ajm: support for m4aac (#3880)

* ajm m4aac

* fix build on unix

* small tunes

* skip 2 frames if nodelay is not set, change to google repo

.gitmodules

@@ -120,3 +120,6 @@
 [submodule "externals/miniz"]
 	path = externals/miniz
 	url = https://github.com/richgel999/miniz
+[submodule "externals/aacdec/fdk-aac"]
+	path = externals/aacdec/fdk-aac
+	url = https://android.googlesource.com/platform/external/aac

CMakeLists.txt

@@ -262,6 +262,8 @@ include_directories(src)
 
 set(AJM_LIB src/core/libraries/ajm/ajm.cpp
             src/core/libraries/ajm/ajm.h
+            src/core/libraries/ajm/ajm_aac.cpp
+            src/core/libraries/ajm/ajm_aac.h
             src/core/libraries/ajm/ajm_at9.cpp
             src/core/libraries/ajm/ajm_at9.h
             src/core/libraries/ajm/ajm_batch.cpp
@@ -1085,7 +1087,7 @@ create_target_directory_groups(shadps4)
 
 target_link_libraries(shadps4 PRIVATE magic_enum::magic_enum fmt::fmt toml11::toml11 tsl::robin_map xbyak::xbyak Tracy::TracyClient RenderDoc::API FFmpeg::ffmpeg Dear_ImGui gcn half::half ZLIB::ZLIB PNG::PNG)
 target_link_libraries(shadps4 PRIVATE Boost::headers GPUOpen::VulkanMemoryAllocator LibAtrac9 sirit Vulkan::Headers xxHash::xxhash Zydis::Zydis glslang::glslang SDL3::SDL3 SDL3_mixer::SDL3_mixer pugixml::pugixml)
-target_link_libraries(shadps4 PRIVATE stb::headers libusb::usb lfreist-hwinfo::hwinfo nlohmann_json::nlohmann_json miniz)
+target_link_libraries(shadps4 PRIVATE stb::headers libusb::usb lfreist-hwinfo::hwinfo nlohmann_json::nlohmann_json miniz fdk-aac)
 
 target_compile_definitions(shadps4 PRIVATE IMGUI_USER_CONFIG="imgui/imgui_config.h")
 target_compile_definitions(Dear_ImGui PRIVATE IMGUI_USER_CONFIG="${PROJECT_SOURCE_DIR}/src/imgui/imgui_config.h")

externals/CMakeLists.txt

@@ -258,6 +258,10 @@ if (WIN32)
 add_subdirectory(ext-wepoll)
 endif()
 
+if (NOT TARGET fdk-aac)
+add_subdirectory(aacdec)
+endif()
+
 #nlohmann json 
 set(JSON_BuildTests OFF CACHE INTERNAL "")
 add_subdirectory(json)

