Rework audio output, connecting AudioOut into coretiming to fix desync during heavy loads.

src/audio_core/device/audio_buffer.h

@@ -8,6 +8,10 @@
 namespace AudioCore {
 
 struct AudioBuffer {
+    /// Timestamp this buffer started playing.
+    u64 start_timestamp;
+    /// Timestamp this buffer should finish playing.
+    u64 end_timestamp;
     /// Timestamp this buffer completed playing.
     s64 played_timestamp;
     /// Game memory address for these samples.

src/audio_core/device/audio_buffers.h

@@ -58,6 +58,7 @@ public:
             if (index < 0) {
                 index += N;
             }
+
             out_buffers.push_back(buffers[index]);
             registered_count++;
             registered_index = (registered_index + 1) % append_limit;
@@ -100,7 +101,7 @@ public:
             }
 
             // Check with the backend if this buffer can be released yet.
-            if (!session.IsBufferConsumed(buffers[index].tag)) {
+            if (!session.IsBufferConsumed(buffers[index])) {
                 break;
             }
 
@@ -280,6 +281,16 @@ public:
         return true;
     }
 
+    u64 GetNextTimestamp() const {
+        // Iterate backwards through the buffer queue, and take the most recent buffer's end
+        std::scoped_lock l{lock};
+        auto index{appended_index - 1};
+        if (index < 0) {
+            index += append_limit;
+        }
+        return buffers[index].end_timestamp;
+    }
+
 private:
     /// Buffer lock
     mutable std::recursive_mutex lock{};

src/audio_core/device/device_session.cpp

@@ -7,11 +7,20 @@
 #include "audio_core/device/device_session.h"
 #include "audio_core/sink/sink_stream.h"
 #include "core/core.h"
+#include "core/core_timing.h"
 #include "core/memory.h"
 
 namespace AudioCore {
 
-DeviceSession::DeviceSession(Core::System& system_) : system{system_} {}
+using namespace std::literals;
+constexpr auto INCREMENT_TIME{5ms};
+
+DeviceSession::DeviceSession(Core::System& system_)
+    : system{system_}, thread_event{Core::Timing::CreateEvent(
+                           "AudioOutSampleTick",
+                           [this](std::uintptr_t, s64 time, std::chrono::nanoseconds) {
+                               return ThreadFunc();
+                           })} {}
 
 DeviceSession::~DeviceSession() {
     Finalize();
@@ -50,20 +59,21 @@ void DeviceSession::Finalize() {
 }
 
 void DeviceSession::Start() {
-    stream->SetPlayedSampleCount(played_sample_count);
-    stream->Start();
+    if (stream) {
+        stream->Start();
+        system.CoreTiming().ScheduleLoopingEvent(std::chrono::nanoseconds::zero(), INCREMENT_TIME,
+                                                 thread_event);
+    }
 }
 
 void DeviceSession::Stop() {
     if (stream) {
-        played_sample_count = stream->GetPlayedSampleCount();
         stream->Stop();
+        system.CoreTiming().UnscheduleEvent(thread_event, {});
     }
 }
 
 void DeviceSession::AppendBuffers(std::span<AudioBuffer> buffers) const {
-    auto& memory{system.Memory()};
-
     for (size_t i = 0; i < buffers.size(); i++) {
         Sink::SinkBuffer new_buffer{
             .frames = buffers[i].size / (channel_count * sizeof(s16)),
@@ -77,7 +87,7 @@ void DeviceSession::AppendBuffers(std::span<AudioBuffer> buffers) const {
             stream->AppendBuffer(new_buffer, samples);
         } else {
             std::vector<s16> samples(buffers[i].size / sizeof(s16));
-            memory.ReadBlockUnsafe(buffers[i].samples, samples.data(), buffers[i].size);
+            system.Memory().ReadBlockUnsafe(buffers[i].samples, samples.data(), buffers[i].size);
             stream->AppendBuffer(new_buffer, samples);
         }
     }
@@ -85,17 +95,13 @@ void DeviceSession::AppendBuffers(std::span<AudioBuffer> buffers) const {
 
