Initial draft for m4aac decoder

CMakeLists.txt

@@ -293,6 +293,8 @@ set(AJM_LIB src/core/libraries/ajm/ajm.cpp
             src/core/libraries/ajm/ajm_instance.h
             src/core/libraries/ajm/ajm_mp3.cpp
             src/core/libraries/ajm/ajm_mp3.h
+            src/core/libraries/ajm/ajm_m4aac.cpp
+            src/core/libraries/ajm/ajm_m4aac.h
 )
 
 set(AUDIO_LIB src/core/libraries/audio/audioin.cpp

src/core/libraries/ajm/ajm_instance.cpp

@@ -3,6 +3,7 @@
 
 #include "core/libraries/ajm/ajm_at9.h"
 #include "core/libraries/ajm/ajm_instance.h"
+#include "core/libraries/ajm/ajm_m4aac.h"
 #include "core/libraries/ajm/ajm_mp3.h"
 
 #include <magic_enum/magic_enum.hpp>
@@ -47,6 +48,11 @@ AjmInstance::AjmInstance(AjmCodecType codec_type, AjmInstanceFlags flags) : m_fl
                                                   AjmMp3CodecFlags(flags.codec));
         break;
     }
+    case AjmCodecType::M4aacDec: {
+        m_codec = std::make_unique<AjmM4aacDecoder>(AjmFormatEncoding(flags.format),
+                                                    AjmM4aacCodecFlags(flags.codec));
+        break;
+    }
     default:
         UNREACHABLE_MSG("Unimplemented codec type {}", magic_enum::enum_name(codec_type));
     }

src/core/libraries/ajm/ajm_m4aac.cpp

@@ -0,0 +1,44 @@
+// SPDX-FileCopyrightText: Copyright 2024 shadPS4 Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "common/assert.h"
+#include "core/libraries/ajm/ajm_error.h"
+#include "core/libraries/ajm/ajm_m4aac.h"
+#include "core/libraries/error_codes.h"
+
+extern "C" {
+#include <libavcodec/avcodec.h>
+#include <libavutil/opt.h>
+#include <libswresample/swresample.h>
+}
+
+#include "common/support/avdec.h"
+
+namespace Libraries::Ajm {
+AjmM4aacDecoder::AjmM4aacDecoder(AjmFormatEncoding format, AjmM4aacCodecFlags flags)
+    : m_format(format), m_flags(flags), m_codec(avcodec_find_decoder(AV_CODEC_ID_AAC)),
+      m_codec_context(avcodec_alloc_context3(m_codec)), m_parser(av_parser_init(m_codec->id)) {
+    int ret = avcodec_open2(m_codec_context, m_codec, nullptr);
+    ASSERT_MSG(ret >= 0, "Could not open m_codec");
+}
+AjmM4aacDecoder::~AjmM4aacDecoder() {
+    swr_free(&m_swr_context);
+    av_parser_close(m_parser);
+    avcodec_free_context(&m_codec_context);
+}
+void AjmM4aacDecoder::Reset() {}
+void AjmM4aacDecoder::GetInfo(void* out_info) const {}
+AjmSidebandFormat AjmM4aacDecoder::GetFormat() const {
+    return AjmSidebandFormat();
+}
+u32 AjmM4aacDecoder::GetNextFrameSize(const AjmInstanceGapless& gapless) const {
+    return u32();
+}
+std::tuple<u32, u32> AjmM4aacDecoder::ProcessData(std::span<u8>& input, SparseOutputBuffer& output,
+                                                 AjmInstanceGapless& gapless) {
+    return std::tuple<u32, u32>();
+}
+AVFrame* AjmM4aacDecoder::ConvertAudioFrame(AVFrame* frame) {
+    return nullptr;
+}
+} // namespace Libraries::Ajm

src/core/libraries/ajm/ajm_m4aac.h

@@ -0,0 +1,56 @@
+// SPDX-FileCopyrightText: Copyright 2024 shadPS4 Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include "common/types.h"
+#include "core/libraries/ajm/ajm_instance.h"
+
+extern "C" {
+#include <libavcodec/avcodec.h>
+struct SwrContext;
+}
+
+namespace Libraries::Ajm {
+
+enum AjmM4aacCodecFlags : u32 {
+
+};
+DECLARE_ENUM_FLAG_OPERATORS(AjmM4aacCodecFlags)
+
+class AjmM4aacDecoder : public AjmCodec {
+public:
+    explicit AjmM4aacDecoder(AjmFormatEncoding format, AjmM4aacCodecFlags flags);
+    ~AjmM4aacDecoder() override;
+
+    void Reset() override;
+    void Initialize(const void* buffer, u32 buffer_size) override {}
+    void GetInfo(void* out_info) const override;
+    AjmSidebandFormat GetFormat() const override;
+    u32 GetNextFrameSize(const AjmInstanceGapless& gapless) const override;
+    std::tuple<u32, u32> ProcessData(std::span<u8>& input, SparseOutputBuffer& output,
+                                     AjmInstanceGapless& gapless) override;
+
+private:
+    template <class T>
+    size_t WriteOutputPCM(AVFrame* frame, SparseOutputBuffer& output, u32 skipped_samples,
+                          u32 max_pcm) {
+        std::span<T> pcm_data(reinterpret_cast<T*>(frame->data[0]),
+                              frame->nb_samples * frame->ch_layout.nb_channels);
+        pcm_data = pcm_data.subspan(skipped_samples * frame->ch_layout.nb_channels);
+        return output.Write(pcm_data.subspan(0, std::min(u32(pcm_data.size()), max_pcm)));
+    }
+
+    AVFrame* ConvertAudioFrame(AVFrame* frame);
+
+    const AjmFormatEncoding m_format;
+    const AjmM4aacCodecFlags m_flags;
+    const AVCodec* m_codec = nullptr;
+    AVCodecContext* m_codec_context = nullptr;
+    AVCodecParserContext* m_parser = nullptr;
+    SwrContext* m_swr_context = nullptr;
+    std::optional<u32> m_header;
+    u32 m_frame_samples = 0;
+};
+
+} // namespace Libraries::Ajm