audio_core: Port codec code from Citra for ADPCM decoding.
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@ -4,6 +4,8 @@ add_library(audio_core STATIC
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buffer.h
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cubeb_sink.cpp
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cubeb_sink.h
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codec.cpp
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codec.h
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null_sink.h
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stream.cpp
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stream.h
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@ -0,0 +1,77 @@
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// Copyright 2018 yuzu Emulator Project
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// Licensed under GPLv2 or any later version
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// Refer to the license.txt file included.
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#include <algorithm>
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#include "audio_core/codec.h"
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namespace AudioCore::Codec {
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std::vector<s16> DecodeADPCM(const u8* const data, size_t size, const ADPCM_Coeff& coeff,
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ADPCMState& state) {
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// GC-ADPCM with scale factor and variable coefficients.
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// Frames are 8 bytes long containing 14 samples each.
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// Samples are 4 bits (one nibble) long.
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constexpr size_t FRAME_LEN = 8;
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constexpr size_t SAMPLES_PER_FRAME = 14;
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constexpr std::array<int, 16> SIGNED_NIBBLES = {
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{0, 1, 2, 3, 4, 5, 6, 7, -8, -7, -6, -5, -4, -3, -2, -1}};
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const size_t sample_count = (size / FRAME_LEN) * SAMPLES_PER_FRAME;
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const size_t ret_size =
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sample_count % 2 == 0 ? sample_count : sample_count + 1; // Ensure multiple of two.
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std::vector<s16> ret(ret_size);
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int yn1 = state.yn1, yn2 = state.yn2;
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const size_t NUM_FRAMES =
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(sample_count + (SAMPLES_PER_FRAME - 1)) / SAMPLES_PER_FRAME; // Round up.
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for (size_t framei = 0; framei < NUM_FRAMES; framei++) {
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const int frame_header = data[framei * FRAME_LEN];
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const int scale = 1 << (frame_header & 0xF);
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const int idx = (frame_header >> 4) & 0x7;
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// Coefficients are fixed point with 11 bits fractional part.
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const int coef1 = coeff[idx * 2 + 0];
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const int coef2 = coeff[idx * 2 + 1];
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// Decodes an audio sample. One nibble produces one sample.
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const auto decode_sample = [&](const int nibble) -> s16 {
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const int xn = nibble * scale;
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// We first transform everything into 11 bit fixed point, perform the second order
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// digital filter, then transform back.
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// 0x400 == 0.5 in 11 bit fixed point.
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// Filter: y[n] = x[n] + 0.5 + c1 * y[n-1] + c2 * y[n-2]
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int val = ((xn << 11) + 0x400 + coef1 * yn1 + coef2 * yn2) >> 11;
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// Clamp to output range.
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val = std::clamp<s32>(val, -32768, 32767);
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// Advance output feedback.
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yn2 = yn1;
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yn1 = val;
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return static_cast<s16>(val);
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};
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size_t outputi = framei * SAMPLES_PER_FRAME;
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size_t datai = framei * FRAME_LEN + 1;
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for (size_t i = 0; i < SAMPLES_PER_FRAME && outputi < sample_count; i += 2) {
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const s16 sample1 = decode_sample(SIGNED_NIBBLES[data[datai] >> 4]);
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ret[outputi] = sample1;
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outputi++;
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const s16 sample2 = decode_sample(SIGNED_NIBBLES[data[datai] & 0xF]);
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ret[outputi] = sample2;
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outputi++;
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datai++;
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}
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}
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state.yn1 = yn1;
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state.yn2 = yn2;
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return ret;
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}
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} // namespace AudioCore::Codec
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@ -0,0 +1,44 @@
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// Copyright 2018 yuzu Emulator Project
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// Licensed under GPLv2 or any later version
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// Refer to the license.txt file included.
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#pragma once
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#include <array>
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#include <vector>
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#include "common/common_types.h"
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namespace AudioCore::Codec {
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enum class PcmFormat : u32 {
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Invalid = 0,
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Int8 = 1,
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Int16 = 2,
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Int24 = 3,
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Int32 = 4,
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PcmFloat = 5,
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Adpcm = 6,
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};
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/// See: Codec::DecodeADPCM
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struct ADPCMState {
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// Two historical samples from previous processed buffer,
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// required for ADPCM decoding
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s16 yn1; ///< y[n-1]
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s16 yn2; ///< y[n-2]
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};
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using ADPCM_Coeff = std::array<s16, 16>;
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/**
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* @param data Pointer to buffer that contains ADPCM data to decode
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* @param size Size of buffer in bytes
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* @param coeff ADPCM coefficients
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* @param state ADPCM state, this is updated with new state
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* @return Decoded stereo signed PCM16 data, sample_count in length
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*/
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std::vector<s16> DecodeADPCM(const u8* const data, size_t size, const ADPCM_Coeff& coeff,
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ADPCMState& state);
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}; // namespace AudioCore::Codec
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@ -4,6 +4,8 @@
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#include <array>
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#include <vector>
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#include "audio_core/codec.h"
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#include "common/logging/log.h"
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#include "core/core.h"
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#include "core/hle/ipc_helpers.h"
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@ -200,7 +202,7 @@ void AudOutU::OpenAudioOutImpl(Kernel::HLERequestContext& ctx) {
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rb.Push(RESULT_SUCCESS);
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rb.Push<u32>(DefaultSampleRate);
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rb.Push<u32>(params.channel_count);
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rb.Push<u32>(static_cast<u32>(PcmFormat::Int16));
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rb.Push<u32>(static_cast<u32>(AudioCore::Codec::PcmFormat::Int16));
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rb.Push<u32>(static_cast<u32>(AudioState::Stopped));
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rb.PushIpcInterface<Audio::IAudioOut>(audio_out_interface);
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}
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@ -38,16 +38,6 @@ private:
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void ListAudioOutsImpl(Kernel::HLERequestContext& ctx);
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void OpenAudioOutImpl(Kernel::HLERequestContext& ctx);
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enum class PcmFormat : u32 {
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Invalid = 0,
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Int8 = 1,
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Int16 = 2,
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Int24 = 3,
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Int32 = 4,
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PcmFloat = 5,
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Adpcm = 6,
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};
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};
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} // namespace Service::Audio
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