7 files changed, 673 insertions, 0 deletions

diff --git a/src/audio_core/adsp/apps/opus/opus_decode_object.cpp b/src/audio_core/adsp/apps/opus/opus_decode_object.cpp
new file mode 100644
index 000000000..2c16d3769
--- /dev/null
+++ b/src/audio_core/adsp/apps/opus/opus_decode_object.cpp
@@ -0,0 +1,107 @@
+// SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project

+// SPDX-License-Identifier: GPL-2.0-or-later

+

+#include "audio_core/adsp/apps/opus/opus_decode_object.h"

+#include "common/assert.h"

+

+namespace AudioCore::ADSP::OpusDecoder {

+namespace {

+bool IsValidChannelCount(u32 channel_count) {

+    return channel_count == 1 || channel_count == 2;

+}

+} // namespace

+

+u32 OpusDecodeObject::GetWorkBufferSize(u32 channel_count) {

+    if (!IsValidChannelCount(channel_count)) {

+        return 0;

+    }

+    return static_cast<u32>(sizeof(OpusDecodeObject)) + opus_decoder_get_size(channel_count);

+}

+

+OpusDecodeObject& OpusDecodeObject::Initialize(u64 buffer, u64 buffer2) {

+    auto* new_decoder = reinterpret_cast<OpusDecodeObject*>(buffer);

+    auto* comparison = reinterpret_cast<OpusDecodeObject*>(buffer2);

+

+    if (new_decoder->magic == DecodeObjectMagic) {

+        if (!new_decoder->initialized ||

+            (new_decoder->initialized && new_decoder->self == comparison)) {

+            new_decoder->state_valid = true;

+        }

+    } else {

+        new_decoder->initialized = false;

+        new_decoder->state_valid = true;

+    }

+    return *new_decoder;

+}

+

+s32 OpusDecodeObject::InitializeDecoder(u32 sample_rate, u32 channel_count) {

+    if (!state_valid) {

+        return OPUS_INVALID_STATE;

+    }

+

+    if (initialized) {

+        return OPUS_OK;

+    }

+

+    // Unfortunately libopus does not expose the OpusDecoder struct publicly, so we can't include

+    // it in this class. Nintendo does not allocate memory, which is why we have a workbuffer

+    // provided.

+    // We could use _create and have libopus allocate it for us, but then we have to separately

+    // track which decoder is being used between this and multistream in order to call the correct

+    // destroy from the host side.

+    // This is a bit cringe, but is safe as these objects are only ever initialized inside the given

+    // workbuffer, and GetWorkBufferSize will guarantee there's enough space to follow.

+    decoder = (LibOpusDecoder*)(this + 1);

+    s32 ret = opus_decoder_init(decoder, sample_rate, channel_count);

+    if (ret == OPUS_OK) {

+        magic = DecodeObjectMagic;

+        initialized = true;

+        state_valid = true;

+        self = this;

+        final_range = 0;

+    }

+    return ret;

+}

+

+s32 OpusDecodeObject::Shutdown() {

+    if (!state_valid) {

+        return OPUS_INVALID_STATE;

+    }

+

+    if (initialized) {

+        magic = 0x0;

+        initialized = false;

+        state_valid = false;

+        self = nullptr;

+        final_range = 0;

+        decoder = nullptr;

+    }

+    return OPUS_OK;

+}

+

+s32 OpusDecodeObject::ResetDecoder() {

+    return opus_decoder_ctl(decoder, OPUS_RESET_STATE);

+}

+

+s32 OpusDecodeObject::Decode(u32& out_sample_count, u64 output_data, u64 output_data_size,

+                             u64 input_data, u64 input_data_size) {

+    ASSERT(initialized);

+    out_sample_count = 0;

+

+    if (!state_valid) {

+        return OPUS_INVALID_STATE;

+    }

+

+    auto ret_code_or_samples = opus_decode(

+        decoder, reinterpret_cast<const u8*>(input_data), static_cast<opus_int32>(input_data_size),

+        reinterpret_cast<opus_int16*>(output_data), static_cast<opus_int32>(output_data_size), 0);

