Choose the SDL audio backend when Cubeb reports too high of a latency

src/audio_core/sink/cubeb_sink.cpp

@@ -66,10 +66,10 @@ public:
         const auto latency_error = cubeb_get_min_latency(ctx, &params, &minimum_latency);
         if (latency_error != CUBEB_OK) {
             LOG_CRITICAL(Audio_Sink, "Error getting minimum latency, error: {}", latency_error);
-            minimum_latency = 256U;
+            minimum_latency = TargetSampleCount * 2;
         }
 
-        minimum_latency = std::max(minimum_latency, 256u);
+        minimum_latency = std::max(minimum_latency, TargetSampleCount * 2);
 
         LOG_INFO(Service_Audio,
                  "Opening cubeb stream {} type {} with: rate {} channels {} (system channels {}) "
@@ -326,4 +326,31 @@ std::vector<std::string> ListCubebSinkDevices(bool capture) {
     return device_list;
 }
 
+u32 GetCubebLatency() {
+    cubeb* ctx;
+
+    if (cubeb_init(&ctx, "yuzu Latency Getter", nullptr) != CUBEB_OK) {
+        LOG_CRITICAL(Audio_Sink, "cubeb_init failed");
+        // Return a large latency so we choose SDL instead.
+        return 10000u;
+    }
+
+    cubeb_stream_params params{};
+    params.rate = TargetSampleRate;
+    params.channels = 2;
+    params.format = CUBEB_SAMPLE_S16LE;
+    params.prefs = CUBEB_STREAM_PREF_NONE;
+    params.layout = CUBEB_LAYOUT_STEREO;
+
+    u32 latency{0};
+    const auto latency_error = cubeb_get_min_latency(ctx, &params, &latency);
+    if (latency_error != CUBEB_OK) {
+        LOG_CRITICAL(Audio_Sink, "Error getting minimum latency, error: {}", latency_error);
+        latency = TargetSampleCount * 2;
+    }
+    latency = std::max(latency, TargetSampleCount * 2);
+    cubeb_destroy(ctx);
+    return latency;
+}
+
 } // namespace AudioCore::Sink

src/audio_core/sink/cubeb_sink.h

@@ -96,4 +96,11 @@ private:
  */
 std::vector<std::string> ListCubebSinkDevices(bool capture);
 
+/**
+ * Get the reported latency for this sink.
+ *
+ * @return Minimum latency for this sink.
+ */
+u32 GetCubebLatency();
+
 } // namespace AudioCore::Sink

src/audio_core/sink/sdl2_sink.cpp

@@ -47,11 +47,7 @@ public:
         spec.freq = TargetSampleRate;
         spec.channels = static_cast<u8>(device_channels);
         spec.format = AUDIO_S16SYS;
-        if (type == StreamType::Render) {
-            spec.samples = TargetSampleCount;
-        } else {
-            spec.samples = 1024;
-        }
+        spec.samples = TargetSampleCount * 2;
         spec.callback = &SDLSinkStream::DataCallback;
         spec.userdata = this;
 
@@ -240,4 +236,8 @@ std::vector<std::string> ListSDLSinkDevices(bool capture) {
     return device_list;
 }
 
+u32 GetSDLLatency() {
+    return TargetSampleCount * 2;
+}
+
 } // namespace AudioCore::Sink

src/audio_core/sink/sdl2_sink.h

@@ -87,4 +87,11 @@ private:
  */
 std::vector<std::string> ListSDLSinkDevices(bool capture);
 
+/**
+ * Get the reported latency for this sink.
+ *
+ * @return Minimum latency for this sink.
+ */
+u32 GetSDLLatency();
+
 } // namespace AudioCore::Sink

src/audio_core/sink/sink_details.cpp

@@ -21,58 +21,80 @@ namespace {
 struct SinkDetails {
     using FactoryFn = std::unique_ptr<Sink> (*)(std::string_view);
     using ListDevicesFn = std::vector<std::string> (*)(bool);
+    using LatencyFn = u32 (*)();
 
     /// Name for this sink.
-    const char* id;
+    std::string_view id;
     /// A method to call to construct an instance of this type of sink.
     FactoryFn factory;
     /// A method to call to list available devices.
     ListDevicesFn list_devices;
+    /// Method to get the latency of this backend.
+    LatencyFn latency;
 };
 