externals/aacdec/CMakeLists.txt

@@ -0,0 +1,154 @@
+# SPDX-FileCopyrightText: Copyright 2026 shadPS4 Emulator Project
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+set(AACDEC_SRC
+    fdk-aac/libAACdec/src/FDK_delay.cpp
+    fdk-aac/libAACdec/src/aac_ram.cpp
+    fdk-aac/libAACdec/src/aac_rom.cpp
+    fdk-aac/libAACdec/src/aacdec_drc.cpp
+    fdk-aac/libAACdec/src/aacdec_hcr.cpp
+    fdk-aac/libAACdec/src/aacdec_hcr_bit.cpp
+    fdk-aac/libAACdec/src/aacdec_hcrs.cpp
+    fdk-aac/libAACdec/src/aacdec_pns.cpp
+    fdk-aac/libAACdec/src/aacdec_tns.cpp
+    fdk-aac/libAACdec/src/aacdecoder.cpp
+    fdk-aac/libAACdec/src/aacdecoder_lib.cpp
+    fdk-aac/libAACdec/src/block.cpp
+    fdk-aac/libAACdec/src/channel.cpp
+    fdk-aac/libAACdec/src/channelinfo.cpp
+    fdk-aac/libAACdec/src/conceal.cpp
+    fdk-aac/libAACdec/src/ldfiltbank.cpp
+    fdk-aac/libAACdec/src/pulsedata.cpp
+    fdk-aac/libAACdec/src/rvlc.cpp
+    fdk-aac/libAACdec/src/rvlcbit.cpp
+    fdk-aac/libAACdec/src/rvlcconceal.cpp
+    fdk-aac/libAACdec/src/stereo.cpp
+    fdk-aac/libAACdec/src/usacdec_ace_d4t64.cpp
+    fdk-aac/libAACdec/src/usacdec_ace_ltp.cpp
+    fdk-aac/libAACdec/src/usacdec_acelp.cpp
+    fdk-aac/libAACdec/src/usacdec_fac.cpp
+    fdk-aac/libAACdec/src/usacdec_lpc.cpp
+    fdk-aac/libAACdec/src/usacdec_lpd.cpp
+    fdk-aac/libAACdec/src/usacdec_rom.cpp
+)
+
+set(FDK_SRC
+    fdk-aac/libFDK/src/FDK_bitbuffer.cpp
+    fdk-aac/libFDK/src/FDK_core.cpp
+    fdk-aac/libFDK/src/FDK_crc.cpp
+    fdk-aac/libFDK/src/FDK_decorrelate.cpp
+    fdk-aac/libFDK/src/FDK_hybrid.cpp
+    fdk-aac/libFDK/src/FDK_lpc.cpp
+    fdk-aac/libFDK/src/FDK_matrixCalloc.cpp
+    fdk-aac/libFDK/src/FDK_qmf_domain.cpp
+    fdk-aac/libFDK/src/FDK_tools_rom.cpp
+    fdk-aac/libFDK/src/FDK_trigFcts.cpp
+    fdk-aac/libFDK/src/autocorr2nd.cpp
+    fdk-aac/libFDK/src/dct.cpp
+    fdk-aac/libFDK/src/fft.cpp
+    fdk-aac/libFDK/src/fft_rad2.cpp
+    fdk-aac/libFDK/src/fixpoint_math.cpp
+    fdk-aac/libFDK/src/huff_nodes.cpp
+    fdk-aac/libFDK/src/mdct.cpp
+    fdk-aac/libFDK/src/nlc_dec.cpp
+    fdk-aac/libFDK/src/qmf.cpp
+    fdk-aac/libFDK/src/scale.cpp
+)
+
+set(SYS_SRC
+    fdk-aac/libSYS/src/genericStds.cpp
+    fdk-aac/libSYS/src/syslib_channelMapDescr.cpp
+)
+
+set(ARITHCODING_SRC
+    fdk-aac/libArithCoding/src/ac_arith_coder.cpp
+)
+
+set(MPEGTPDEC_SRC
+    fdk-aac/libMpegTPDec/src/tpdec_adif.cpp
+    fdk-aac/libMpegTPDec/src/tpdec_adts.cpp
+    fdk-aac/libMpegTPDec/src/tpdec_asc.cpp