+

+    if (ret_code_or_samples < OPUS_OK) {

+        return ret_code_or_samples;

+    }

+

+    out_sample_count = ret_code_or_samples;

+    return opus_decoder_ctl(decoder, OPUS_GET_FINAL_RANGE_REQUEST, &final_range);

+}

+

+} // namespace AudioCore::ADSP::OpusDecoder

diff --git a/src/audio_core/adsp/apps/opus/opus_decode_object.h b/src/audio_core/adsp/apps/opus/opus_decode_object.h
new file mode 100644
index 000000000..6425f987c
--- /dev/null
+++ b/src/audio_core/adsp/apps/opus/opus_decode_object.h
@@ -0,0 +1,38 @@
+// SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <opus.h>
+
+#include "common/common_types.h"
+
+namespace AudioCore::ADSP::OpusDecoder {
+using LibOpusDecoder = ::OpusDecoder;
+static constexpr u32 DecodeObjectMagic = 0xDEADBEEF;
+
+class OpusDecodeObject {
+public:
+    static u32 GetWorkBufferSize(u32 channel_count);
+    static OpusDecodeObject& Initialize(u64 buffer, u64 buffer2);
+
+    s32 InitializeDecoder(u32 sample_rate, u32 channel_count);
+    s32 Shutdown();
+    s32 ResetDecoder();
+    s32 Decode(u32& out_sample_count, u64 output_data, u64 output_data_size, u64 input_data,
+               u64 input_data_size);
+    u32 GetFinalRange() const noexcept {
+        return final_range;
+    }
+
+private:
+    u32 magic;
+    bool initialized;
+    bool state_valid;
+    OpusDecodeObject* self;
+    u32 final_range;
+    LibOpusDecoder* decoder;
+};
+static_assert(std::is_trivially_constructible_v<OpusDecodeObject>);
+
+} // namespace AudioCore::ADSP::OpusDecoder
diff --git a/src/audio_core/adsp/apps/opus/opus_decoder.cpp b/src/audio_core/adsp/apps/opus/opus_decoder.cpp
new file mode 100644
index 000000000..2084de128
--- /dev/null
+++ b/src/audio_core/adsp/apps/opus/opus_decoder.cpp
@@ -0,0 +1,269 @@
+// SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <array>
+#include <chrono>
+
+#include "audio_core/adsp/apps/opus/opus_decode_object.h"
+#include "audio_core/adsp/apps/opus/opus_multistream_decode_object.h"
+#include "audio_core/adsp/apps/opus/shared_memory.h"
+#include "audio_core/audio_core.h"
+#include "audio_core/common/common.h"
+#include "common/logging/log.h"
+#include "common/microprofile.h"
+#include "common/thread.h"
+#include "core/core.h"
+#include "core/core_timing.h"
+
+MICROPROFILE_DEFINE(OpusDecoder, "Audio", "DSP_OpusDecoder", MP_RGB(60, 19, 97));
+
+namespace AudioCore::ADSP::OpusDecoder {
+
+namespace {
+constexpr size_t OpusStreamCountMax = 255;
+
+bool IsValidChannelCount(u32 channel_count) {
+    return channel_count == 1 || channel_count == 2;
+}
+
+bool IsValidMultiStreamChannelCount(u32 channel_count) {
+    return channel_count <= OpusStreamCountMax;
+}
+
+bool IsValidMultiStreamStreamCounts(s32 total_stream_count, s32 sterero_stream_count) {
+    return IsValidMultiStreamChannelCount(total_stream_count) && total_stream_count > 0 &&
+           sterero_stream_count > 0 && sterero_stream_count <= total_stream_count;
+}
+} // namespace
+
+OpusDecoder::OpusDecoder(Core::System& system_) : system{system_} {
+    init_thread = std::jthread([this](std::stop_token stop_token) { Init(stop_token); });
+}
+
+OpusDecoder::~OpusDecoder() {
+    if (!running) {
+        init_thread.request_stop();
+        return;
+    }
+
+    // Shutdown the thread
+    Send(Direction::DSP, Message::Shutdown);
+    auto msg = Receive(Direction::Host);
+    ASSERT_MSG(msg == Message::ShutdownOK, "Expected Opus shutdown code {}, got {}",
+               Message::ShutdownOK, msg);
+    main_thread.request_stop();
+    main_thread.join();
+    running = false;
+}
+
+void OpusDecoder::Send(Direction dir, u32 message) {
+    mailbox.Send(dir, std::move(message));
+}
+
+u32 OpusDecoder::Receive(Direction dir, std::stop_token stop_token) {
+    return mailbox.Receive(dir, stop_token);
+}
+
+void OpusDecoder::Init(std::stop_token stop_token) {
+    Common::SetCurrentThreadName("DSP_OpusDecoder_Init");
+
+    if (Receive(Direction::DSP, stop_token) != Message::Start) {
+        LOG_ERROR(Service_Audio,
+                  "DSP OpusDecoder failed to receive Start message. Opus initialization failed.");
