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CDROM: Fix handling of 8-bit ADPCM and decoder overruns
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Fixes pops in menu music in Simple 1500 Series Vol. 92 - The Tozan
RPG - Ginrei no Hasha.

I haven't seen anything that _properly_ uses 8-bit ADPCM yet. The above
game does, but only in the inaudible portion of the start of the track.
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@stenzek
stenzek committed Jul 23, 2024
1 parent 861d4a5 commit 5ec9c8a
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Showing 6 changed files with 164 additions and 200 deletions.
183 changes: 164 additions & 19 deletions src/core/cdrom.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -12,7 +12,6 @@
#include "system.h"

#include "util/cd_image.h"
#include "util/cd_xa.h"
#include "util/imgui_manager.h"
#include "util/iso_reader.h"
#include "util/state_wrapper.h"
Expand Down Expand Up @@ -42,6 +41,10 @@ enum : u32
DATA_SECTOR_OUTPUT_SIZE = CDImage::DATA_SECTOR_SIZE,
SECTOR_SYNC_SIZE = CDImage::SECTOR_SYNC_SIZE,
SECTOR_HEADER_SIZE = CDImage::SECTOR_HEADER_SIZE,

XA_SUBHEADER_SIZE = 4,
XA_ADPCM_SAMPLES_PER_SECTOR_4BIT = 4032, // 28 words * 8 nibbles per word * 18 chunks
XA_ADPCM_SAMPLES_PER_SECTOR_8BIT = 2016, // 28 words * 4 bytes per word * 18 chunks
XA_RESAMPLE_RING_BUFFER_SIZE = 32,
XA_RESAMPLE_ZIGZAG_TABLE_SIZE = 29,
XA_RESAMPLE_NUM_ZIGZAG_TABLES = 7,
Expand Down Expand Up @@ -214,6 +217,61 @@ union RequestRegister
BitField<u8, bool, 7, 1> BFRD;
};

struct XASubHeader
{
u8 file_number;
u8 channel_number;

union Submode
{
u8 bits;
BitField<u8, bool, 0, 1> eor;
BitField<u8, bool, 1, 1> video;
BitField<u8, bool, 2, 1> audio;
BitField<u8, bool, 3, 1> data;
BitField<u8, bool, 4, 1> trigger;
BitField<u8, bool, 5, 1> form2;
BitField<u8, bool, 6, 1> realtime;
BitField<u8, bool, 7, 1> eof;
} submode;

union Codinginfo
{
u8 bits;

BitField<u8, bool, 0, 1> mono_stereo;
BitField<u8, bool, 2, 1> sample_rate;
BitField<u8, bool, 4, 1> bits_per_sample;
BitField<u8, bool, 6, 1> emphasis;

ALWAYS_INLINE bool IsStereo() const { return mono_stereo; }
ALWAYS_INLINE bool IsHalfSampleRate() const { return sample_rate; }
ALWAYS_INLINE bool Is8BitADPCM() const { return bits_per_sample; }
u32 GetSamplesPerSector() const
{
return bits_per_sample ? XA_ADPCM_SAMPLES_PER_SECTOR_8BIT : XA_ADPCM_SAMPLES_PER_SECTOR_4BIT;
}
} codinginfo;
};

union XA_ADPCMBlockHeader
{
u8 bits;

BitField<u8, u8, 0, 4> shift;
BitField<u8, u8, 4, 2> filter;

// For both 4bit and 8bit ADPCM, reserved shift values 13..15 will act same as shift=9).
u8 GetShift() const
{
const u8 shift_value = shift;
return (shift_value > 12) ? 9 : shift_value;
}

u8 GetFilter() const { return filter; }
};
static_assert(sizeof(XA_ADPCMBlockHeader) == 1, "XA-ADPCM block header is one byte");

} // namespace

static void SoftReset(TickCount ticks_late);
Expand Down Expand Up @@ -290,6 +348,9 @@ static void ResetAudioDecoder();
static void ClearSectorBuffers();
static void CheckForSectorBufferReadComplete();

