Allow user to change DPLII decoding quality

Source/Core/AudioCommon/AudioCommon.cpp

@@ -101,6 +101,11 @@ std::string GetDefaultSoundBackend()
   return backend;
 }
 
+DPL2Quality GetDefaultDPL2Quality()
+{
+  return DPL2Quality::High;
+}
+
 std::vector<std::string> GetSoundBackends()
 {
   std::vector<std::string> backends;

Source/Core/AudioCommon/AudioCommon.h

@@ -9,6 +9,7 @@
 #include <string_view>
 #include <vector>
 
+#include "AudioCommon/Enums.h"
 #include "AudioCommon/SoundStream.h"
 
 class Mixer;
@@ -21,6 +22,7 @@ void InitSoundStream();
 void ShutdownSoundStream();
 std::string GetDefaultSoundBackend();
 std::vector<std::string> GetSoundBackends();
+DPL2Quality GetDefaultDPL2Quality();
 bool SupportsDPL2Decoder(std::string_view backend);
 bool SupportsLatencyControl(std::string_view backend);
 bool SupportsVolumeChanges(std::string_view backend);

Source/Core/AudioCommon/AudioCommon.vcxproj

@@ -53,6 +53,7 @@
     <ClInclude Include="AudioStretcher.h" />
     <ClInclude Include="CubebStream.h" />
     <ClInclude Include="CubebUtils.h" />
+    <ClInclude Include="Enums.h" />
     <ClInclude Include="Mixer.h" />
     <ClInclude Include="NullSoundStream.h" />
     <ClInclude Include="OpenALStream.h" />

Source/Core/AudioCommon/AudioCommon.vcxproj.filters

@@ -56,6 +56,7 @@
       <Filter>SoundStreams</Filter>
     </ClInclude>
     <ClInclude Include="SurroundDecoder.h" />
+    <ClInclude Include="Enums.h" />
   </ItemGroup>
   <ItemGroup>
     <Text Include="CMakeLists.txt" />

Source/Core/AudioCommon/CMakeLists.txt

@@ -7,6 +7,7 @@ add_library(audiocommon
   CubebStream.h
   CubebUtils.cpp
   CubebUtils.h
+  Enums.h
   Mixer.cpp
   Mixer.h
   SurroundDecoder.cpp

Source/Core/AudioCommon/Enums.h

@@ -0,0 +1,16 @@
+// Copyright 2019 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#pragma once
+
+namespace AudioCommon
+{
+enum class DPL2Quality
+{
+  Low = 0,
+  Medium = 1,
+  High = 2,
+  Highest = 3
+};
+}  // namespace AudioCommon

Source/Core/AudioCommon/Mixer.cpp

@@ -3,6 +3,7 @@
 // Refer to the license.txt file included.
 
 #include "AudioCommon/Mixer.h"
+#include "AudioCommon/Enums.h"
 
 #include <algorithm>
 #include <cmath>
@@ -12,11 +13,28 @@
 #include "Common/CommonTypes.h"
 #include "Common/Logging/Log.h"
 #include "Common/Swap.h"
+#include "Core/Config/MainSettings.h"
 #include "Core/ConfigManager.h"
 
+static u32 DPL2QualityToFrameBlockSize(AudioCommon::DPL2Quality quality)
+{
+  switch (quality)
+  {
+  case AudioCommon::DPL2Quality::Low:
+    return 512;
+  case AudioCommon::DPL2Quality::Medium:
+    return 1024;
+  case AudioCommon::DPL2Quality::Highest:
+    return 4096;
+  default:
+    return 2048;
+  }
+}
+
 Mixer::Mixer(unsigned int BackendSampleRate)
     : m_sampleRate(BackendSampleRate), m_stretcher(BackendSampleRate),
-      m_surround_decoder(BackendSampleRate, SURROUND_BLOCK_SIZE)
+      m_surround_decoder(BackendSampleRate,
+                         DPL2QualityToFrameBlockSize(Config::Get(Config::MAIN_DPL2_QUALITY)))
 {
   INFO_LOG(AUDIO_INTERFACE, "Mixer is initialized");
 }

Source/Core/AudioCommon/Mixer.h

@@ -54,7 +54,6 @@ private:
   static constexpr u32 CONTROL_AVG = 32;  // In freq_shift per FIFO size offset
 
   const unsigned int SURROUND_CHANNELS = 6;
-  const unsigned int SURROUND_BLOCK_SIZE = 512;
 
   class MixerFifo final
   {