+        return;
+    }
+    main_thread = std::jthread([this](std::stop_token st) { Main(st); });
+    running = true;
+    Send(Direction::Host, Message::StartOK);
+}
+
+void OpusDecoder::Main(std::stop_token stop_token) {
+    Common::SetCurrentThreadName("DSP_OpusDecoder_Main");
+
+    while (!stop_token.stop_requested()) {
+        auto msg = Receive(Direction::DSP, stop_token);
+        switch (msg) {
+        case Shutdown:
+            Send(Direction::Host, Message::ShutdownOK);
+            return;
+
+        case GetWorkBufferSize: {
+            auto channel_count = static_cast<s32>(shared_memory->host_send_data[0]);
+
+            ASSERT(IsValidChannelCount(channel_count));
+
+            shared_memory->dsp_return_data[0] = OpusDecodeObject::GetWorkBufferSize(channel_count);
+            Send(Direction::Host, Message::GetWorkBufferSizeOK);
+        } break;
+
+        case InitializeDecodeObject: {
+            auto buffer = shared_memory->host_send_data[0];
+            auto buffer_size = shared_memory->host_send_data[1];
+            auto sample_rate = static_cast<s32>(shared_memory->host_send_data[2]);
+            auto channel_count = static_cast<s32>(shared_memory->host_send_data[3]);
+
+            ASSERT(sample_rate >= 0);
+            ASSERT(IsValidChannelCount(channel_count));
+            ASSERT(buffer_size >= OpusDecodeObject::GetWorkBufferSize(channel_count));
+
+            auto& decoder_object = OpusDecodeObject::Initialize(buffer, buffer);
+            shared_memory->dsp_return_data[0] =
+                decoder_object.InitializeDecoder(sample_rate, channel_count);
+
+            Send(Direction::Host, Message::InitializeDecodeObjectOK);
+        } break;
+
+        case ShutdownDecodeObject: {
+            auto buffer = shared_memory->host_send_data[0];
+            [[maybe_unused]] auto buffer_size = shared_memory->host_send_data[1];
+
+            auto& decoder_object = OpusDecodeObject::Initialize(buffer, buffer);
+            shared_memory->dsp_return_data[0] = decoder_object.Shutdown();
+
+            Send(Direction::Host, Message::ShutdownDecodeObjectOK);
+        } break;
+
+        case DecodeInterleaved: {
+            auto start_time = system.CoreTiming().GetGlobalTimeUs();
+
+            auto buffer = shared_memory->host_send_data[0];
+            auto input_data = shared_memory->host_send_data[1];
+            auto input_data_size = shared_memory->host_send_data[2];
+            auto output_data = shared_memory->host_send_data[3];
+            auto output_data_size = shared_memory->host_send_data[4];
+            auto final_range = static_cast<u32>(shared_memory->host_send_data[5]);
+            auto reset_requested = shared_memory->host_send_data[6];
+
+            u32 decoded_samples{0};
+
+            auto& decoder_object = OpusDecodeObject::Initialize(buffer, buffer);
+            s32 error_code{OPUS_OK};
+            if (reset_requested) {
+                error_code = decoder_object.ResetDecoder();
+            }
+
+            if (error_code == OPUS_OK) {
+                error_code = decoder_object.Decode(decoded_samples, output_data, output_data_size,
+                                                   input_data, input_data_size);
+            }
+
+            if (error_code == OPUS_OK) {
+                if (final_range && decoder_object.GetFinalRange() != final_range) {
+                    error_code = OPUS_INVALID_PACKET;
+                }
+            }
+
+            auto end_time = system.CoreTiming().GetGlobalTimeUs();
+            shared_memory->dsp_return_data[0] = error_code;
+            shared_memory->dsp_return_data[1] = decoded_samples;
+            shared_memory->dsp_return_data[2] = (end_time - start_time).count();
+
+            Send(Direction::Host, Message::DecodeInterleavedOK);
+        } break;
+
+        case MapMemory: {
+            [[maybe_unused]] auto buffer = shared_memory->host_send_data[0];
+            [[maybe_unused]] auto buffer_size = shared_memory->host_send_data[1];
+            Send(Direction::Host, Message::MapMemoryOK);