+    fdk-aac/libMpegTPDec/src/tpdec_drm.cpp
+    fdk-aac/libMpegTPDec/src/tpdec_latm.cpp
+    fdk-aac/libMpegTPDec/src/tpdec_lib.cpp
+)
+
+set(SBRDEC_SRC
+    fdk-aac/libSBRdec/src/HFgen_preFlat.cpp
+    fdk-aac/libSBRdec/src/env_calc.cpp
+    fdk-aac/libSBRdec/src/env_dec.cpp
+    fdk-aac/libSBRdec/src/env_extr.cpp
+    fdk-aac/libSBRdec/src/hbe.cpp
+    fdk-aac/libSBRdec/src/huff_dec.cpp
+    fdk-aac/libSBRdec/src/lpp_tran.cpp
+    fdk-aac/libSBRdec/src/psbitdec.cpp
+    fdk-aac/libSBRdec/src/psdec.cpp
+    fdk-aac/libSBRdec/src/psdec_drm.cpp
+    fdk-aac/libSBRdec/src/psdecrom_drm.cpp
+    fdk-aac/libSBRdec/src/pvc_dec.cpp
+    fdk-aac/libSBRdec/src/sbr_deb.cpp
+    fdk-aac/libSBRdec/src/sbr_dec.cpp
+    fdk-aac/libSBRdec/src/sbr_ram.cpp
+    fdk-aac/libSBRdec/src/sbr_rom.cpp
+    fdk-aac/libSBRdec/src/sbrdec_drc.cpp
+    fdk-aac/libSBRdec/src/sbrdec_freq_sca.cpp
+    fdk-aac/libSBRdec/src/sbrdecoder.cpp
+)
+
+set(PCMUTILS_SRC
+  fdk-aac/libPCMutils/src/limiter.cpp
+  fdk-aac/libPCMutils/src/pcm_utils.cpp
+  fdk-aac/libPCMutils/src/pcmdmx_lib.cpp
+)
+
+set(DRCDEC_SRC
+  fdk-aac/libDRCdec/src/FDK_drcDecLib.cpp
+  fdk-aac/libDRCdec/src/drcDec_gainDecoder.cpp
+  fdk-aac/libDRCdec/src/drcDec_reader.cpp
+  fdk-aac/libDRCdec/src/drcDec_rom.cpp
+  fdk-aac/libDRCdec/src/drcDec_selectionProcess.cpp
+  fdk-aac/libDRCdec/src/drcDec_tools.cpp
+  fdk-aac/libDRCdec/src/drcGainDec_init.cpp
+  fdk-aac/libDRCdec/src/drcGainDec_preprocess.cpp
+  fdk-aac/libDRCdec/src/drcGainDec_process.cpp
+)
+
+set(SACDEC_SRC
+  fdk-aac/libSACdec/src/sac_bitdec.cpp
+  fdk-aac/libSACdec/src/sac_calcM1andM2.cpp
+  fdk-aac/libSACdec/src/sac_dec.cpp
+  fdk-aac/libSACdec/src/sac_dec_conceal.cpp
+  fdk-aac/libSACdec/src/sac_dec_lib.cpp
+  fdk-aac/libSACdec/src/sac_process.cpp
+  fdk-aac/libSACdec/src/sac_qmf.cpp
+  fdk-aac/libSACdec/src/sac_reshapeBBEnv.cpp
+  fdk-aac/libSACdec/src/sac_rom.cpp
+  fdk-aac/libSACdec/src/sac_smoothing.cpp
+  fdk-aac/libSACdec/src/sac_stp.cpp
+  fdk-aac/libSACdec/src/sac_tsd.cpp
+)
+
+add_library(fdk-aac
+  ${AACDEC_SRC}
+  ${FDK_SRC}
+  ${SYS_SRC}
+  ${ARITHCODING_SRC}
+  ${MPEGTPDEC_SRC}
+  ${SBRDEC_SRC}
+  ${PCMUTILS_SRC}
+  ${DRCDEC_SRC}
+  ${SACDEC_SRC}
+)
+
+target_include_directories(fdk-aac
+  PUBLIC
+    fdk-aac/libAACdec/include
+    fdk-aac/libFDK/include
+    fdk-aac/libSYS/include
+    fdk-aac/libArithCoding/include
+    fdk-aac/libMpegTPDec/include
+    fdk-aac/libSBRdec/include
+    fdk-aac/libPCMutils/include
+    fdk-aac/libDRCdec/include
+    fdk-aac/libSACdec/include
+)

