Added FreeSurround support to the PulseAudio backend

CMakeLists.txt

@@ -611,11 +611,9 @@ else()
   set(PNG png)
 endif()
 
-find_package(OpenAL)
-if(OPENAL_FOUND)
-  message(STATUS "Using static FreeSurround from Externals")
-  add_subdirectory(Externals/FreeSurround)
-endif()
+# There is no system FreeSurround library available
+message(STATUS "Using static FreeSurround from Externals")
+add_subdirectory(Externals/FreeSurround)
 
 # Using static soundtouch from Externals
 # Unable to use system soundtouch library: We require shorts, not floats.

Source/Core/AudioCommon/CMakeLists.txt

@@ -55,7 +55,7 @@ if(ENABLE_PULSEAUDIO)
   if(PULSEAUDIO_FOUND)
     message(STATUS "PulseAudio found, enabling PulseAudio sound backend")
     target_sources(audiocommon PRIVATE PulseAudioStream.cpp)
-    target_link_libraries(audiocommon PRIVATE PulseAudio::PulseAudio)
+    target_link_libraries(audiocommon PRIVATE PulseAudio::PulseAudio FreeSurround)
     target_compile_definitions(audiocommon PRIVATE HAVE_PULSEAUDIO=1)
   else()
     message(STATUS "PulseAudio NOT found, disabling PulseAudio sound backend")

Source/Core/AudioCommon/PulseAudioStream.cpp

@@ -4,16 +4,17 @@
 
 #include <cstring>
 
-#include "AudioCommon/DPL2Decoder.h"
 #include "AudioCommon/PulseAudioStream.h"
 #include "Common/CommonTypes.h"
 #include "Common/Logging/Log.h"
 #include "Common/Thread.h"
 #include "Core/ConfigManager.h"
+#include "FreeSurround/FreeSurroundDecoder.h"
 
 namespace
 {
 const size_t BUFFER_SAMPLES = 512;  // ~10 ms - needs to be at least 240 for surround
+static DPL2FSDecoder fsdecoder;
 }
 
 PulseAudio::PulseAudio() : m_thread(), m_run_thread()
@@ -23,15 +24,17 @@ PulseAudio::PulseAudio() : m_thread(), m_run_thread()
 bool PulseAudio::Start()
 {
   m_stereo = !SConfig::GetInstance().bDPL2Decoder;
-  m_channels = m_stereo ? 2 : 5;  // will tell PA we use a Stereo or 5.0 channel setup
+  m_channels = m_stereo ? 2 : 6;  // will tell PA we use a Stereo or 5.0 channel setup
 
   NOTICE_LOG(AUDIO, "PulseAudio backend using %d channels", m_channels);
 
   m_run_thread.Set();
   m_thread = std::thread(&PulseAudio::SoundLoop, this);
 
-  // Initialize DPL2 parameters
-  DPL2Reset();
+  // Initialize FS decoder
+  fsdecoder.Init();
+  fsdecoder.set_block_size(BUFFER_SAMPLES);
+  fsdecoder.set_sample_rate(m_mixer->GetSampleRate());
 
   return true;
 }
@@ -105,12 +108,15 @@ bool PulseAudio::PulseInit()
     m_bytespersample = sizeof(float);
 
     channel_map_p = &channel_map;  // explicit channel map:
-    channel_map.channels = 5;
+    channel_map.channels = 6;
+    // FreeSurround:
+    // FL | FC | FR | BL | BR | LFE
     channel_map.map[0] = PA_CHANNEL_POSITION_FRONT_LEFT;
-    channel_map.map[1] = PA_CHANNEL_POSITION_FRONT_RIGHT;
-    channel_map.map[2] = PA_CHANNEL_POSITION_FRONT_CENTER;
+    channel_map.map[1] = PA_CHANNEL_POSITION_FRONT_CENTER;
+    channel_map.map[2] = PA_CHANNEL_POSITION_FRONT_RIGHT;
     channel_map.map[3] = PA_CHANNEL_POSITION_REAR_LEFT;
     channel_map.map[4] = PA_CHANNEL_POSITION_REAR_RIGHT;
+    channel_map.map[5] = PA_CHANNEL_POSITION_LFE;
   }
   ss.channels = m_channels;
   ss.rate = m_mixer->GetSampleRate();
@@ -194,32 +200,57 @@ void PulseAudio::WriteCallback(pa_stream* s, size_t length)
   }
   else
   {
-    // get a floating point mix
-    s16 s16buffer_stereo[frames * 2];
-    m_mixer->Mix(s16buffer_stereo, frames);  // implicitly mixes to 16-bit stereo
-
-    float floatbuffer_stereo[frames * 2];
-    // s16 to float
-    for (int i = 0; i < frames * 2; ++i)
+    if (m_channels == 6)  // Extract dpl2/5.1 Surround
     {
-      floatbuffer_stereo[i] = s16buffer_stereo[i] / float(1 << 15);
-    }
+      // Calculate how many times we need to request the FS decoder
+      int num_fs_dec_requests = 0;
+      if (m_floatsurround_buffer_queue.size() < static_cast<u32>(frames * m_channels))
+      {
+        long num_frames_remaining =
+            frames - static_cast<long>(m_floatsurround_buffer_queue.size() / m_channels);
+        while (num_frames_remaining > 0)
+        {
+          ++num_fs_dec_requests;
+          num_frames_remaining = num_frames_remaining - BUFFER_SAMPLES;
+        }
+      }
 