// Decodes XA-ADPCM samples in an audio sector. Stereo samples are interleaved with left first.
template<bool IS_STEREO, bool IS_8BIT>
static void DecodeXAADPCMChunks(const u8* chunk_ptr, s16* samples);
template<bool STEREO, bool SAMPLE_RATE>
static void ResampleXAADPCM(const s16* frames_in, u32 num_frames_in);

Expand Down Expand Up @@ -343,7 +404,7 @@ static u8 s_xa_current_channel_number = 0;
static u8 s_xa_current_set = false;

static CDImage::SectorHeader s_last_sector_header{};
static CDXA::XASubHeader s_last_sector_subheader{};
static XASubHeader s_last_sector_subheader{};
static bool s_last_sector_header_valid = false; // TODO: Rename to "logical pause" or something.
static CDImage::SubChannelQ s_last_subq{};
static u8 s_last_cdda_report_frame_nibble = 0xFF;
Expand Down Expand Up @@ -3047,6 +3108,12 @@ ALWAYS_INLINE_RELEASE void CDROM::ProcessDataSector(const u8* raw_sector, const
SetAsyncInterrupt(Interrupt::DataReady);
}

static constexpr std::array<s8, 16> s_xa_adpcm_filter_table_pos = {
{0, 60, 115, 98, 122, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}};

static constexpr std::array<s8, 16> s_xa_adpcm_filter_table_neg = {
{0, 0, -52, -55, -60, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}};

static std::array<std::array<s16, 29>, 7> s_zigzag_table = {
{{0, 0x0, 0x0, 0x0, 0x0, -0x0002, 0x000A, -0x0022, 0x0041, -0x0054,
0x0034, 0x0009, -0x010A, 0x0400, -0x0A78, 0x234C, 0x6794, -0x1780, 0x0BCD, -0x0623,
Expand Down Expand Up @@ -3106,17 +3173,67 @@ s16 CDROM::SaturateVolume(s32 volume)
return static_cast<s16>((volume < -0x8000) ? -0x8000 : ((volume > 0x7FFF) ? 0x7FFF : volume));
}

template<bool STEREO, bool SAMPLE_RATE>
void CDROM::ResampleXAADPCM(const s16* frames_in, u32 num_frames_in)
template<bool IS_STEREO, bool IS_8BIT>
void CDROM::DecodeXAADPCMChunks(const u8* chunk_ptr, s16* samples)
{
// Since the disc reads and SPU are running at different speeds, we might be _slightly_ behind, which is fine, since
// the SPU will over-read in the next batch to catch up.
if (s_audio_fifo.GetSize() > AUDIO_FIFO_LOW_WATERMARK)
// The data layout is annoying here. Each word of data is interleaved with the other blocks, requiring multiple
// passes to decode the whole chunk.
constexpr u32 NUM_CHUNKS = 18;
constexpr u32 CHUNK_SIZE_IN_BYTES = 128;
constexpr u32 WORDS_PER_CHUNK = 28;
constexpr u32 SAMPLES_PER_CHUNK = WORDS_PER_CHUNK * (IS_8BIT ? 4 : 8);
constexpr u32 NUM_BLOCKS = IS_8BIT ? 4 : 8;
constexpr u32 WORDS_PER_BLOCK = 28;

for (u32 i = 0; i < NUM_CHUNKS; i++)
{
DEV_LOG("Dropping {} XA frames because audio FIFO still has {} frames", num_frames_in, s_audio_fifo.GetSize());
return;
const u8* headers_ptr = chunk_ptr + 4;
const u8* words_ptr = chunk_ptr + 16;

for (u32 block = 0; block < NUM_BLOCKS; block++)
{
const XA_ADPCMBlockHeader block_header{headers_ptr[block]};
const u8 shift = block_header.GetShift();
const u8 filter = block_header.GetFilter();
const s32 filter_pos = s_xa_adpcm_filter_table_pos[filter];
const s32 filter_neg = s_xa_adpcm_filter_table_neg[filter];

s16* out_samples_ptr =
IS_STEREO ? &samples[(block / 2) * (WORDS_PER_BLOCK * 2) + (block % 2)] : &samples[block * WORDS_PER_BLOCK];
constexpr u32 out_samples_increment = IS_STEREO ? 2 : 1;

for (u32 word = 0; word < 28; word++)
{
// NOTE: assumes LE
u32 word_data;
std::memcpy(&word_data, &words_ptr[word * sizeof(u32)], sizeof(word_data));

