audio_core: Implement Sink and SinkStream interfaces with cubeb.

CMakeLists.txt

@@ -17,6 +17,8 @@ CMAKE_DEPENDENT_OPTION(YUZU_USE_BUNDLED_QT "Download bundled Qt binaries" ON "EN
 
 option(YUZU_USE_BUNDLED_UNICORN "Build/Download bundled Unicorn" ON)
 
+option(ENABLE_CUBEB "Enables the cubeb audio backend" ON)
+
 if(NOT EXISTS ${CMAKE_SOURCE_DIR}/.git/hooks/pre-commit)
     message(STATUS "Copying pre-commit hook")
     file(COPY hooks/pre-commit

externals/CMakeLists.txt

@@ -54,3 +54,9 @@ endif()
 # Opus
 add_subdirectory(opus)
 target_include_directories(opus INTERFACE ./opus/include)
+
+# Cubeb
+if(ENABLE_CUBEB)
+    set(BUILD_TESTS OFF CACHE BOOL "")
+    add_subdirectory(cubeb)
+endif()

src/audio_core/CMakeLists.txt

@@ -2,6 +2,8 @@ add_library(audio_core STATIC
     audio_out.cpp
     audio_out.h
     buffer.h
+    cubeb_sink.cpp
+    cubeb_sink.h
     null_sink.h
     stream.cpp
     stream.h
@@ -14,3 +16,8 @@ add_library(audio_core STATIC
 create_target_directory_groups(audio_core)
 
 target_link_libraries(audio_core PUBLIC common core)
+
+if(ENABLE_CUBEB)
+    target_link_libraries(audio_core PRIVATE cubeb)
+    target_compile_definitions(audio_core PRIVATE -DHAVE_CUBEB=1)
+endif()

src/audio_core/audio_out.cpp

@@ -3,6 +3,8 @@
 // Refer to the license.txt file included.
 
 #include "audio_core/audio_out.h"
+#include "audio_core/sink.h"
+#include "audio_core/sink_details.h"
 #include "common/assert.h"
 #include "common/logging/log.h"
 
@@ -26,9 +28,14 @@ static Stream::Format ChannelsToStreamFormat(u32 num_channels) {
 
 StreamPtr AudioOut::OpenStream(u32 sample_rate, u32 num_channels,
                                Stream::ReleaseCallback&& release_callback) {
-    streams.push_back(std::make_shared<Stream>(sample_rate, ChannelsToStreamFormat(num_channels),
-                                               std::move(release_callback)));
-    return streams.back();
+    if (!sink) {
+        const SinkDetails& sink_details = GetSinkDetails("auto");
+        sink = sink_details.factory("");
+    }
+
+    return std::make_shared<Stream>(sample_rate, ChannelsToStreamFormat(num_channels),
+                                    std::move(release_callback),
+                                    sink->AcquireSinkStream(sample_rate, num_channels));
 }
 
 std::vector<u64> AudioOut::GetTagsAndReleaseBuffers(StreamPtr stream, size_t max_count) {

src/audio_core/audio_out.h

@@ -8,6 +8,7 @@
 #include <vector>
 
 #include "audio_core/buffer.h"
+#include "audio_core/sink.h"
 #include "audio_core/stream.h"
 #include "common/common_types.h"
 
@@ -36,7 +37,6 @@ public:
 
 private:
     SinkPtr sink;
-    std::vector<StreamPtr> streams;
 };
 
