Merge pull request #1014 from unknownbrackets/ios

iOS: fix significant audio stutter

Core/HLE/__sceAudio.cpp

@@ -273,5 +273,5 @@ int __AudioMix(short *outstereo, int numFrames)
 		// DEBUG_LOG(HLE, "No underrun, mixed %i samples fine", numFrames);
 	}
 	section.unlock();
-	return numFrames;
+	return underrun >= 0 ? underrun : numFrames;
 }

Windows/DSoundStream.cpp

@@ -133,7 +133,8 @@ namespace DSound
 			{
 				int numBytesRendered = 4 * (*callback)(realtimeBuffer,numBytesToRender>>2,16,44100,2);
 
-				writeDataToBuffer(lastPos,(char *)realtimeBuffer,numBytesRendered);
+				if (numBytesRendered != 0)
+					writeDataToBuffer(lastPos,(char *)realtimeBuffer,numBytesRendered);
 
 				currentPos = ModBufferSize(lastPos + numBytesRendered);
 				totalRenderedBytes += numBytesRendered;