-    if (m_channels == 5)  // Extract dpl2/5.0 Surround
-    {
-      float floatbuffer_6chan[frames * 6];
-      // DPL2Decode output: LEFTFRONT, RIGHTFRONT, CENTREFRONT, (sub), LEFTREAR, RIGHTREAR
-      DPL2Decode(floatbuffer_stereo, frames, floatbuffer_6chan);
-
-      // Discard the subwoofer channel - DPL2Decode generates a pretty
-      // good 5.0 but not a good 5.1 output.
-      const int dpl2_to_5chan[] = {0, 1, 2, 4, 5};
-      for (int i = 0; i < frames; ++i)
+      while (num_fs_dec_requests > 0)
       {
-        for (int j = 0; j < m_channels; ++j)
+        // get a floating point mix
+        s16 s16buffer_stereo[frames * 2];
+        m_mixer->Mix(s16buffer_stereo, BUFFER_SAMPLES);  // implicitly mixes to 16-bit stereo
+
+        float floatbuffer_stereo[frames * 2];
+        // s16 to float
+        for (int i = 0; i < frames * 2; ++i)
         {
-          ((float*)buffer)[m_channels * i + j] = floatbuffer_6chan[6 * i + dpl2_to_5chan[j]];
+          floatbuffer_stereo[i] = s16buffer_stereo[i] / static_cast<float>(INT16_MAX);
         }
+
+        // FSDPL2Decode
+        float* dpl2_fs = fsdecoder.decode(floatbuffer_stereo);
+
+        // Add to queue. PA was already initialized with the correct
+        // channel mapping.
+        for (u32 i = 0; i < BUFFER_SAMPLES; ++i)
+        {
+          m_floatsurround_buffer_queue.push(dpl2_fs[i * m_channels + 0 /*LEFTFRONT*/]);
+          m_floatsurround_buffer_queue.push(dpl2_fs[i * m_channels + 1 /*CENTREFRONT*/]);
+          m_floatsurround_buffer_queue.push(dpl2_fs[i * m_channels + 2 /*RIGHTFRONT*/]);
+          m_floatsurround_buffer_queue.push(dpl2_fs[i * m_channels + 3 /*LEFTREAR*/]);
+          m_floatsurround_buffer_queue.push(dpl2_fs[i * m_channels + 4 /*RIGHTREAR*/]);
+          m_floatsurround_buffer_queue.push(dpl2_fs[i * m_channels + 5 /*sub/lfe*/]);
+        }
+
+        --num_fs_dec_requests;
+      }
+
+      // Copy to output array with desired number of frames
+      for (long i = 0, num_samples = frames * m_channels; i < num_samples; ++i)
+      {
+        static_cast<float*>(buffer)[i] = m_floatsurround_buffer_queue.front();
+        m_floatsurround_buffer_queue.pop();
       }
     }
     else

Source/Core/AudioCommon/PulseAudioStream.h

@@ -4,6 +4,8 @@
 
 #pragma once
 
+#include <queue>
+
 #if defined(HAVE_PULSEAUDIO) && HAVE_PULSEAUDIO
 #include <pulse/pulseaudio.h>
 #endif
@@ -45,6 +47,7 @@ class PulseAudio final : public SoundStream
   bool m_stereo;  // stereo, else surround
   int m_bytespersample;
   int m_channels;
+  std::queue<float> m_floatsurround_buffer_queue;
 
   int m_pa_error;
   int m_pa_connected;