From 599ef68df80d00dd816f2ad41e8a68568c6cca94 Mon Sep 17 00:00:00 2001
From: Andrew Meadows <andrew@highfidelity.io>
Date: Fri, 20 Feb 2015 08:26:11 -0800
Subject: [PATCH] fix for scratchy audio on windows

---
 interface/src/audio/AudioScope.h           |  2 +-
 libraries/audio-client/src/AudioClient.cpp | 21 +++++++++------------
 libraries/audio-client/src/AudioClient.h   | 14 ++++++++++++--
 3 files changed, 22 insertions(+), 15 deletions(-)

diff --git a/interface/src/audio/AudioScope.h b/interface/src/audio/AudioScope.h
index df902fe7cd..cc9367e2d5 100644
--- a/interface/src/audio/AudioScope.h
+++ b/interface/src/audio/AudioScope.h
@@ -75,4 +75,4 @@ private:
 
 };
 
-#endif // hifi_AudioScope_h
\ No newline at end of file
+#endif // hifi_AudioScope_h
diff --git a/libraries/audio-client/src/AudioClient.cpp b/libraries/audio-client/src/AudioClient.cpp
index b427d5ba42..49dd1e1a35 100644
--- a/libraries/audio-client/src/AudioClient.cpp
+++ b/libraries/audio-client/src/AudioClient.cpp
@@ -85,16 +85,9 @@ AudioClient::AudioClient() :
     _isStereoInput(false),
     _outputStarveDetectionStartTimeMsec(0),
     _outputStarveDetectionCount(0),
-    _outputBufferSizeFrames("audioOutputBufferSize",
-                            DEFAULT_MAX_FRAMES_OVER_DESIRED),
-#ifdef Q_OS_ANDROID
-    _outputStarveDetectionEnabled("audioOutputStarveDetectionEnabled",
-                                  false),
-#else
+    _outputBufferSizeFrames("audioOutputBufferSize", DEFAULT_AUDIO_OUTPUT_BUFFER_SIZE_FRAMES),
     _outputStarveDetectionEnabled("audioOutputStarveDetectionEnabled",
                                   DEFAULT_AUDIO_OUTPUT_STARVE_DETECTION_ENABLED),
-#endif
-
     _outputStarveDetectionPeriodMsec("audioOutputStarveDetectionPeriod",
                                      DEFAULT_AUDIO_OUTPUT_STARVE_DETECTION_PERIOD),
     _outputStarveDetectionThreshold("audioOutputStarveDetectionThreshold",
@@ -1089,12 +1082,16 @@ void AudioClient::outputNotify() {
             } else {
                 _outputStarveDetectionCount += recentUnfulfilled;
                 if (_outputStarveDetectionCount > _outputStarveDetectionThreshold.get()) {
-                    int newOutputBufferSizeFrames = _outputBufferSizeFrames.get() + 1;
-                    qDebug() << "Starve detection threshold met, increasing buffer size to " << newOutputBufferSizeFrames;
-                    setOutputBufferSize(newOutputBufferSizeFrames);
-
                     _outputStarveDetectionStartTimeMsec = now;
                     _outputStarveDetectionCount = 0;
+
+                    int oldOutputBufferSizeFrames = _outputBufferSizeFrames.get();
+                    int newOutputBufferSizeFrames = oldOutputBufferSizeFrames + 1;
+                    setOutputBufferSize(newOutputBufferSizeFrames);
+                    newOutputBufferSizeFrames = _outputBufferSizeFrames.get();
+                    if (newOutputBufferSizeFrames > oldOutputBufferSizeFrames) {
+                        qDebug() << "Starve detection threshold met, increasing buffer size to " << newOutputBufferSizeFrames;
+                    }
                 }
             }
         }
diff --git a/libraries/audio-client/src/AudioClient.h b/libraries/audio-client/src/AudioClient.h
index 0095a885eb..811282c0a1 100644
--- a/libraries/audio-client/src/AudioClient.h
+++ b/libraries/audio-client/src/AudioClient.h
@@ -56,8 +56,18 @@ static const int NUM_AUDIO_CHANNELS = 2;
 
 static const int DEFAULT_AUDIO_OUTPUT_BUFFER_SIZE_FRAMES = 3;
 static const int MIN_AUDIO_OUTPUT_BUFFER_SIZE_FRAMES = 1;
-static const int MAX_AUDIO_OUTPUT_BUFFER_SIZE_FRAMES = 20;
-static const int DEFAULT_AUDIO_OUTPUT_STARVE_DETECTION_ENABLED = true;
+#ifdef _WIN32
+    // WORKAROUND: Some sound devices on Windows (at least 8.1) will get scratchy if their output 
+    // buffer is set too high so we have to limit the number of frames in the buffer.
+    static const int MAX_AUDIO_OUTPUT_BUFFER_SIZE_FRAMES = 5;
+#else
+    static const int MAX_AUDIO_OUTPUT_BUFFER_SIZE_FRAMES = 20;
+#endif
+#ifdef Q_OS_ANDROID
+    static const int DEFAULT_AUDIO_OUTPUT_STARVE_DETECTION_ENABLED = false;
+#else
+    static const int DEFAULT_AUDIO_OUTPUT_STARVE_DETECTION_ENABLED = true;
+#endif
 static const int DEFAULT_AUDIO_OUTPUT_STARVE_DETECTION_THRESHOLD = 3;
 static const quint64 DEFAULT_AUDIO_OUTPUT_STARVE_DETECTION_PERIOD = 10 * 1000; // 10 Seconds