Optimize Audio by using Circular Buffers, Handle Device Disconnection and Fix Some Bugs

This optimizes a lot of audio by using a circular buffer rather than queues. In addition to handling device disconnection using oboe callbacks and fix bugs in regards to audio saturation.

app/src/main/cpp/skyline/audio.cpp

@@ -5,67 +5,68 @@
 
 namespace skyline::audio {
     Audio::Audio(const DeviceState &state) : state(state), oboe::AudioStreamCallback() {
-        oboe::AudioStreamBuilder builder;
+        builder.setChannelCount(constant::ChannelCount);
-
+        builder.setSampleRate(constant::SampleRate);
-        builder.setChannelCount(constant::ChannelCount)
+        builder.setFormat(constant::PcmFormat);
-            ->setSampleRate(constant::SampleRate)
+        builder.setFramesPerCallback(constant::MixBufferSize);
-            ->setFormat(constant::PcmFormat)
+        builder.setUsage(oboe::Usage::Game);
-            ->setCallback(this)
+        builder.setCallback(this);
-            ->openManagedStream(outputStream);
 
+        builder.openManagedStream(outputStream);
         outputStream->requestStart();
     }
 
-    Audio::~Audio() {
-        outputStream->close();
-    }
-
     std::shared_ptr<AudioTrack> Audio::OpenTrack(const int channelCount, const int sampleRate, const std::function<void()> &releaseCallback) {
-        std::shared_ptr<AudioTrack> track = std::make_shared<AudioTrack>(channelCount, sampleRate, releaseCallback);
+        std::lock_guard trackGuard(trackMutex);
+
+        auto track = std::make_shared<AudioTrack>(channelCount, sampleRate, releaseCallback);
         audioTracks.push_back(track);
 
         return track;
     }
 
     void Audio::CloseTrack(std::shared_ptr<AudioTrack> &track) {
+        std::lock_guard trackGuard(trackMutex);
+
         audioTracks.erase(std::remove(audioTracks.begin(), audioTracks.end(), track), audioTracks.end());
         track.reset();
     }
 
     oboe::DataCallbackResult Audio::onAudioReady(oboe::AudioStream *audioStream, void *audioData, int32_t numFrames) {
         i16 *destBuffer = static_cast<i16 *>(audioData);
-        uint setIndex = 0;
+        size_t streamSamples = static_cast<size_t>(numFrames) * audioStream->getChannelCount();
-        size_t sampleI16Size = static_cast<size_t>(numFrames) * audioStream->getChannelCount();
+        size_t writtenSamples = 0;
+
+        std::unique_lock trackLock(trackMutex);
 
         for (auto &track : audioTracks) {
             if (track->playbackState == AudioOutState::Stopped)
                 continue;
 
-            track->bufferLock.lock();
+            std::lock_guard bufferGuard(track->bufferLock);
 
-            std::queue<i16> &srcBuffer = track->sampleQueue;
+            auto trackSamples = track->samples.Read(destBuffer, streamSamples, [](i16 *source, i16 *destination) {
-            size_t amount = std::min(srcBuffer.size(), sampleI16Size);
+                *destination = Saturate<i16, i32>(static_cast<u32>(*destination) + static_cast<u32>(*source));
+            }, writtenSamples);
 
-            for (size_t i = 0; i < amount; i++) {
+            writtenSamples = std::max(trackSamples, writtenSamples);
-                if (setIndex == i) {
-                    destBuffer[i] = srcBuffer.front();
-                    setIndex++;
-                } else {
-                    destBuffer[i] += srcBuffer.front();
-                }
 
-                srcBuffer.pop();
+            track->sampleCounter += trackSamples;
-            }
-
-            track->sampleCounter += amount;
             track->CheckReleasedBuffers();
-
-            track->bufferLock.unlock();
         }
 
