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Common: Add helper functions for decoding CD-XA ADPCM
This commit is contained in:
Connor McLaughlin
parent
b2632db0a7
commit
2b6ebf9955
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@ -16,10 +16,9 @@ public:
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DATA_SECTOR_SIZE = 2048,
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SECTOR_SYNC_SIZE = 12,
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SECTOR_HEADER_SIZE = 4,
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SECTOR_XA_SUBHEADER_SIZE = 4,
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FRAMES_PER_SECOND = 75, // "sectors"
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SECONDS_PER_MINUTE = 60,
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FRAMES_PER_MINUTE = FRAMES_PER_SECOND * SECONDS_PER_MINUTE,
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FRAMES_PER_MINUTE = FRAMES_PER_SECOND * SECONDS_PER_MINUTE
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};
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enum class ReadMode : u32
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@ -37,33 +36,6 @@ public:
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u8 sector_mode;
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};
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struct XASubHeader
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{
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u8 file_number;
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u8 channel_number;
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union Submode
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{
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u8 bits;
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BitField<u8, bool, 0, 1> eor;
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BitField<u8, bool, 1, 1> video;
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BitField<u8, bool, 2, 1> audio;
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BitField<u8, bool, 3, 1> data;
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BitField<u8, bool, 4, 1> trigger;
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BitField<u8, bool, 5, 1> form2;
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BitField<u8, bool, 6, 1> realtime;
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BitField<u8, bool, 7, 1> eof;
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} submode;
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union Codinginfo
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{
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u8 bits;
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BitField<u8, u8, 0, 2> mono_stereo;
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BitField<u8, u8, 2, 2> sample_rate;
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BitField<u8, u8, 4, 2> bits_per_sample;
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BitField<u8, bool, 6, 1> emphasis;
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} codinginfo;
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};
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// Conversion helpers.
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static constexpr u64 MSFToLBA(u32 pregap_seconds, u32 minute, u32 second, u32 frame);
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static constexpr void LBAToMSF(u32 pregap_seconds, u64 lba, u32* minute, u32* second, u32* frame);
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98
src/common/cd_xa.cpp
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98
src/common/cd_xa.cpp
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@ -0,0 +1,98 @@
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#include "cd_xa.h"
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#include "cd_image.h"
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#include <algorithm>
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#include <array>
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namespace CDXA {
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static constexpr std::array<s32, 4> s_xa_adpcm_filter_table_pos = {{0, 60, 115, 98}};
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static constexpr std::array<s32, 4> s_xa_adpcm_filter_table_neg = {{0, 0, -52, -55}};
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template<bool IS_STEREO, bool IS_8BIT>
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static void DecodeXA_ADPCMChunk(const u8* chunk_ptr, s16* samples, s32* last_samples)
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{
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// The data layout is annoying here. Each word of data is interleaved with the other blocks, requiring multiple
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// passes to decode the whole chunk.
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constexpr u32 NUM_BLOCKS = IS_8BIT ? 4 : 8;
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constexpr u32 WORDS_PER_BLOCK = 28;
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const u8* headers_ptr = chunk_ptr + 4;
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const u8* words_ptr = chunk_ptr + 16;
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for (u32 block = 0; block < NUM_BLOCKS; block++)
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{
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const XA_ADPCMBlockHeader block_header{headers_ptr[block]};
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const u8 shift = block_header.GetShift();
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const u8 filter = block_header.GetFilter();
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const s32 filter_pos = s_xa_adpcm_filter_table_pos[filter];
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const s32 filter_neg = s_xa_adpcm_filter_table_neg[filter];
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s16* out_samples_ptr =
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IS_STEREO ? &samples[(block / 2) * (WORDS_PER_BLOCK * 2) + (block % 2)] : &samples[block * WORDS_PER_BLOCK];
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constexpr u32 out_samples_increment = IS_STEREO ? 2 : 1;
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for (u32 word = 0; word < 28; word++)
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{
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// NOTE: assumes LE
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u32 word_data;
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std::memcpy(&word_data, &words_ptr[word * sizeof(u32)], sizeof(word_data));
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// extract nibble from block
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const u32 nibble = IS_8BIT ? ((word_data >> (block * 8)) & 0xFF) : ((word_data >> (block * 4)) & 0x0F);
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const s16 sample = static_cast<s16>(Truncate16(nibble << 12)) >> shift;
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// mix in previous values
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s32* prev = IS_STEREO ? &last_samples[(block & 1) * 2] : last_samples;
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const s32 interp_sample = s32(sample) + ((prev[0] * filter_pos) + (prev[1] * filter_neg) + 32) / 64;
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// update previous values
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prev[1] = prev[0];
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prev[0] = interp_sample;
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*out_samples_ptr = static_cast<s16>(std::clamp<s32>(interp_sample, -0x8000, 0x7FFF));
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out_samples_ptr += out_samples_increment;
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}
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}
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}
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template<bool IS_STEREO, bool IS_8BIT>
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static void DecodeXA_ADPCMChunks(const u8* chunk_ptr, s16* samples, s32* last_samples)
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{
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constexpr u32 NUM_CHUNKS = 18;
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constexpr u32 CHUNK_SIZE_IN_BYTES = 128;
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constexpr u32 WORDS_PER_CHUNK = 28;
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constexpr u32 SAMPLES_PER_CHUNK = 28 * (IS_8BIT ? 4 : 8);
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for (u32 i = 0; i < NUM_CHUNKS; i++)
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{
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DecodeXA_ADPCMChunk<IS_STEREO, IS_8BIT>(chunk_ptr, samples, last_samples);
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samples += SAMPLES_PER_CHUNK;
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chunk_ptr += CHUNK_SIZE_IN_BYTES;
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}
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}
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void DecodeADPCMSector(const void* data, s16* samples, s32* last_samples)
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{
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const XASubHeader* subheader = reinterpret_cast<const XASubHeader*>(
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reinterpret_cast<const u8*>(data) + CDImage::SECTOR_SYNC_SIZE + sizeof(CDImage::SectorHeader));
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// The XA subheader is repeated?
