Matthew Gregan - Bug 476813 - progress events shouldn't be fired while the network is stalled. r+ doublec sr+ roc

content/media/video/public/nsMediaDecoder.h

@@ -343,8 +343,9 @@ protected:
   PRIntervalTime mProgressTime;
 
   // Time that data was last read from the media resource. Used for
-  // computing if the download has stalled. A value of 0 indicates that
-  // a stall event has already fired and not to fire another one until
+  // computing if the download has stalled and to rate limit progress events
+  // when data is arriving slower than PROGRESS_MS. A value of 0 indicates
+  // that a stall event has already fired and not to fire another one until
   // more data is received. Read/Write from the main thread only.
   PRIntervalTime mDataTime;
 

content/media/video/src/nsMediaDecoder.cpp

@@ -154,24 +154,25 @@ void nsMediaDecoder::Progress(PRBool aTimer)
     return;
 
   PRIntervalTime now = PR_IntervalNow();
-  if (mProgressTime == 0 ||
-      PR_IntervalToMilliseconds(PR_IntervalNow() - mProgressTime) >= PROGRESS_MS) {
+
+  if (!aTimer) {
+    mDataTime = now;
+  }
+
+  PRUint32 progressDelta = PR_IntervalToMilliseconds(now - mProgressTime);
+  PRUint32 networkDelta = PR_IntervalToMilliseconds(now - mDataTime);
+
+  // If PROGRESS_MS has passed since the last progress event fired and more
+  // data has arrived since then, fire another progress event.
+  if (progressDelta >= PROGRESS_MS && networkDelta <= PROGRESS_MS) {
     mElement->DispatchAsyncProgressEvent(NS_LITERAL_STRING("progress"));
     mProgressTime = now;
   }
 
-  // The test for aTimer is to ensure that we dispatch 'stalled'
-  // only when we are not receiving data.
-  if (aTimer &&
-      mDataTime != 0 &&
-      PR_IntervalToMilliseconds(now - mDataTime) >= STALL_MS) {
+  if (mDataTime != 0 && networkDelta >= STALL_MS) {
     mElement->DispatchAsyncProgressEvent(NS_LITERAL_STRING("stalled"));
     mDataTime = 0;
   }
-
-  if (!aTimer) {
-    mDataTime = now;
-  }
 }
 
 nsresult nsMediaDecoder::StartProgress()