 void DeviceSession::ReleaseBuffer(AudioBuffer& buffer) const {
     if (type == Sink::StreamType::In) {
-        auto& memory{system.Memory()};
         auto samples{stream->ReleaseBuffer(buffer.size / sizeof(s16))};
-        memory.WriteBlockUnsafe(buffer.samples, samples.data(), buffer.size);
+        system.Memory().WriteBlockUnsafe(buffer.samples, samples.data(), buffer.size);
     }
 }
 
-bool DeviceSession::IsBufferConsumed(u64 tag) const {
-    if (stream) {
-        return stream->IsBufferConsumed(tag);
-    }
-    return true;
+bool DeviceSession::IsBufferConsumed(AudioBuffer& buffer) const {
+    return played_sample_count >= buffer.end_timestamp;
 }
 
 void DeviceSession::SetVolume(f32 volume) const {
@@ -105,10 +111,22 @@ void DeviceSession::SetVolume(f32 volume) const {
 }
 
 u64 DeviceSession::GetPlayedSampleCount() const {
-    if (stream) {
-        return stream->GetPlayedSampleCount();
+    return played_sample_count;
+}
+
+std::optional<std::chrono::nanoseconds> DeviceSession::ThreadFunc() {
+    // Add 5ms of samples at a 48K sample rate.
+    played_sample_count += 48'000 * INCREMENT_TIME / 1s;
+    if (type == Sink::StreamType::Out) {
+        system.AudioCore().GetAudioManager().SetEvent(Event::Type::AudioOutManager, true);
+    } else {
+        system.AudioCore().GetAudioManager().SetEvent(Event::Type::AudioInManager, true);
     }
-    return 0;
+    return std::nullopt;
+}
+
+void DeviceSession::SetRingSize(u32 ring_size) {
+    stream->SetRingSize(ring_size);
 }
 
 } // namespace AudioCore

src/audio_core/device/device_session.h

@@ -3,6 +3,9 @@
 
 #pragma once
 
+#include <chrono>
+#include <memory>
+#include <optional>
 #include <span>
 
 #include "audio_core/common/common.h"
@@ -11,9 +14,13 @@
 
 namespace Core {
 class System;
-}
+namespace Timing {
+struct EventType;
+} // namespace Timing
+} // namespace Core
 
 namespace AudioCore {
+
 namespace Sink {
 class SinkStream;
 struct SinkBuffer;
@@ -70,7 +77,7 @@ public:
      * @param tag - Unqiue tag of the buffer to check.
      * @return true if the buffer has been consumed, otherwise false.
      */
-    bool IsBufferConsumed(u64 tag) const;
+    bool IsBufferConsumed(AudioBuffer& buffer) const;
 
     /**
      * Start this device session, starting the backend stream.
@@ -96,6 +103,16 @@ public:
      */
     u64 GetPlayedSampleCount() const;
 
+    /*
+     * CoreTiming callback to increment played_sample_count over time.
+     */
+    std::optional<std::chrono::nanoseconds> ThreadFunc();
+
+    /*
+     * Set the size of the ring buffer.
+     */
+    void SetRingSize(u32 ring_size);
+
 private:
     /// System
     Core::System& system;
@@ -118,9 +135,13 @@ private:
     /// Applet resource user id of this device session
     u64 applet_resource_user_id{};
     /// Total number of samples played by this device session
-    u64 played_sample_count{};
+    std::atomic<u64> played_sample_count{};
+    /// Event increasing the played sample count every 5ms
+    std::shared_ptr<Core::Timing::EventType> thread_event;
     /// Is this session initialised?
     bool initialized{};
+    /// Buffer queue
+    std::vector<AudioBuffer> buffer_queue{};
 };
 
 } // namespace AudioCore