Swapped FFDShow's DPL2 decoder by FreeSurround

Added class in AudioCommon for the surround decoder

Source/Core/AudioCommon/SurroundDecoder.h

@@ -0,0 +1,36 @@
+// Copyright 2017 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <array>
+#include <memory>
+
+#include "Common/CommonTypes.h"
+#include "Common/FixedSizeQueue.h"
+
+class DPL2FSDecoder;
+
+namespace AudioCommon
+{
+class SurroundDecoder
+{
+public:
+  explicit SurroundDecoder(u32 sample_rate, u32 frame_block_size);
+  ~SurroundDecoder();
+  size_t QueryFramesNeededForSurroundOutput(const size_t output_frames) const;
+  void PutFrames(const short* in, const size_t num_frames_in);
+  void ReceiveFrames(float* out, const size_t num_frames_out);
+  void Clear();
+
+private:
+  u32 m_sample_rate;
+  u32 m_frame_block_size;
+
+  std::unique_ptr<DPL2FSDecoder> m_fsdecoder;
+  std::array<float, 32768> m_float_conversion_buffer;
+  FixedSizeQueue<float, 32768> m_decoded_fifo;
+};
+
+}  // AudioCommon