+        } break;
+
+        case UnmapMemory: {
+            [[maybe_unused]] auto buffer = shared_memory->host_send_data[0];
+            [[maybe_unused]] auto buffer_size = shared_memory->host_send_data[1];
+            Send(Direction::Host, Message::UnmapMemoryOK);
+        } break;
+
+        case GetWorkBufferSizeForMultiStream: {
+            auto total_stream_count = static_cast<s32>(shared_memory->host_send_data[0]);
+            auto stereo_stream_count = static_cast<s32>(shared_memory->host_send_data[1]);
+
+            ASSERT(IsValidMultiStreamStreamCounts(total_stream_count, stereo_stream_count));
+
+            shared_memory->dsp_return_data[0] = OpusMultiStreamDecodeObject::GetWorkBufferSize(
+                total_stream_count, stereo_stream_count);
+            Send(Direction::Host, Message::GetWorkBufferSizeForMultiStreamOK);
+        } break;
+
+        case InitializeMultiStreamDecodeObject: {
+            auto buffer = shared_memory->host_send_data[0];
+            auto buffer_size = shared_memory->host_send_data[1];
+            auto sample_rate = static_cast<s32>(shared_memory->host_send_data[2]);
+            auto channel_count = static_cast<s32>(shared_memory->host_send_data[3]);
+            auto total_stream_count = static_cast<s32>(shared_memory->host_send_data[4]);
+            auto stereo_stream_count = static_cast<s32>(shared_memory->host_send_data[5]);
+            // Nintendo seem to have a bug here, they try to use &host_send_data[6] for the channel
+            // mappings, but [6] is never set, and there is not enough room in the argument data for
+            // more than 40 channels, when 255 are possible.
+            // It also means the mapping values are undefined, though likely always 0,
+            // and the mappings given by the game are ignored. The mappings are copied to this
+            // dedicated buffer host side, so let's do as intended.
+            auto mappings = shared_memory->channel_mapping.data();
+
+            ASSERT(IsValidMultiStreamStreamCounts(total_stream_count, stereo_stream_count));
+            ASSERT(sample_rate >= 0);
+            ASSERT(buffer_size >= OpusMultiStreamDecodeObject::GetWorkBufferSize(
+                                      total_stream_count, stereo_stream_count));
+
+            auto& decoder_object = OpusMultiStreamDecodeObject::Initialize(buffer, buffer);
+            shared_memory->dsp_return_data[0] = decoder_object.InitializeDecoder(
+                sample_rate, total_stream_count, channel_count, stereo_stream_count, mappings);
+
+            Send(Direction::Host, Message::InitializeMultiStreamDecodeObjectOK);
+        } break;
+
+        case ShutdownMultiStreamDecodeObject: {
+            auto buffer = shared_memory->host_send_data[0];
+            [[maybe_unused]] auto buffer_size = shared_memory->host_send_data[1];
+
+            auto& decoder_object = OpusMultiStreamDecodeObject::Initialize(buffer, buffer);
+            shared_memory->dsp_return_data[0] = decoder_object.Shutdown();
+
+            Send(Direction::Host, Message::ShutdownMultiStreamDecodeObjectOK);
+        } break;
+
+        case DecodeInterleavedForMultiStream: {
+            auto start_time = system.CoreTiming().GetGlobalTimeUs();
+
+            auto buffer = shared_memory->host_send_data[0];
+            auto input_data = shared_memory->host_send_data[1];
+            auto input_data_size = shared_memory->host_send_data[2];
+            auto output_data = shared_memory->host_send_data[3];
+            auto output_data_size = shared_memory->host_send_data[4];
+            auto final_range = static_cast<u32>(shared_memory->host_send_data[5]);
+            auto reset_requested = shared_memory->host_send_data[6];
+
+            u32 decoded_samples{0};
+
+            auto& decoder_object = OpusMultiStreamDecodeObject::Initialize(buffer, buffer);
+            s32 error_code{OPUS_OK};
+            if (reset_requested) {
+                error_code = decoder_object.ResetDecoder();
+            }
+
+            if (error_code == OPUS_OK) {
