-        (*stm->play)->SetPlayState(stm->play, SL_PLAYSTATE_STOPPED);
+        (*stm->play)->SetPlayState(stm->play, SL_PLAYSTATE_PAUSED);
         return;
       }
     }