src/core/libraries/ajm/ajm.cpp

@@ -144,9 +144,8 @@ int PS4_SYSV_ABI sceAjmInitialize(s64 reserved, u32* p_context_id) {
     return ORBIS_OK;
 }
 
-int PS4_SYSV_ABI sceAjmInstanceCodecType() {
-    LOG_ERROR(Lib_Ajm, "(STUBBED) called");
-    return ORBIS_OK;
+AjmCodecType PS4_SYSV_ABI sceAjmInstanceCodecType(u32 instance_id) {
+    return static_cast<AjmCodecType>((instance_id >> 14) & 0x1F);
 }
 
 int PS4_SYSV_ABI sceAjmInstanceCreate(u32 context_id, AjmCodecType codec_type,

src/core/libraries/ajm/ajm.h

@@ -82,8 +82,6 @@ enum class AjmStatisticsFlags : u64 {
 DECLARE_ENUM_FLAG_OPERATORS(AjmStatisticsFlags)
 
 union AjmStatisticsJobFlags {
-    AjmStatisticsJobFlags(AjmJobFlags job_flags) : raw(job_flags.raw) {}
-
     u64 raw;
     struct {
         u64 version : 3;
@@ -217,7 +215,7 @@ int PS4_SYSV_ABI sceAjmDecMp3ParseFrame(const u8* stream, u32 stream_size, int p
                                         AjmDecMp3ParseFrame* frame);
 int PS4_SYSV_ABI sceAjmFinalize();
 int PS4_SYSV_ABI sceAjmInitialize(s64 reserved, u32* out_context);
-int PS4_SYSV_ABI sceAjmInstanceCodecType();
+AjmCodecType PS4_SYSV_ABI sceAjmInstanceCodecType(u32 instance_id);
 int PS4_SYSV_ABI sceAjmInstanceCreate(u32 context, AjmCodecType codec_type, AjmInstanceFlags flags,
                                       u32* instance);
 int PS4_SYSV_ABI sceAjmInstanceDestroy(u32 context, u32 instance);