+                error_code = decoder_object.Decode(decoded_samples, output_data, output_data_size,
+                                                   input_data, input_data_size);
+            }
+
+            if (error_code == OPUS_OK) {
+                if (final_range && decoder_object.GetFinalRange() != final_range) {
+                    error_code = OPUS_INVALID_PACKET;
+                }
+            }
+
+            auto end_time = system.CoreTiming().GetGlobalTimeUs();
+            shared_memory->dsp_return_data[0] = error_code;
+            shared_memory->dsp_return_data[1] = decoded_samples;
+            shared_memory->dsp_return_data[2] = (end_time - start_time).count();
+
+            Send(Direction::Host, Message::DecodeInterleavedForMultiStreamOK);
+        } break;
+
+        default:
+            LOG_ERROR(Service_Audio, "Invalid OpusDecoder command {}", msg);
+            continue;
+        }
+    }
+}
+
+} // namespace AudioCore::ADSP::OpusDecoder
diff --git a/src/audio_core/adsp/apps/opus/opus_decoder.h b/src/audio_core/adsp/apps/opus/opus_decoder.h
new file mode 100644
index 000000000..fcb89bb40
--- /dev/null
+++ b/src/audio_core/adsp/apps/opus/opus_decoder.h
@@ -0,0 +1,92 @@
+// SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <memory>
+#include <thread>
+
+#include "audio_core/adsp/apps/opus/shared_memory.h"
+#include "audio_core/adsp/mailbox.h"
+#include "common/common_types.h"
+
+namespace Core {
+class System;
+} // namespace Core
+
+namespace AudioCore::ADSP::OpusDecoder {
+
+enum Message : u32 {
+    Invalid = 0,
+    Start = 1,
+    Shutdown = 2,
+    StartOK = 11,
+    ShutdownOK = 12,
+    GetWorkBufferSize = 21,
+    InitializeDecodeObject = 22,
+    ShutdownDecodeObject = 23,
+    DecodeInterleaved = 24,
+    MapMemory = 25,
+    UnmapMemory = 26,
+    GetWorkBufferSizeForMultiStream = 27,
+    InitializeMultiStreamDecodeObject = 28,
+    ShutdownMultiStreamDecodeObject = 29,
+    DecodeInterleavedForMultiStream = 30,
+
+    GetWorkBufferSizeOK = 41,
+    InitializeDecodeObjectOK = 42,
+    ShutdownDecodeObjectOK = 43,
+    DecodeInterleavedOK = 44,
+    MapMemoryOK = 45,
+    UnmapMemoryOK = 46,
+    GetWorkBufferSizeForMultiStreamOK = 47,
+    InitializeMultiStreamDecodeObjectOK = 48,
+    ShutdownMultiStreamDecodeObjectOK = 49,
+    DecodeInterleavedForMultiStreamOK = 50,
+};
+
+/**
+ * The AudioRenderer application running on the ADSP.
+ */
+class OpusDecoder {
+public:
+    explicit OpusDecoder(Core::System& system);
+    ~OpusDecoder();
+
+    bool IsRunning() const noexcept {
+        return running;
+    }
+
+    void Send(Direction dir, u32 message);
+    u32 Receive(Direction dir, std::stop_token stop_token = {});
+
+    void SetSharedMemory(SharedMemory& shared_memory_) {
+        shared_memory = &shared_memory_;
+    }
+
+private:
+    /**
+     * Initializing thread, launched at audio_core boot to avoid blocking the main emu boot thread.
+     */
+    void Init(std::stop_token stop_token);
+    /**
+     * Main OpusDecoder thread, responsible for processing the incoming Opus packets.
+     */
+    void Main(std::stop_token stop_token);
+
+    /// Core system
+    Core::System& system;
+    /// Mailbox to communicate messages with the host, drives the main thread
+    Mailbox mailbox;
+    /// Init thread
+    std::jthread init_thread{};
+    /// Main thread
+    std::jthread main_thread{};
+    /// The current state
+    bool running{};
+    /// Structure shared with the host, input data set by the host before sending a mailbox message,
+    /// and the responses are written back by the OpusDecoder.
+    SharedMemory* shared_memory{};
+};
+
+} // namespace AudioCore::ADSP::OpusDecoder
diff --git a/src/audio_core/adsp/apps/opus/opus_multistream_decode_object.cpp b/src/audio_core/adsp/apps/opus/opus_multistream_decode_object.cpp
new file mode 100644
index 000000000..f6d362e68
--- /dev/null
+++ b/src/audio_core/adsp/apps/opus/opus_multistream_decode_object.cpp
@@ -0,0 +1,111 @@
+// SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project