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const u8* chunk_ptr = reinterpret_cast<const u8*>(data) + CDImage::SECTOR_SYNC_SIZE + sizeof(CDImage::SectorHeader) +
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sizeof(XASubHeader) + 4;
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if (subheader->codinginfo.bits_per_sample != 1)
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{
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if (subheader->codinginfo.mono_stereo != 1)
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DecodeXA_ADPCMChunks<false, false>(chunk_ptr, samples, last_samples);
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else
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DecodeXA_ADPCMChunks<true, false>(chunk_ptr, samples, last_samples);
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}
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else
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{
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if (subheader->codinginfo.mono_stereo != 1)
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DecodeXA_ADPCMChunks<false, true>(chunk_ptr, samples, last_samples);
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else
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DecodeXA_ADPCMChunks<true, true>(chunk_ptr, samples, last_samples);
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}
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}
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} // namespace CDXA
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70
src/common/cd_xa.h
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70
src/common/cd_xa.h
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@ -0,0 +1,70 @@
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#pragma once
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#include "bitfield.h"
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#include "types.h"
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namespace CDXA {
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enum
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{
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XA_SUBHEADER_SIZE = 4,
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XA_ADPCM_SAMPLES_PER_SECTOR_4BIT = 4032, // 28 words * 8 nibbles per word * 18 chunks
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XA_ADPCM_SAMPLES_PER_SECTOR_8BIT = 2016 // 28 words * 4 bytes per word * 18 chunks
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};
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struct XASubHeader
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{
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u8 file_number;
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u8 channel_number;
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union Submode
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{
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u8 bits;
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BitField<u8, bool, 0, 1> eor;
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BitField<u8, bool, 1, 1> video;
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BitField<u8, bool, 2, 1> audio;
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BitField<u8, bool, 3, 1> data;
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BitField<u8, bool, 4, 1> trigger;
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BitField<u8, bool, 5, 1> form2;
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BitField<u8, bool, 6, 1> realtime;
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BitField<u8, bool, 7, 1> eof;
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} submode;
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union Codinginfo
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{
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u8 bits;
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BitField<u8, u8, 0, 2> mono_stereo;
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BitField<u8, u8, 2, 2> sample_rate;
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BitField<u8, u8, 4, 2> bits_per_sample;
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BitField<u8, bool, 6, 1> emphasis;
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bool IsStereo() const { return mono_stereo == 1; }
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bool IsHalfSampleRate() const { return sample_rate == 1; }
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u32 GetSampleRate() const { return sample_rate == 1 ? 18900 : 37800; }
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u32 GetBitsPerSample() const { return bits_per_sample == 1 ? 8 : 4; }
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u32 GetSamplesPerSector() const
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{
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return bits_per_sample == 1 ? XA_ADPCM_SAMPLES_PER_SECTOR_8BIT : XA_ADPCM_SAMPLES_PER_SECTOR_4BIT;
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}
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} codinginfo;
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};
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union XA_ADPCMBlockHeader
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{
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u8 bits;
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BitField<u8, u8, 0, 4> shift;
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BitField<u8, u8, 4, 2> filter;
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// For both 4bit and 8bit ADPCM, reserved shift values 13..15 will act same as shift=9).
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u8 GetShift() const
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{
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const u8 shift_value = shift;
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return (shift_value > 12) ? 9 : shift_value;
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}
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u8 GetFilter() const { return filter; }
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};
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static_assert(sizeof(XA_ADPCMBlockHeader) == 1, "XA-ADPCM block header is one byte");
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// Decodes XA-ADPCM samples in an audio sector. Stereo samples are interleaved with left first.
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void DecodeADPCMSector(const void* data, s16* samples, s32* last_samples);
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} // namespace CDXA
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@ -56,6 +56,7 @@
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<ClInclude Include="state_wrapper.h" />
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<ClInclude Include="types.h" />
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<ClInclude Include="type_registry.h" />
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<ClInclude Include="cd_xa.h" />
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</ItemGroup>
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<ItemGroup>
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<ClCompile Include="audio.cpp" />
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@ -74,6 +75,7 @@
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<ClCompile Include="object_type_info.cpp" />
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<ClCompile Include="property.cpp" />
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<ClCompile Include="state_wrapper.cpp" />
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<ClCompile Include="cd_xa.cpp" />
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</ItemGroup>
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<ItemGroup>
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<Natvis Include="bitfield.natvis" />
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@ -22,6 +22,7 @@
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<ClInclude Include="fifo_queue.h" />
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<ClInclude Include="cd_image.h" />
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<ClInclude Include="audio_stream.h" />
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<ClInclude Include="cd_xa.h" />
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</ItemGroup>
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<ItemGroup>
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<ClCompile Include="hdd_image.cpp" />
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@ -40,6 +41,7 @@
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<ClCompile Include="gl_texture.cpp" />
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<ClCompile Include="cd_image.cpp" />
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<ClCompile Include="audio_stream.cpp" />
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<ClCompile Include="cd_xa.cpp" />
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</ItemGroup>
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<ItemGroup>
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<Natvis Include="bitfield.natvis" />
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