 } // namespace AudioCore

src/audio_core/cubeb_sink.cpp

@@ -0,0 +1,190 @@
+// Copyright 2018 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <algorithm>
+#include <cstring>
+
+#include "audio_core/cubeb_sink.h"
+#include "audio_core/stream.h"
+#include "common/logging/log.h"
+
+namespace AudioCore {
+
+class SinkStreamImpl final : public SinkStream {
+public:
+    SinkStreamImpl(cubeb* ctx, cubeb_devid output_device) : ctx{ctx} {
+        cubeb_stream_params params;
+        params.rate = 48000;
+        params.channels = GetNumChannels();
+        params.format = CUBEB_SAMPLE_S16NE;
+        params.layout = CUBEB_LAYOUT_STEREO;
+
+        u32 minimum_latency = 0;
+        if (cubeb_get_min_latency(ctx, &params, &minimum_latency) != CUBEB_OK) {
+            LOG_CRITICAL(Audio_Sink, "Error getting minimum latency");
+        }
+
+        if (cubeb_stream_init(ctx, &stream_backend, "yuzu Audio Output", nullptr, nullptr,
+                              output_device, &params, std::max(512u, minimum_latency),
+                              &SinkStreamImpl::DataCallback, &SinkStreamImpl::StateCallback,
+                              this) != CUBEB_OK) {
+            LOG_CRITICAL(Audio_Sink, "Error initializing cubeb stream");
+            return;
+        }
+
+        if (cubeb_stream_start(stream_backend) != CUBEB_OK) {
+            LOG_CRITICAL(Audio_Sink, "Error starting cubeb stream");
+            return;
+        }
+    }
+
+    ~SinkStreamImpl() {
+        if (!ctx) {
+            return;
+        }
+
+        if (cubeb_stream_stop(stream_backend) != CUBEB_OK) {
+            LOG_CRITICAL(Audio_Sink, "Error stopping cubeb stream");
+        }
+
+        cubeb_stream_destroy(stream_backend);
+    }
+
+    void EnqueueSamples(u32 num_channels, const s16* samples, size_t sample_count) override {
+        if (!ctx) {
+            return;
+        }
+
+        queue.reserve(queue.size() + sample_count * GetNumChannels());
+
+        if (num_channels == 2) {
+            // Copy as-is
+            std::copy(samples, samples + sample_count * GetNumChannels(),
+                      std::back_inserter(queue));
+        } else if (num_channels == 6) {
+            // Downsample 6 channels to 2
+            const size_t sample_count_copy_size = sample_count * num_channels * 2;
+            queue.reserve(sample_count_copy_size);
+            for (size_t i = 0; i < sample_count * num_channels; i += num_channels) {
+                queue.push_back(samples[i]);
+                queue.push_back(samples[i + 1]);
+            }
+        } else {
+            ASSERT_MSG(false, "Unimplemented");
+        }
+    }
+
+    u32 GetNumChannels() const {
+        // Only support 2-channel stereo output for now
+        return 2;
+    }
+
+private:
+    std::vector<std::string> device_list;
+
+    cubeb* ctx{};
+    cubeb_stream* stream_backend{};
+
+    std::vector<s16> queue;
+
+    static long DataCallback(cubeb_stream* stream, void* user_data, const void* input_buffer,
+                             void* output_buffer, long num_frames);
+    static void StateCallback(cubeb_stream* stream, void* user_data, cubeb_state state);
+};
+
+CubebSink::CubebSink(std::string target_device_name) {
+    if (cubeb_init(&ctx, "yuzu", nullptr) != CUBEB_OK) {
+        LOG_CRITICAL(Audio_Sink, "cubeb_init failed");
+        return;
+    }
+
+    if (target_device_name != auto_device_name && !target_device_name.empty()) {
+        cubeb_device_collection collection;
+        if (cubeb_enumerate_devices(ctx, CUBEB_DEVICE_TYPE_OUTPUT, &collection) != CUBEB_OK) {
+            LOG_WARNING(Audio_Sink, "Audio output device enumeration not supported");
+        } else {
+            const auto collection_end{collection.device + collection.count};
+            const auto device{std::find_if(collection.device, collection_end,
+                                           [&](const cubeb_device_info& device) {
+                                               return target_device_name == device.friendly_name;
+                                           })};
+            if (device != collection_end) {
+                output_device = device->devid;
+            }
+            cubeb_device_collection_destroy(ctx, &collection);
+        }
+    }
+}
+
+CubebSink::~CubebSink() {
+    if (!ctx) {
+        return;
+    }
+
+    for (auto& sink_stream : sink_streams) {
+        sink_stream.reset();
+    }
+
+    cubeb_destroy(ctx);
+}
+
+SinkStream& CubebSink::AcquireSinkStream(u32 sample_rate, u32 num_channels) {
+    sink_streams.push_back(std::make_unique<SinkStreamImpl>(ctx, output_device));
+    return *sink_streams.back();
+}
+
+long SinkStreamImpl::DataCallback(cubeb_stream* stream, void* user_data, const void* input_buffer,
+                                  void* output_buffer, long num_frames) {
+    SinkStreamImpl* impl = static_cast<SinkStreamImpl*>(user_data);
+    u8* buffer = reinterpret_cast<u8*>(output_buffer);
+
+    if (!impl) {
+        return {};
+    }
+
+    const size_t frames_to_write{
+        std::min(impl->queue.size() / impl->GetNumChannels(), static_cast<size_t>(num_frames))};
+
+    memcpy(buffer, impl->queue.data(), frames_to_write * sizeof(s16) * impl->GetNumChannels());
+    impl->queue.erase(impl->queue.begin(),
+                      impl->queue.begin() + frames_to_write * impl->GetNumChannels());
+
+    if (frames_to_write < num_frames) {
+        // Fill the rest of the frames with silence
+        memset(buffer + frames_to_write * sizeof(s16) * impl->GetNumChannels(), 0,
+               (num_frames - frames_to_write) * sizeof(s16) * impl->GetNumChannels());
+    }
+
+    return num_frames;
+}
+
+void SinkStreamImpl::StateCallback(cubeb_stream* stream, void* user_data, cubeb_state state) {}
+
+std::vector<std::string> ListCubebSinkDevices() {
+    std::vector<std::string> device_list;
+    cubeb* ctx;
+
+    if (cubeb_init(&ctx, "Citra Device Enumerator", nullptr) != CUBEB_OK) {
+        LOG_CRITICAL(Audio_Sink, "cubeb_init failed");
+        return {};
+    }
+
+    cubeb_device_collection collection;
+    if (cubeb_enumerate_devices(ctx, CUBEB_DEVICE_TYPE_OUTPUT, &collection) != CUBEB_OK) {
+        LOG_WARNING(Audio_Sink, "Audio output device enumeration not supported");
+    } else {
+        for (size_t i = 0; i < collection.count; i++) {
+            const cubeb_device_info& device = collection.device[i];
+            if (device.friendly_name) {
+                device_list.emplace_back(device.friendly_name);
+            }
+        }
+        cubeb_device_collection_destroy(ctx, &collection);
+    }
+
+    cubeb_destroy(ctx);
+    return device_list;
+}
+
+} // namespace AudioCore