-        if (sampleI16Size > setIndex)
+        trackLock.unlock();
-            memset(destBuffer, 0, (sampleI16Size - setIndex) * 2);
+
+        if (streamSamples > writtenSamples)
+            memset(destBuffer + writtenSamples, 0, (streamSamples - writtenSamples) * sizeof(i16));
 
         return oboe::DataCallbackResult::Continue;
     }
+
+    void Audio::onErrorAfterClose(oboe::AudioStream *audioStream, oboe::Result error) {
+        if (error == oboe::Result::ErrorDisconnected) {
+            builder.openManagedStream(outputStream);
+            outputStream->requestStart();
+        }
+    }
 }

app/src/main/cpp/skyline/audio.h

@@ -17,17 +17,14 @@ namespace skyline::audio {
     class Audio : public oboe::AudioStreamCallback {
       private:
         const DeviceState &state; //!< The state of the device
+        oboe::AudioStreamBuilder builder; //!< The audio stream builder, used to open
         oboe::ManagedStream outputStream; //!< The output oboe audio stream
-        std::vector<std::shared_ptr<audio::AudioTrack>> audioTracks; //!< Vector containing a pointer of every open audio track
+        std::vector<std::shared_ptr<audio::AudioTrack>> audioTracks; //!< A vector of shared_ptr to every open audio track
+        Mutex trackMutex; //!< This mutex is used to ensure that audioTracks isn't modified while it is being used
 
       public:
         Audio(const DeviceState &state);
 
-        /**
-         * @brief The destructor for the audio class
-         */
-        ~Audio();
-
         /**
          * @brief Opens a new track that can be used to play sound
          * @param channelCount The amount channels that are present in the track
@@ -50,5 +47,12 @@ namespace skyline::audio {
          * @param numFrames The amount of frames the sample data needs to contain
          */
         oboe::DataCallbackResult onAudioReady(oboe::AudioStream *audioStream, void *audioData, int32_t numFrames);
+
+        /**
+         * @brief The callback oboe uses to notify the application about stream closure
+         * @param audioStream The audio stream we are being called by
+         * @param error The error due to which the stream is being closed
+         */
+        void onErrorAfterClose(oboe::AudioStream *audioStream, oboe::Result error);
     };
 }

app/src/main/cpp/skyline/audio/common.h

@@ -5,12 +5,14 @@
 
 #include <oboe/Oboe.h>
 #include <common.h>
+#include <array>
 
 namespace skyline {
     namespace constant {
         constexpr auto SampleRate = 48000; //!< The common sampling rate to use for audio output
         constexpr auto ChannelCount = 2; //!< The common amount of channels to use for audio output
         constexpr auto PcmFormat = oboe::AudioFormat::I16; //!< The common PCM data format to use for audio output
+        constexpr size_t MixBufferSize = 960; //!< The size of the mix buffer by default
     };
 