+// SPDX-License-Identifier: GPL-2.0-or-later

+

+#include "audio_core/adsp/apps/opus/opus_multistream_decode_object.h"

+#include "common/assert.h"

+

+namespace AudioCore::ADSP::OpusDecoder {

+

+namespace {

+bool IsValidChannelCount(u32 channel_count) {

+    return channel_count == 1 || channel_count == 2;

+}

+

+bool IsValidStreamCounts(u32 total_stream_count, u32 stereo_stream_count) {

+    return total_stream_count > 0 && stereo_stream_count > 0 &&

+           stereo_stream_count <= total_stream_count && IsValidChannelCount(total_stream_count);

+}

+} // namespace

+

+u32 OpusMultiStreamDecodeObject::GetWorkBufferSize(u32 total_stream_count,

+                                                   u32 stereo_stream_count) {

+    if (IsValidStreamCounts(total_stream_count, stereo_stream_count)) {

+        return static_cast<u32>(sizeof(OpusMultiStreamDecodeObject)) +

+               opus_multistream_decoder_get_size(total_stream_count, stereo_stream_count);

+    }

+    return 0;

+}

+

+OpusMultiStreamDecodeObject& OpusMultiStreamDecodeObject::Initialize(u64 buffer, u64 buffer2) {

+    auto* new_decoder = reinterpret_cast<OpusMultiStreamDecodeObject*>(buffer);

+    auto* comparison = reinterpret_cast<OpusMultiStreamDecodeObject*>(buffer2);

+

+    if (new_decoder->magic == DecodeMultiStreamObjectMagic) {

+        if (!new_decoder->initialized ||

+            (new_decoder->initialized && new_decoder->self == comparison)) {

+            new_decoder->state_valid = true;

+        }

+    } else {

+        new_decoder->initialized = false;

+        new_decoder->state_valid = true;

+    }

+    return *new_decoder;

+}

+

+s32 OpusMultiStreamDecodeObject::InitializeDecoder(u32 sample_rate, u32 total_stream_count,

+                                                   u32 channel_count, u32 stereo_stream_count,

+                                                   u8* mappings) {

+    if (!state_valid) {

+        return OPUS_INVALID_STATE;

+    }

+

+    if (initialized) {

+        return OPUS_OK;

+    }

+

+    // See OpusDecodeObject::InitializeDecoder for an explanation of this

+    decoder = (LibOpusMSDecoder*)(this + 1);

+    s32 ret = opus_multistream_decoder_init(decoder, sample_rate, channel_count, total_stream_count,

+                                            stereo_stream_count, mappings);

+    if (ret == OPUS_OK) {

+        magic = DecodeMultiStreamObjectMagic;

+        initialized = true;

+        state_valid = true;

+        self = this;

+        final_range = 0;