 // sink_details is ordered in terms of desirability, with the best choice at the top.
 constexpr SinkDetails sink_details[] = {
 #ifdef HAVE_CUBEB
-    SinkDetails{"cubeb",
-                [](std::string_view device_id) -> std::unique_ptr<Sink> {
-                    return std::make_unique<CubebSink>(device_id);
-                },
-                &ListCubebSinkDevices},
+    SinkDetails{
+        "cubeb",
+        [](std::string_view device_id) -> std::unique_ptr<Sink> {
+            return std::make_unique<CubebSink>(device_id);
+        },
+        &ListCubebSinkDevices,
+        &GetCubebLatency,
+    },
 #endif
 #ifdef HAVE_SDL2
-    SinkDetails{"sdl2",
-                [](std::string_view device_id) -> std::unique_ptr<Sink> {
-                    return std::make_unique<SDLSink>(device_id);
-                },
-                &ListSDLSinkDevices},
+    SinkDetails{
+        "sdl",
+        [](std::string_view device_id) -> std::unique_ptr<Sink> {
+            return std::make_unique<SDLSink>(device_id);
+        },
+        &ListSDLSinkDevices,
+        &GetSDLLatency,
+    },
 #endif
     SinkDetails{"null",
                 [](std::string_view device_id) -> std::unique_ptr<Sink> {
                     return std::make_unique<NullSink>(device_id);
                 },
-                [](bool capture) { return std::vector<std::string>{"null"}; }},
+                [](bool capture) { return std::vector<std::string>{"null"}; }, []() { return 0u; }},
 };
 
 const SinkDetails& GetOutputSinkDetails(std::string_view sink_id) {
-    auto iter =
-        std::find_if(std::begin(sink_details), std::end(sink_details),
-                     [sink_id](const auto& sink_detail) { return sink_detail.id == sink_id; });
+    const auto find_backend{[](std::string_view id) {
+        return std::find_if(std::begin(sink_details), std::end(sink_details),
+                            [&id](const auto& sink_detail) { return sink_detail.id == id; });
+    }};
 
-    if (sink_id == "auto" || iter == std::end(sink_details)) {
-        if (sink_id != "auto") {
-            LOG_ERROR(Audio, "Invalid sink_id {}", sink_id);
+    auto iter = find_backend(sink_id);
+
+    if (sink_id == "auto") {
+        // Auto-select a backend. Prefer CubeB, but it may report a large minimum latency which
+        // causes audio issues, in that case go with SDL.
+#if defined(HAVE_CUBEB) && defined(HAVE_SDL2)
+        iter = find_backend("cubeb");
+        if (iter->latency() > TargetSampleCount * 3) {
+            iter = find_backend("sdl");
         }
-        // Auto-select.
-        // sink_details is ordered in terms of desirability, with the best choice at the front.
+#else
         iter = std::begin(sink_details);
+#endif
+        LOG_INFO(Service_Audio, "Auto-selecting the {} backend", iter->id);
+    }
+
+    if (iter == std::end(sink_details)) {
+        LOG_ERROR(Audio, "Invalid sink_id {}", sink_id);
+        iter = find_backend("null");
     }
 
     return *iter;
 }
 } // Anonymous namespace
 
-std::vector<const char*> GetSinkIDs() {
-    std::vector<const char*> sink_ids(std::size(sink_details));
+std::vector<std::string_view> GetSinkIDs() {
+    std::vector<std::string_view> sink_ids(std::size(sink_details));
 
     std::transform(std::begin(sink_details), std::end(sink_details), std::begin(sink_ids),
                    [](const auto& sink) { return sink.id; });

src/audio_core/sink/sink_details.h

@@ -19,7 +19,7 @@ class Sink;
  *
  * @return Vector of available sink names.
  */
-std::vector<const char*> GetSinkIDs();
+std::vector<std::string_view> GetSinkIDs();
 
 /**
  * Gets the list of devices for a particular sink identified by the given ID.

src/yuzu/configuration/configure_audio.cpp

@@ -161,8 +161,8 @@ void ConfigureAudio::InitializeAudioSinkComboBox() {
     ui->sink_combo_box->clear();
     ui->sink_combo_box->addItem(QString::fromUtf8(AudioCore::Sink::auto_device_name));
 
-    for (const char* id : AudioCore::Sink::GetSinkIDs()) {
-        ui->sink_combo_box->addItem(QString::fromUtf8(id));
+    for (const auto& id : AudioCore::Sink::GetSinkIDs()) {
+        ui->sink_combo_box->addItem(QString::fromUtf8(id.data(), static_cast<s32>(id.length())));
     }
 }