     namespace audio {
@@ -44,5 +46,161 @@ namespace skyline {
             u64 finalSample; //!< The final sample this buffer will be played in
             bool released; //!< If the buffer has been released
         };
+
+        /**
+         * @brief This saturates the specified value according to the numeric limits of Out
+         * @tparam Out The return value type and the numeric limit clamp
+         * @tparam Intermediate The intermediate type that is converted to from In before clamping
+         * @tparam In The input value type
+         * @param value The value to saturate
+         * @return The saturated value
+         */
+        template<typename Out, typename Intermediate, typename In>
+        inline Out Saturate(In value) {
+            return static_cast<Out>(std::clamp(static_cast<Intermediate>(value), static_cast<Intermediate>(std::numeric_limits<Out>::min()), static_cast<Intermediate>(std::numeric_limits<Out>::max())));
+        }
+
+        /**
+         * @brief This class is used to abstract an array into a circular buffer
+         * @tparam Type The type of elements stored in the buffer
+         * @tparam Size The maximum size of the circular buffer
+         */
+        template<typename Type, size_t Size>
+        class CircularBuffer {
+          private:
+            std::array<Type, Size> array{}; //!< The internal array holding the circular buffer
+            Type *start{array.begin()}; //!< The start/oldest element of the internal array
+            Type *end{array.begin()}; //!< The end/newest element of the internal array
+            bool empty{true}; //!< This boolean is used to differentiate between the buffer being full or empty
+            Mutex mtx; //!< The mutex ensures that the buffer operations don't overlap
+
+          public:
+            /**
+             * @brief This reads data from this buffer into the specified buffer
+             * @param address The address to write buffer data into
+             * @param maxSize The maximum amount of data to write in units of Type
+             * @param function If this is specified, then this is called rather than memcpy
+             * @return The amount of data written into the input buffer in units of Type
+             */
+            inline size_t Read(Type *address, ssize_t maxSize, void function(Type *, Type *) = {}, ssize_t copyOffset = -1) {
+                std::lock_guard guard(mtx);
+
+                if (empty)
+                    return 0;
+
+                ssize_t size{}, sizeBegin{}, sizeEnd{};
+
+                if (start < end) {
+                    sizeEnd = std::min(end - start, maxSize);
+
+                    size = sizeEnd;
+                } else {
+                    sizeEnd = std::min(array.end() - start, maxSize);
+                    sizeBegin = std::min(end - array.begin(), maxSize - sizeEnd);
+
+                    size = sizeBegin + sizeEnd;
+                }
+
+                if (function && copyOffset) {
+                    auto sourceEnd = start + ((copyOffset != -1) ? copyOffset : sizeEnd);
+
+                    for (auto source = start, destination = address; source < sourceEnd; source++, destination++)
+                        function(source, destination);
+
+                    if (copyOffset != -1) {
+                        std::memcpy(address + copyOffset, start + copyOffset, (sizeEnd - copyOffset) * sizeof(Type));
+                        copyOffset -= sizeEnd;
+                    }
+                } else {
+                    std::memcpy(address, start, sizeEnd * sizeof(Type));
+                }
+
+                address += sizeEnd;
+
+                if (sizeBegin) {
+                    if (function && copyOffset) {
+                        auto sourceEnd = array.begin() + ((copyOffset != -1) ? copyOffset : sizeBegin);
+
+                        for (auto source = array.begin(), destination = address; source < sourceEnd; source++, destination++)
+                            function(source, destination);
+
+                        if (copyOffset != -1)
+                            std::memcpy(array.begin() + copyOffset, address + copyOffset, (sizeBegin - copyOffset) * sizeof(Type));
+                    } else {
+                        std::memcpy(address, array.begin(), sizeBegin * sizeof(Type));
+                    }
+
+                    start = array.begin() + sizeBegin;
+                } else {
+                    start += sizeEnd;
+                }
+
+                if (start == end)
+                    empty = true;
+
+                return static_cast<size_t>(size);
+            }
+
+            /**
+             * @brief This appends data from the specified buffer into this buffer
+             * @param address The address of the buffer
+             * @param size The size of the buffer in units of Type
+             */
+            inline void Append(Type *address, ssize_t size) {
+                std::lock_guard guard(mtx);
+
+                while (size) {
+                    if (start <= end && end != array.end()) {
+                        auto sizeEnd = std::min(array.end() - end, size);
+                        std::memcpy(end, address, sizeEnd * sizeof(Type));
+
+                        address += sizeEnd;
+                        size -= sizeEnd;
+
+                        end += sizeEnd;
+                    } else {
+                        auto sizePreStart = (end == array.end()) ? std::min(start - array.begin(), size) : std::min(start - end, size);
+                        auto sizePostStart = std::min(array.end() - start, size - sizePreStart);
+
+                        if (sizePreStart)
+                            std::memcpy((end == array.end()) ? array.begin() : end, address, sizePreStart * sizeof(Type));
+
+                        if (end == array.end())
+                            end = array.begin() + sizePreStart;
+                        else
+                            end += sizePreStart;
+
+                        address += sizePreStart;
+                        size -= sizePreStart;
+
+                        if (sizePostStart)
+                            std::memcpy(end, address, sizePostStart * sizeof(Type));
+
+                        if (start == array.end())
+                            start = array.begin() + sizePostStart;
+                        else
+                            start += sizePostStart;
+
+                        if (end == array.end())
+                            end = array.begin() + sizePostStart;
+                        else
+                            end += sizePostStart;
+
+                        address += sizePostStart;
+                        size -= sizePostStart;
+                    }
+
+                    empty = false;
+                }
+            }
+
+            /**
+             * @brief This appends data from a vector to the buffer
+             * @param sampleData A reference to a vector containing the data to be appended
+             */
+            inline void Append(const std::vector<Type> &data) {
+                Append(const_cast<Type *>(data.data()), data.size());
+            }
+        };
     }
 }