+    }

+    return ret;

+}

+

+s32 OpusMultiStreamDecodeObject::Shutdown() {

+    if (!state_valid) {

+        return OPUS_INVALID_STATE;

+    }

+

+    if (initialized) {

+        magic = 0x0;

+        initialized = false;

+        state_valid = false;

+        self = nullptr;

+        final_range = 0;

+        decoder = nullptr;

+    }

+    return OPUS_OK;

+}

+

+s32 OpusMultiStreamDecodeObject::ResetDecoder() {

+    return opus_multistream_decoder_ctl(decoder, OPUS_RESET_STATE);

+}

+

+s32 OpusMultiStreamDecodeObject::Decode(u32& out_sample_count, u64 output_data,

+                                        u64 output_data_size, u64 input_data, u64 input_data_size) {

+    ASSERT(initialized);

+    out_sample_count = 0;

+

+    if (!state_valid) {

+        return OPUS_INVALID_STATE;

+    }

+

+    auto ret_code_or_samples = opus_multistream_decode(

+        decoder, reinterpret_cast<const u8*>(input_data), static_cast<opus_int32>(input_data_size),

+        reinterpret_cast<opus_int16*>(output_data), static_cast<opus_int32>(output_data_size), 0);

+

+    if (ret_code_or_samples < OPUS_OK) {

+        return ret_code_or_samples;

+    }

+

+    out_sample_count = ret_code_or_samples;

+    return opus_multistream_decoder_ctl(decoder, OPUS_GET_FINAL_RANGE_REQUEST, &final_range);

+}

+

+} // namespace AudioCore::ADSP::OpusDecoder

diff --git a/src/audio_core/adsp/apps/opus/opus_multistream_decode_object.h b/src/audio_core/adsp/apps/opus/opus_multistream_decode_object.h
new file mode 100644
index 000000000..93558ded5
--- /dev/null
+++ b/src/audio_core/adsp/apps/opus/opus_multistream_decode_object.h
@@ -0,0 +1,39 @@
+// SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <opus_multistream.h>
+
+#include "common/common_types.h"
+
+namespace AudioCore::ADSP::OpusDecoder {
+using LibOpusMSDecoder = ::OpusMSDecoder;
+static constexpr u32 DecodeMultiStreamObjectMagic = 0xDEADBEEF;
+
+class OpusMultiStreamDecodeObject {
+public:
+    static u32 GetWorkBufferSize(u32 total_stream_count, u32 stereo_stream_count);
+    static OpusMultiStreamDecodeObject& Initialize(u64 buffer, u64 buffer2);
+
+    s32 InitializeDecoder(u32 sample_rate, u32 total_stream_count, u32 channel_count,
+                          u32 stereo_stream_count, u8* mappings);
+    s32 Shutdown();
+    s32 ResetDecoder();
+    s32 Decode(u32& out_sample_count, u64 output_data, u64 output_data_size, u64 input_data,
+               u64 input_data_size);
+    u32 GetFinalRange() const noexcept {
+        return final_range;
+    }
+
+private:
+    u32 magic;
+    bool initialized;
+    bool state_valid;
+    OpusMultiStreamDecodeObject* self;
+    u32 final_range;
+    LibOpusMSDecoder* decoder;
+};
+static_assert(std::is_trivially_constructible_v<OpusMultiStreamDecodeObject>);
+
+} // namespace AudioCore::ADSP::OpusDecoder
diff --git a/src/audio_core/adsp/apps/opus/shared_memory.h b/src/audio_core/adsp/apps/opus/shared_memory.h
new file mode 100644
index 000000000..c696731ed
--- /dev/null
+++ b/src/audio_core/adsp/apps/opus/shared_memory.h
@@ -0,0 +1,17 @@
+// SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include "common/common_funcs.h"
+#include "common/common_types.h"
+
+namespace AudioCore::ADSP::OpusDecoder {
+
+struct SharedMemory {
+    std::array<u8, 0x100> channel_mapping{};
+    std::array<u64, 16> host_send_data{};
+    std::array<u64, 16> dsp_return_data{};
+};
+
+} // namespace AudioCore::ADSP::OpusDecoder