Swapped FFDShow's DPL2 decoder by FreeSurround

Added class in AudioCommon for the surround decoder

Source/Core/AudioCommon/SurroundDecoder.cpp

@@ -0,0 +1,93 @@
+// Copyright 2017 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#include <FreeSurround/FreeSurroundDecoder.h>
+#include <limits>
+
+#include "AudioCommon/SurroundDecoder.h"
+
+namespace AudioCommon
+{
+constexpr size_t STEREO_CHANNELS = 2;
+constexpr size_t SURROUND_CHANNELS = 6;
+
+SurroundDecoder::SurroundDecoder(u32 sample_rate, u32 frame_block_size)
+    : m_sample_rate(sample_rate), m_frame_block_size(frame_block_size)
+{
+  m_fsdecoder = std::make_unique<DPL2FSDecoder>();
+  m_fsdecoder->Init(cs_5point1, m_frame_block_size, m_sample_rate);
+}
+
+SurroundDecoder::~SurroundDecoder() = default;
+
+void SurroundDecoder::Clear()
+{
+  m_fsdecoder->flush();
+  m_decoded_fifo.clear();
+}
+
+// Currently only 6 channels are supported.
+size_t SurroundDecoder::QueryFramesNeededForSurroundOutput(const size_t output_frames) const
+{
+  if (m_decoded_fifo.size() < output_frames * SURROUND_CHANNELS)
+  {
+    // Output stereo frames needed to have at least the desired number of surround frames
+    size_t frames_needed = output_frames - m_decoded_fifo.size() / SURROUND_CHANNELS;
+    return frames_needed + m_frame_block_size - frames_needed % m_frame_block_size;
+  }
+
+  return 0;
+}
+
+// Receive and decode samples
+void SurroundDecoder::PutFrames(const short* in, const size_t num_frames_in)
+{
+  // Maybe check if it is really power-of-2?
+  s64 remaining_frames = static_cast<s64>(num_frames_in);
+  size_t frame_index = 0;
+
+  while (remaining_frames > 0)
+  {
+    // Convert to float
+    for (size_t i = 0, end = m_frame_block_size * STEREO_CHANNELS; i < end; ++i)
+    {
+      m_float_conversion_buffer[i] = in[i + frame_index * STEREO_CHANNELS] /
+                                     static_cast<float>(std::numeric_limits<short>::max());
+    }
+
+    // Decode
+    const float* dpl2_fs = m_fsdecoder->decode(m_float_conversion_buffer.data());
+
+    // Add to ring buffer and fix channel mapping
+    // Maybe modify FreeSurround to output the correct mapping?
+    // FreeSurround:
+    // FL | FC | FR | BL | BR | LFE
+    // Most backends:
+    // FL | FR | FC | LFE | BL | BR
+    for (size_t i = 0; i < m_frame_block_size; ++i)
+    {
+      m_decoded_fifo.push(dpl2_fs[i * SURROUND_CHANNELS + 0]);  // LEFTFRONT
+      m_decoded_fifo.push(dpl2_fs[i * SURROUND_CHANNELS + 2]);  // RIGHTFRONT
+      m_decoded_fifo.push(dpl2_fs[i * SURROUND_CHANNELS + 1]);  // CENTREFRONT
+      m_decoded_fifo.push(dpl2_fs[i * SURROUND_CHANNELS + 5]);  // sub/lfe
+      m_decoded_fifo.push(dpl2_fs[i * SURROUND_CHANNELS + 3]);  // LEFTREAR
+      m_decoded_fifo.push(dpl2_fs[i * SURROUND_CHANNELS + 4]);  // RIGHTREAR
+    }
+
+    remaining_frames = remaining_frames - static_cast<int>(m_frame_block_size);
+    frame_index = frame_index + m_frame_block_size;
+  }
+}
+
+void SurroundDecoder::ReceiveFrames(float* out, const size_t num_frames_out)
+{
+  // Copy to output array with desired num_frames_out
+  for (size_t i = 0, num_samples_output = num_frames_out * SURROUND_CHANNELS;
+       i < num_samples_output; ++i)
+  {
+    out[i] = m_decoded_fifo.pop_front();
+  }
+}
+
+}  // namespace AudioCommon