app/src/main/cpp/skyline/audio/track.cpp

@@ -43,24 +43,21 @@ namespace skyline::audio {
         return bufferIds;
     }
 
-    void AudioTrack::AppendBuffer(const std::vector<i16> &sampleData, u64 tag) {
+    void AudioTrack::AppendBuffer(u64 tag, const i16* address, u64 size) {
         BufferIdentifier identifier;
 
         identifier.released = false;
         identifier.tag = tag;
 
-        if (identifierQueue.empty())
+        if (identifiers.empty())
-            identifier.finalSample = sampleData.size();
+            identifier.finalSample = size;
         else
-            identifier.finalSample = sampleData.size() + identifierQueue.front().finalSample;
+            identifier.finalSample = size + identifiers.front().finalSample;
 
-        bufferLock.lock();
+        std::lock_guard guard(bufferLock);
 
-        identifierQueue.push_front(identifier);
+        identifiers.push_front(identifier);
-        for (const auto &sample : sampleData)
+        samples.Append(const_cast<i16 *>(address), size);
-            sampleQueue.push(sample);
-
-        bufferLock.unlock();
     }
 
     void AudioTrack::CheckReleasedBuffers() {

app/src/main/cpp/skyline/audio/track.h

@@ -22,7 +22,7 @@ namespace skyline::audio {
         const u32 sampleRate; //!< The sample rate of the track
 
       public:
-        std::queue<i16> sampleQueue; //!< Queue of all appended buffer data
+        CircularBuffer<i16, constant::SampleRate * constant::ChannelCount * 10> samples; //!< A vector of all appended audio samples
         Mutex bufferLock; //!< This mutex ensures that appending to buffers doesn't overlap
 
         AudioOutState playbackState{AudioOutState::Stopped}; //!< The current state of playback
@@ -63,10 +63,20 @@ namespace skyline::audio {
 
         /**
          * @brief Appends audio samples to the output buffer
-         * @param sampleData Reference to a vector containing I16 format pcm data
          * @param tag The tag of the buffer
+         * @param address The address of the audio buffer
+         * @param size The size of the audio buffer in i16 units
          */
-        void AppendBuffer(const std::vector<i16> &sampleData, u64 tag);
+        void AppendBuffer(u64 tag, const i16* address, u64 size);
+
+        /**
+         * @brief Appends audio samples to the output buffer
+         * @param tag The tag of the buffer
+         * @param sampleData A reference to a vector containing I16 format PCM data
+         */
+        void AppendBuffer(u64 tag, const std::vector<i16> &sampleData = {}) {
+            AppendBuffer(tag, sampleData.data(), sampleData.size());
+        }
 
         /**
          * @brief Checks if any buffers have been released and calls the appropriate callback for them

app/src/main/cpp/skyline/services/audio/IAudioOut.cpp

@@ -47,10 +47,15 @@ namespace skyline::service::audio {
 
         state.logger->Debug("IAudioOut: Appending buffer with address: 0x{:X}, size: 0x{:X}", data.sampleBufferPtr, data.sampleSize);
 
+        if(sampleRate != constant::SampleRate) {
             tmpSampleBuffer.resize(data.sampleSize / sizeof(i16));
             state.process->ReadMemory(tmpSampleBuffer.data(), data.sampleBufferPtr, data.sampleSize);
             resampler.ResampleBuffer(tmpSampleBuffer, static_cast<double>(sampleRate) / constant::SampleRate, channelCount);
-        track->AppendBuffer(tmpSampleBuffer, tag);
+
+            track->AppendBuffer(tag, tmpSampleBuffer);
+        } else {
+            track->AppendBuffer(tag, state.process->GetPointer<i16>(data.sampleBufferPtr), data.sampleSize);
+        }
     }
 
     void IAudioOut::RegisterBufferEvent(type::KSession &session, ipc::IpcRequest &request, ipc::IpcResponse &response) {