src/core/libraries/ajm/ajm_aac.cpp

@@ -0,0 +1,194 @@
+// SPDX-FileCopyrightText: Copyright 2026 shadPS4 Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "ajm.h"
+#include "ajm_aac.h"
+#include "ajm_result.h"
+
+// using this internal header to manually configure the decoder in RAW mode
+#include "externals/aacdec/fdk-aac/libAACdec/src/aacdecoder.h"
+
+#include <aacdecoder_lib.h>
+#include <magic_enum/magic_enum.hpp>
+
+namespace Libraries::Ajm {
+
+AjmAacDecoder::AjmAacDecoder(AjmFormatEncoding format, AjmAacCodecFlags flags, u32 channels)
+    : m_format(format), m_flags(flags), m_channels(channels), m_pcm_buffer(2048 * 8),
+      m_skip_frames(True(flags & AjmAacCodecFlags::EnableNondelayOutput) ? 0 : 2) {}
+
+AjmAacDecoder::~AjmAacDecoder() {
+    aacDecoder_Close(m_decoder);
+}
+
+TRANSPORT_TYPE TransportTypeFromConfigType(ConfigType config_type) {
+    switch (config_type) {
+    case ConfigType::ADTS:
+        return TT_MP4_ADTS;
+    case ConfigType::RAW:
+        return TT_MP4_RAW;
+    default:
+        UNREACHABLE();
+    }
+}
+
+static UINT g_freq[] = {
+    96000, 88200, 64000, 48000, 44100, 32000, 24000, 22050, 16000, 12000, 11025, 8000,
+};
+
+void AjmAacDecoder::Reset() {
+    if (m_decoder) {
+        aacDecoder_Close(m_decoder);
+    }
+
+    m_decoder = aacDecoder_Open(TransportTypeFromConfigType(m_init_params.config_type), 1);
+    if (m_init_params.config_type == ConfigType::RAW) {
+        // Manually configure the decoder
+        // Things may be incorrect due to limited documentation
+        CSAudioSpecificConfig asc{};
+        asc.m_aot = AOT_AAC_LC;
+        asc.m_samplingFrequency = g_freq[m_init_params.sampling_freq_type];
+        asc.m_samplingFrequencyIndex = m_init_params.sampling_freq_type;
+        asc.m_samplesPerFrame = 1024;
+        asc.m_epConfig = -1;
+        switch (m_channels) {
+        case 0:
+            asc.m_channelConfiguration = 2;
+            break;
+        case 1:
+        case 2:
+        case 3:
+        case 4:
+        case 5:
+        case 6:
+            asc.m_channelConfiguration = m_channels;
+            break;
+        case 7:
+            asc.m_channelConfiguration = 11;
+            break;
+        case 8:
+            asc.m_channelConfiguration = 12; // 7, 12 or 14 ?
+            break;
+        default:
+            UNREACHABLE();
+        }
+
+        UCHAR changed = 1;
+        CAacDecoder_Init(m_decoder, &asc, AC_CM_ALLOC_MEM, &changed);
+    }
+    m_skip_frames = True(m_flags & AjmAacCodecFlags::EnableNondelayOutput) ? 0 : 2;
+}
+
+void AjmAacDecoder::Initialize(const void* buffer, u32 buffer_size) {
+    ASSERT(buffer_size == 8);
+    m_init_params = *reinterpret_cast<const InitializeParameters*>(buffer);
+    Reset();
+}
+
+void AjmAacDecoder::GetInfo(void* out_info) const {
+    auto* codec_info = reinterpret_cast<AjmSidebandDecM4aacCodecInfo*>(out_info);
+    *codec_info = {
+        .heaac = True(m_flags & AjmAacCodecFlags::EnableSbrDecode),
+    };
+}
+
+AjmSidebandFormat AjmAacDecoder::GetFormat() const {
+    const auto* const info = aacDecoder_GetStreamInfo(m_decoder);
+    return {
+        .num_channels = static_cast<u32>(info->numChannels),
+        .channel_mask = GetChannelMask(info->numChannels),
+        .sampl_freq = static_cast<u32>(info->sampleRate),
+        .sample_encoding = m_format, // AjmFormatEncoding
+        .bitrate = static_cast<u32>(info->bitRate),
+    };
+}
+
+u32 AjmAacDecoder::GetMinimumInputSize() const {
+    return 0;
+}
+
+u32 AjmAacDecoder::GetNextFrameSize(const AjmInstanceGapless& gapless) const {
+    const auto* const info = aacDecoder_GetStreamInfo(m_decoder);
+    if (info->aacSamplesPerFrame <= 0) {
+        return 0;
+    }
+    const auto skip_samples = std::min<u32>(gapless.current.skip_samples, info->frameSize);
+    const auto samples =
+        gapless.init.total_samples != 0
+            ? std::min<u32>(gapless.current.total_samples, info->frameSize - skip_samples)
+            : info->frameSize - skip_samples;
+    return samples * info->numChannels * GetPCMSize(m_format);
+}
+
+DecoderResult AjmAacDecoder::ProcessData(std::span<u8>& input, SparseOutputBuffer& output,
+                                         AjmInstanceGapless& gapless) {
+    DecoderResult result{};
+
+    // Discard the previous contents of the internal buffer and replace them with new ones
+    aacDecoder_SetParam(m_decoder, AAC_TPDEC_CLEAR_BUFFER, 1);
+    UCHAR* buffers[] = {input.data()};
+    const UINT sizes[] = {static_cast<UINT>(input.size())};
+    UINT valid = sizes[0];
+    aacDecoder_Fill(m_decoder, buffers, sizes, &valid);
+    auto ret = aacDecoder_DecodeFrame(m_decoder, reinterpret_cast<s16*>(m_pcm_buffer.data()),
+                                      m_pcm_buffer.size() / 2, 0);
+
+    switch (ret) {
+    case AAC_DEC_OK:
+        break;
+    case AAC_DEC_NOT_ENOUGH_BITS:
+        result.result = ORBIS_AJM_RESULT_PARTIAL_INPUT;
+        return result;
+    default:
+        LOG_ERROR(Lib_Ajm, "aacDecoder_DecodeFrame failed ret = {:#x}", static_cast<u32>(ret));
+        result.result = ORBIS_AJM_RESULT_CODEC_ERROR | ORBIS_AJM_RESULT_FATAL;
+        result.internal_result = ret;
+        return result;
+    }
+
+    const auto* const info = aacDecoder_GetStreamInfo(m_decoder);
+    auto bytes_used = info->numTotalBytes;
+
+    result.frames_decoded += 1;
+    input = input.subspan(bytes_used);
+
+    if (m_skip_frames > 0) {
+        --m_skip_frames;
+        return result;
+    }
+
+    u32 skip_samples = 0;
+    if (gapless.current.skip_samples > 0) {
+        skip_samples = std::min<u16>(info->frameSize, gapless.current.skip_samples);
+        gapless.current.skip_samples -= skip_samples;
+    }
+
+    const auto max_samples =
+        gapless.init.total_samples != 0 ? gapless.current.total_samples : info->aacSamplesPerFrame;
+
+    size_t pcm_written = 0;
+    switch (m_format) {
+    case AjmFormatEncoding::S16:
+        pcm_written = WriteOutputSamples<s16>(output, skip_samples * info->numChannels,
+                                              max_samples * info->numChannels);
+        break;
+    case AjmFormatEncoding::S32:
+        UNREACHABLE_MSG("NOT IMPLEMENTED");
+        break;
+    case AjmFormatEncoding::Float:
+        UNREACHABLE_MSG("NOT IMPLEMENTED");
+        break;
+    default:
+        UNREACHABLE();
+    }
+
+    result.samples_written = pcm_written / info->numChannels;
+    gapless.current.skipped_samples += info->frameSize - result.samples_written;
+    if (gapless.init.total_samples != 0) {
+        gapless.current.total_samples -= result.samples_written;
+    }
+
+    return result;
+}
+
+} // namespace Libraries::Ajm