src/audio_core/cubeb_sink.h

@@ -0,0 +1,31 @@
+// Copyright 2018 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <string>
+#include <vector>
+
+#include <cubeb/cubeb.h>
+
+#include "audio_core/sink.h"
+
+namespace AudioCore {
+
+class CubebSink final : public Sink {
+public:
+    explicit CubebSink(std::string device_id);
+    ~CubebSink() override;
+
+    SinkStream& AcquireSinkStream(u32 sample_rate, u32 num_channels) override;
+
+private:
+    cubeb* ctx{};
+    cubeb_devid output_device{};
+    std::vector<SinkStreamPtr> sink_streams;
+};
+
+std::vector<std::string> ListCubebSinkDevices();
+
+} // namespace AudioCore

src/audio_core/sink_details.cpp

@@ -8,12 +8,18 @@
 #include <vector>
 #include "audio_core/null_sink.h"
 #include "audio_core/sink_details.h"
+#ifdef HAVE_CUBEB
+#include "audio_core/cubeb_sink.h"
+#endif
 #include "common/logging/log.h"
 
 namespace AudioCore {
 
 // g_sink_details is ordered in terms of desirability, with the best choice at the top.
 const std::vector<SinkDetails> g_sink_details = {
+#ifdef HAVE_CUBEB
+    SinkDetails{"cubeb", &std::make_unique<CubebSink, std::string>, &ListCubebSinkDevices},
+#endif
     SinkDetails{"null", &std::make_unique<NullSink, std::string>,
                 [] { return std::vector<std::string>{"null"}; }},
 };

src/audio_core/stream.cpp

@@ -7,6 +7,8 @@
 #include "core/core_timing.h"
 #include "core/core_timing_util.h"
 
+#include "audio_core/sink.h"
+#include "audio_core/sink_details.h"
 #include "audio_core/stream.h"
 
 namespace AudioCore {
@@ -31,6 +33,11 @@ u32 Stream::GetSampleSize() const {
     return GetNumChannels() * 2;
 }
 
+Stream::Stream(u32 sample_rate, Format format, ReleaseCallback&& release_callback,
+               SinkStream& sink_stream)
+    : sample_rate{sample_rate}, format{format}, release_callback{std::move(release_callback)},
+      sink_stream{sink_stream} {
+
     release_event = CoreTiming::RegisterEvent(
         "Stream::Release", [this](u64 userdata, int cycles_late) { ReleaseActiveBuffer(); });
 }
@@ -68,6 +75,10 @@ void Stream::PlayNextBuffer() {
     active_buffer = queued_buffers.front();
     queued_buffers.pop();
 
+    sink_stream.EnqueueSamples(GetNumChannels(),
+                               reinterpret_cast<const s16*>(active_buffer->GetData().data()),
+                               active_buffer->GetData().size() / GetSampleSize());
+
     CoreTiming::ScheduleEventThreadsafe(GetBufferReleaseCycles(*active_buffer), release_event, {});
 }
 

src/audio_core/stream.h

@@ -10,6 +10,7 @@
 #include <queue>
 
 #include "audio_core/buffer.h"
+#include "audio_core/sink_stream.h"
 #include "common/assert.h"
 #include "common/common_types.h"
 #include "core/core_timing.h"
@@ -31,7 +32,8 @@ public:
     /// Callback function type, used to change guest state on a buffer being released
     using ReleaseCallback = std::function<void()>;
 
-    Stream(int sample_rate, Format format, ReleaseCallback&& release_callback);
+    Stream(u32 sample_rate, Format format, ReleaseCallback&& release_callback,
+           SinkStream& sink_stream);
 
     /// Plays the audio stream
     void Play();
@@ -85,7 +87,7 @@ private:
     /// Gets the number of core cycles when the specified buffer will be released
     s64 GetBufferReleaseCycles(const Buffer& buffer) const;
 
-    int sample_rate;                        ///< Sample rate of the stream
+    u32 sample_rate;                        ///< Sample rate of the stream
     Format format;                          ///< Format of the stream
     ReleaseCallback release_callback;       ///< Buffer release callback for the stream
     State state{State::Stopped};            ///< Playback state of the stream
@@ -93,6 +95,7 @@ private:
     BufferPtr active_buffer;                ///< Actively playing buffer in the stream
     std::queue<BufferPtr> queued_buffers;   ///< Buffers queued to be played in the stream
     std::queue<BufferPtr> released_buffers; ///< Buffers recently released from the stream
+    SinkStream& sink_stream;                ///< Output sink for the stream
 };
 
 using StreamPtr = std::shared_ptr<Stream>;