app/src/main/cpp/skyline/services/audio/IAudioRenderer/IAudioRenderer.cpp

@@ -5,8 +5,8 @@
 #include "IAudioRenderer.h"
 
 namespace skyline::service::audio::IAudioRenderer {
-    IAudioRenderer::IAudioRenderer(const DeviceState &state, ServiceManager &manager, AudioRendererParams &params)
+    IAudioRenderer::IAudioRenderer(const DeviceState &state, ServiceManager &manager, AudioRendererParameters &parameters)
-        : releaseEvent(std::make_shared<type::KEvent>(state)), rendererParams(params), memoryPoolCount(params.effectCount + params.voiceCount * 4), samplesPerBuffer(state.settings->GetInt("audren_buffer_size")), BaseService(state, manager, Service::audio_IAudioRenderer, "audio:IAudioRenderer", {
+        : releaseEvent(std::make_shared<type::KEvent>(state)), parameters(parameters), BaseService(state, manager, Service::audio_IAudioRenderer, "audio:IAudioRenderer", {
         {0x0, SFUNC(IAudioRenderer::GetSampleRate)},
         {0x1, SFUNC(IAudioRenderer::GetSampleCount)},
         {0x2, SFUNC(IAudioRenderer::GetMixBufferCount)},
@@ -16,17 +16,17 @@ namespace skyline::service::audio::IAudioRenderer {
         {0x6, SFUNC(IAudioRenderer::Stop)},
         {0x7, SFUNC(IAudioRenderer::QuerySystemEvent)},
     }) {
-        track = state.audio->OpenTrack(constant::ChannelCount, params.sampleRate, [this]() { this->releaseEvent->Signal(); });
+        track = state.audio->OpenTrack(constant::ChannelCount, parameters.sampleRate, [this]() { releaseEvent->Signal(); });
         track->Start();
 
-        memoryPools.resize(memoryPoolCount);
+        memoryPools.resize(parameters.effectCount + parameters.voiceCount * 4);
-        effects.resize(rendererParams.effectCount);
+        effects.resize(parameters.effectCount);
-        voices.resize(rendererParams.voiceCount, Voice(state));
+        voices.resize(parameters.voiceCount, Voice(state));
 
         // Fill track with empty samples that we will triple buffer
-        track->AppendBuffer(std::vector<i16>(), 0);
+        track->AppendBuffer(0);
-        track->AppendBuffer(std::vector<i16>(), 1);
+        track->AppendBuffer(1);
-        track->AppendBuffer(std::vector<i16>(), 2);
+        track->AppendBuffer(2);
     }
 
     IAudioRenderer::~IAudioRenderer() {
@@ -34,15 +34,15 @@ namespace skyline::service::audio::IAudioRenderer {
     }
 
     void IAudioRenderer::GetSampleRate(type::KSession &session, ipc::IpcRequest &request, ipc::IpcResponse &response) {
-        response.Push<u32>(rendererParams.sampleRate);
+        response.Push<u32>(parameters.sampleRate);
     }
 
     void IAudioRenderer::GetSampleCount(type::KSession &session, ipc::IpcRequest &request, ipc::IpcResponse &response) {
-        response.Push<u32>(rendererParams.sampleCount);
+        response.Push<u32>(parameters.sampleCount);
     }
 
     void IAudioRenderer::GetMixBufferCount(type::KSession &session, ipc::IpcRequest &request, ipc::IpcResponse &response) {
-        response.Push<u32>(rendererParams.subMixCount);
+        response.Push<u32>(parameters.subMixCount);
     }
 
     void IAudioRenderer::GetState(type::KSession &session, ipc::IpcRequest &request, ipc::IpcResponse &response) {
@@ -57,6 +57,7 @@ namespace skyline::service::audio::IAudioRenderer {
         inputAddress += sizeof(UpdateDataHeader);
         inputAddress += inputHeader.behaviorSize; // Unused
 