src/core/libraries/ajm/ajm_aac.h

@@ -0,0 +1,73 @@
+// SPDX-FileCopyrightText: Copyright 2026 shadPS4 Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include "common/enum.h"
+#include "common/types.h"
+#include "core/libraries/ajm/ajm_instance.h"
+
+#include <span>
+#include <vector>
+
+struct AAC_DECODER_INSTANCE;
+
+namespace Libraries::Ajm {
+
+enum ConfigType : u32 {
+    ADTS = 1,
+    RAW = 2,
+};
+
+enum AjmAacCodecFlags : u32 {
+    EnableSbrDecode = 1 << 0,
+    EnableNondelayOutput = 1 << 1,
+    SurroundChannelInterleaveOrderExtlExtrLsRs = 1 << 2,
+    SurroundChannelInterleaveOrderLsRsExtlExtr = 1 << 3,
+};
+DECLARE_ENUM_FLAG_OPERATORS(AjmAacCodecFlags)
+
+struct AjmSidebandDecM4aacCodecInfo {
+    u32 heaac;
+    u32 reserved;
+};
+
+struct AjmAacDecoder final : AjmCodec {
+    explicit AjmAacDecoder(AjmFormatEncoding format, AjmAacCodecFlags flags, u32 channels);
+    ~AjmAacDecoder() 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 GetMinimumInputSize() const override;
+    u32 GetNextFrameSize(const AjmInstanceGapless& gapless) const override;
+    DecoderResult ProcessData(std::span<u8>& input, SparseOutputBuffer& output,
+                              AjmInstanceGapless& gapless) override;
+
+private:
+    struct InitializeParameters {
+        ConfigType config_type;
+        u32 sampling_freq_type;
+    };
+
+    template <class T>
+    size_t WriteOutputSamples(SparseOutputBuffer& output, u32 skipped_pcm, u32 max_pcm) {
+        std::span<T> pcm_data{reinterpret_cast<T*>(m_pcm_buffer.data()),
+                              m_pcm_buffer.size() / sizeof(T)};
+        pcm_data = pcm_data.subspan(skipped_pcm);
+        const auto pcm_size = std::min(u32(pcm_data.size()), max_pcm);
+        return output.Write(pcm_data.subspan(0, pcm_size));
+    }
+
+    const AjmFormatEncoding m_format;
+    const AjmAacCodecFlags m_flags;
+    const u32 m_channels;
+    std::vector<u8> m_pcm_buffer;
+
+    u32 m_skip_frames = 0;
+    InitializeParameters m_init_params = {};
+    AAC_DECODER_INSTANCE* m_decoder = nullptr;
+};
+
+} // namespace Libraries::Ajm

src/core/libraries/ajm/ajm_at9.cpp

@@ -54,7 +54,7 @@ struct RIFFHeader {
 };
 static_assert(sizeof(RIFFHeader) == 12);
 