+        auto memoryPoolCount = memoryPools.size();
         std::vector<MemoryPoolIn> memoryPoolsIn(memoryPoolCount);
         state.process->ReadMemory(memoryPoolsIn.data(), inputAddress, memoryPoolCount * sizeof(MemoryPoolIn));
         inputAddress += inputHeader.memoryPoolSize;
@@ -65,15 +66,15 @@ namespace skyline::service::audio::IAudioRenderer {
             memoryPools[i].ProcessInput(memoryPoolsIn[i]);
 
         inputAddress += inputHeader.voiceResourceSize;
-        std::vector<VoiceIn> voicesIn(rendererParams.voiceCount);
+        std::vector<VoiceIn> voicesIn(parameters.voiceCount);
-        state.process->ReadMemory(voicesIn.data(), inputAddress, rendererParams.voiceCount * sizeof(VoiceIn));
+        state.process->ReadMemory(voicesIn.data(), inputAddress, parameters.voiceCount * sizeof(VoiceIn));
         inputAddress += inputHeader.voiceSize;
 
         for (auto i = 0; i < voicesIn.size(); i++)
             voices[i].ProcessInput(voicesIn[i]);
 
-        std::vector<EffectIn> effectsIn(rendererParams.effectCount);
+        std::vector<EffectIn> effectsIn(parameters.effectCount);
-        state.process->ReadMemory(effectsIn.data(), inputAddress, rendererParams.effectCount * sizeof(EffectIn));
+        state.process->ReadMemory(effectsIn.data(), inputAddress, parameters.effectCount * sizeof(EffectIn));
 
         for (auto i = 0; i < effectsIn.size(); i++)
             effects[i].ProcessInput(effectsIn[i]);
@@ -83,10 +84,10 @@ namespace skyline::service::audio::IAudioRenderer {
         UpdateDataHeader outputHeader{
             .revision = constant::RevMagic,
             .behaviorSize = 0xb0,
-            .memoryPoolSize = (rendererParams.effectCount + rendererParams.voiceCount * 4) * static_cast<u32>(sizeof(MemoryPoolOut)),
+            .memoryPoolSize = (parameters.effectCount + parameters.voiceCount * 4) * static_cast<u32>(sizeof(MemoryPoolOut)),
-            .voiceSize = rendererParams.voiceCount * static_cast<u32>(sizeof(VoiceOut)),
+            .voiceSize = parameters.voiceCount * static_cast<u32>(sizeof(VoiceOut)),
-            .effectSize = rendererParams.effectCount * static_cast<u32>(sizeof(EffectOut)),
+            .effectSize = parameters.effectCount * static_cast<u32>(sizeof(EffectOut)),
-            .sinkSize = rendererParams.sinkCount * 0x20,
+            .sinkSize = parameters.sinkCount * 0x20,
             .performanceManagerSize = 0x10,
             .elapsedFrameCountInfoSize = 0x0
         };
@@ -129,38 +130,37 @@ namespace skyline::service::audio::IAudioRenderer {
 
         for (auto &tag : released) {
             MixFinalBuffer();
-            track->AppendBuffer(sampleBuffer, tag);
+            track->AppendBuffer(tag, sampleBuffer.data(), sampleBuffer.size());
         }
     }
 
     void IAudioRenderer::MixFinalBuffer() {
-        int setIndex = 0;
+        u32 writtenSamples = 0;
-        sampleBuffer.resize(static_cast<size_t>(samplesPerBuffer * constant::ChannelCount));
 
         for (auto &voice : voices) {
             if (!voice.Playable())
                 continue;
 
-            int bufferOffset = 0;
+            u32 bufferOffset{};
-            int pendingSamples = samplesPerBuffer;
+            u32 pendingSamples = constant::MixBufferSize;
 
             while (pendingSamples > 0) {
-                int voiceBufferSize = 0;
+                u32 voiceBufferOffset{};
-                int voiceBufferOffset = 0;
+                u32 voiceBufferSize{};
-                std::vector<i16> &voiceSamples = voice.GetBufferData(pendingSamples, voiceBufferOffset, voiceBufferSize);
+                auto &voiceSamples = voice.GetBufferData(pendingSamples, voiceBufferOffset, voiceBufferSize);
 
                 if (voiceBufferSize == 0)
                     break;
 
                 pendingSamples -= voiceBufferSize / constant::ChannelCount;
 