-AjmAt9Decoder::AjmAt9Decoder(AjmFormatEncoding format, AjmAt9CodecFlags flags)
+AjmAt9Decoder::AjmAt9Decoder(AjmFormatEncoding format, AjmAt9CodecFlags flags, u32)
     : m_format(format), m_flags(flags), m_handle(Atrac9GetHandle()) {}
 
 AjmAt9Decoder::~AjmAt9Decoder() {

src/core/libraries/ajm/ajm_at9.h

@@ -3,6 +3,7 @@
 
 #pragma once
 
+#include "common/enum.h"
 #include "common/types.h"
 #include "core/libraries/ajm/ajm_instance.h"
 
@@ -13,8 +14,6 @@
 
 namespace Libraries::Ajm {
 
-constexpr s32 ORBIS_AJM_DEC_AT9_MAX_CHANNELS = 8;
-
 enum AjmAt9CodecFlags : u32 {
     ParseRiffHeader = 1 << 0,
     NonInterleavedOutput = 1 << 8,
@@ -29,7 +28,7 @@ struct AjmSidebandDecAt9CodecInfo {
 };
 
 struct AjmAt9Decoder final : AjmCodec {
-    explicit AjmAt9Decoder(AjmFormatEncoding format, AjmAt9CodecFlags flags);
+    explicit AjmAt9Decoder(AjmFormatEncoding format, AjmAt9CodecFlags flags, u32 channels);
     ~AjmAt9Decoder() override;
 
     void Reset() override;

src/core/libraries/ajm/ajm_batch.cpp

@@ -165,7 +165,7 @@ AjmJob AjmStatisticsJobFromBatchBuffer(u32 instance_id, AjmBatchBuffer batch_buf
     ASSERT(job_flags.has_value());
     job.flags = job_flags.value();
 
-    AjmStatisticsJobFlags flags(job.flags);
+    AjmStatisticsJobFlags flags{.raw = job.flags.raw};
     if (input_control_buffer.has_value()) {
         AjmBatchBuffer input_batch(input_control_buffer.value());
         if (True(flags.statistics_flags & AjmStatisticsFlags::Engine)) {

src/core/libraries/ajm/ajm_context.cpp

@@ -18,7 +18,8 @@
 
 namespace Libraries::Ajm {
 
-static constexpr u32 ORBIS_AJM_WAIT_INFINITE = -1;
+constexpr u32 ORBIS_AJM_WAIT_INFINITE = -1;
+constexpr int INSTANCE_ID_MASK = 0x3FFF;
 
 AjmContext::AjmContext() {
     worker_thread = std::jthread([this](std::stop_token stop) { this->WorkerThread(stop); });
@@ -84,7 +85,7 @@ void AjmContext::ProcessBatch(u32 id, std::span<AjmJob> jobs) {
             std::shared_ptr<AjmInstance> instance;
             {
                 std::shared_lock lock(instances_mutex);
-                auto* p_instance = instances.Get(job.instance_id);
+                auto* p_instance = instances.Get(job.instance_id & INSTANCE_ID_MASK);
                 ASSERT_MSG(p_instance != nullptr, "Attempting to execute job on null instance");
                 instance = *p_instance;
             }
@@ -176,15 +177,15 @@ s32 AjmContext::InstanceCreate(AjmCodecType codec_type, AjmInstanceFlags flags,
     if (!opt_index.has_value()) {
         return ORBIS_AJM_ERROR_OUT_OF_RESOURCES;
     }
-    *out_instance = opt_index.value();
+    *out_instance = opt_index.value() | (static_cast<u32>(codec_type) << 14);
 
     LOG_INFO(Lib_Ajm, "instance = {}", *out_instance);
     return ORBIS_OK;
 }
 
-s32 AjmContext::InstanceDestroy(u32 instance) {
+s32 AjmContext::InstanceDestroy(u32 instance_id) {
     std::unique_lock lock(instances_mutex);
-    if (!instances.Destroy(instance)) {
+    if (!instances.Destroy(instance_id & INSTANCE_ID_MASK)) {
         return ORBIS_AJM_ERROR_INVALID_INSTANCE;
     }
     return ORBIS_OK;

src/core/libraries/ajm/ajm_instance.cpp

@@ -1,6 +1,7 @@
 // SPDX-FileCopyrightText: Copyright 2024 shadPS4 Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
+#include "ajm_aac.h"
 #include "ajm_at9.h"
 #include "ajm_instance.h"
 #include "ajm_mp3.h"
@@ -26,13 +27,18 @@ u8 GetPCMSize(AjmFormatEncoding format) {
 AjmInstance::AjmInstance(AjmCodecType codec_type, AjmInstanceFlags flags) : m_flags(flags) {
     switch (codec_type) {
     case AjmCodecType::At9Dec: {
-        m_codec = std::make_unique<AjmAt9Decoder>(AjmFormatEncoding(flags.format),
-                                                  AjmAt9CodecFlags(flags.codec));
+        m_codec = std::make_unique<AjmAt9Decoder>(
+            AjmFormatEncoding(flags.format), AjmAt9CodecFlags(flags.codec), u32(flags.channels));
         break;
     }
     case AjmCodecType::Mp3Dec: {
-        m_codec = std::make_unique<AjmMp3Decoder>(AjmFormatEncoding(flags.format),
-                                                  AjmMp3CodecFlags(flags.codec));
+        m_codec = std::make_unique<AjmMp3Decoder>(
+            AjmFormatEncoding(flags.format), AjmMp3CodecFlags(flags.codec), u32(flags.channels));
+        break;
+    }
+    case AjmCodecType::M4aacDec: {
+        m_codec = std::make_unique<AjmAacDecoder>(
+            AjmFormatEncoding(flags.format), AjmAacCodecFlags(flags.codec), u32(flags.channels));
         break;
     }
     default:

src/core/libraries/ajm/ajm_mp3.cpp

@@ -105,7 +105,7 @@ AVFrame* AjmMp3Decoder::ConvertAudioFrame(AVFrame* frame) {
     return new_frame;
 }
 
-AjmMp3Decoder::AjmMp3Decoder(AjmFormatEncoding format, AjmMp3CodecFlags flags)
+AjmMp3Decoder::AjmMp3Decoder(AjmFormatEncoding format, AjmMp3CodecFlags flags, u32)
     : m_format(format), m_flags(flags), m_codec(avcodec_find_decoder(AV_CODEC_ID_MP3)),
       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);
@@ -311,7 +311,8 @@ int AjmMp3Decoder::ParseMp3Header(const u8* p_begin, u32 stream_size, int parse_
 
     BitReader reader(p_current);
     if (header->protection_type == 0) {
-        reader.Skip(16); // crc = reader.Read<u16>(16);
+        // crc = reader.Read<u16>(16);
+        reader.Skip(16);
     }
 
     if (header->version == Mp3AudioVersion::V1) {

src/core/libraries/ajm/ajm_mp3.h

@@ -3,6 +3,7 @@
 
 #pragma once
 
+#include "common/enum.h"
 #include "common/types.h"
 #include "core/libraries/ajm/ajm_instance.h"
 
@@ -63,7 +64,7 @@ struct AjmSidebandDecMp3CodecInfo {
 
 class AjmMp3Decoder : public AjmCodec {
 public:
-    explicit AjmMp3Decoder(AjmFormatEncoding format, AjmMp3CodecFlags flags);
+    explicit AjmMp3Decoder(AjmFormatEncoding format, AjmMp3CodecFlags flags, u32 channels);
     ~AjmMp3Decoder() override;
 
     void Reset() override;