-                for (int i = voiceBufferOffset; i < voiceBufferOffset + voiceBufferSize; i++) {
+                for (auto index = voiceBufferOffset; index < voiceBufferOffset + voiceBufferSize; index++) {
-                    if (setIndex == bufferOffset) {
+                    if (writtenSamples == bufferOffset) {
-                        sampleBuffer[bufferOffset] = static_cast<i16>(std::clamp(static_cast<int>(static_cast<float>(voiceSamples[i]) * voice.volume), static_cast<int>(std::numeric_limits<i16>::min()), static_cast<int>(std::numeric_limits<i16>::max())));
+                        sampleBuffer[bufferOffset] = skyline::audio::Saturate<i16, i32>(voiceSamples[index] * voice.volume);
 
-                        setIndex++;
+                        writtenSamples++;
                     } else {
-                        sampleBuffer[bufferOffset] += static_cast<i16>(std::clamp(static_cast<int>(sampleBuffer[voiceSamples[i]]) + static_cast<int>(static_cast<float>(voiceSamples[i]) * voice.volume), static_cast<int>(std::numeric_limits<i16>::min()), static_cast<int>(std::numeric_limits<i16>::max())));
+                        sampleBuffer[bufferOffset] = skyline::audio::Saturate<i16, i32>(sampleBuffer[bufferOffset] + (voiceSamples[index] * voice.volume));
                     }
 
                     bufferOffset++;

app/src/main/cpp/skyline/services/audio/IAudioRenderer/IAudioRenderer.h

@@ -21,7 +21,7 @@ namespace skyline {
         /**
          * @brief The parameters used to configure an IAudioRenderer
          */
-        struct AudioRendererParams {
+        struct AudioRendererParameters {
             u32 sampleRate; //!< The sample rate to use for the renderer
             u32 sampleCount; //!< The buffer sample count
             u32 mixBufferCount; //!< The amount of mix buffers to use
@@ -36,7 +36,7 @@ namespace skyline {
             u32 _unk0_;
             u32 revision; //!< The revision of audren to use
         };
-        static_assert(sizeof(AudioRendererParams) == 0x34);
+        static_assert(sizeof(AudioRendererParameters) == 0x34);
 
         /**
          * @brief Header containing information about the software side audren implementation
@@ -63,21 +63,19 @@ namespace skyline {
         */
         class IAudioRenderer : public BaseService {
           private:
-            AudioRendererParams rendererParams; //!< The parameters to use for the renderer
+            AudioRendererParameters parameters; //!< The parameters to use for the renderer
             RevisionInfo revisionInfo{}; //!< Stores info about supported features for the audren revision used
             std::shared_ptr<skyline::audio::AudioTrack> track; //!< The audio track associated with the audio renderer
             std::shared_ptr<type::KEvent> releaseEvent; //!< The KEvent that is signalled when a buffer has been released
             std::vector<MemoryPool> memoryPools; //!< An vector of all memory pools that the guest may need
             std::vector<Effect> effects; //!< An vector of all effects that the guest may need
             std::vector<Voice> voices; //!< An vector of all voices that the guest may need
-            std::vector<i16> sampleBuffer; //!< The final output data that is appended to the stream
+            std::array<i16, constant::MixBufferSize * constant::ChannelCount> sampleBuffer; //!< The final output data that is appended to the stream
-
             skyline::audio::AudioOutState playbackState{skyline::audio::AudioOutState::Stopped}; //!< The current state of playback
-            const size_t memoryPoolCount; //!< The amount of memory pools the guest may need
-            const int samplesPerBuffer; //!< The amount of samples each appended buffer should contain
 
             /**
              * @brief Obtains new sample data from voices and mixes it together into the sample buffer
+             * @return The amount of samples present in the buffer
              */
             void MixFinalBuffer();
 
@@ -88,9 +86,9 @@ namespace skyline {
 
           public:
             /**
-             * @param params The parameters to use for rendering
+             * @param parameters The parameters to use for rendering
              */
-            IAudioRenderer(const DeviceState &state, ServiceManager &manager, AudioRendererParams &params);
+            IAudioRenderer(const DeviceState &state, ServiceManager &manager, AudioRendererParameters &parameters);
 
             /**
              * @brief Closes the audio track