// extract nibble from block
const u32 nibble = IS_8BIT ? ((word_data >> (block * 8)) & 0xFF) : ((word_data >> (block * 4)) & 0x0F);
const s16 sample = static_cast<s16>(Truncate16(nibble << (IS_8BIT ? 8 : 12))) >> shift;

// mix in previous values
s32* prev = IS_STEREO ? &s_xa_last_samples[(block & 1) * 2] : &s_xa_last_samples[0];
const s32 interp_sample = std::clamp<s32>(
static_cast<s32>(sample) + ((prev[0] * filter_pos) >> 6) + ((prev[1] * filter_neg) >> 6), -32767, 32768);

// update previous values
prev[1] = prev[0];
prev[0] = interp_sample;

*out_samples_ptr = static_cast<s16>(interp_sample);
out_samples_ptr += out_samples_increment;
}
}

samples += SAMPLES_PER_CHUNK;
chunk_ptr += CHUNK_SIZE_IN_BYTES;
}
}

template<bool STEREO, bool SAMPLE_RATE>
void CDROM::ResampleXAADPCM(const s16* frames_in, u32 num_frames_in)
{
s16* left_ringbuf = s_xa_resample_ring_buffer[0].data();
s16* right_ringbuf = s_xa_resample_ring_buffer[1].data();
u8 p = s_xa_resample_p;
Expand Down Expand Up @@ -3219,30 +3336,58 @@ ALWAYS_INLINE_RELEASE void CDROM::ProcessXAADPCMSector(const u8* raw_sector, con
if (s_last_sector_subheader.submode.eof)
ResetCurrentXAFile();

std::array<s16, CDXA::XA_ADPCM_SAMPLES_PER_SECTOR_4BIT> sample_buffer;
CDXA::DecodeADPCMSector(raw_sector, sample_buffer.data(), s_xa_last_samples.data());
// Ensure the SPU is caught up for the test below.
SPU::GeneratePendingSamples();

// Since the disc reads and SPU are running at different speeds, we might be _slightly_ behind, which is fine, since
// the SPU will over-read in the next batch to catch up. We also should not process the sector, because it'll affect
// the previous samples used for interpolation/ADPCM. Not doing so causes crackling audio in Simple 1500 Series Vol.
// 92 - The Tozan RPG - Ginrei no Hasha (Japan).
const u32 num_frames = s_last_sector_subheader.codinginfo.GetSamplesPerSector() >>
BoolToUInt8(s_last_sector_subheader.codinginfo.IsStereo());
if (s_audio_fifo.GetSize() > AUDIO_FIFO_LOW_WATERMARK)
{
DEV_LOG("Dropping {} XA frames because audio FIFO still has {} frames", num_frames, s_audio_fifo.GetSize());
return;
}

// If muted, we still need to decode the data, to update the previous samples.
std::array<s16, XA_ADPCM_SAMPLES_PER_SECTOR_4BIT> sample_buffer;
const u8* xa_block_start =
raw_sector + CDImage::SECTOR_SYNC_SIZE + sizeof(CDImage::SectorHeader) + sizeof(XASubHeader) * 2;

if (s_last_sector_subheader.codinginfo.Is8BitADPCM())
{
if (s_last_sector_subheader.codinginfo.IsStereo())
DecodeXAADPCMChunks<true, true>(xa_block_start, sample_buffer.data());
else
DecodeXAADPCMChunks<false, true>(xa_block_start, sample_buffer.data());
}
else
{
if (s_last_sector_subheader.codinginfo.IsStereo())
DecodeXAADPCMChunks<true, false>(xa_block_start, sample_buffer.data());
else
DecodeXAADPCMChunks<false, false>(xa_block_start, sample_buffer.data());
}

// Only send to SPU if we're not muted.
if (s_muted || s_adpcm_muted || g_settings.cdrom_mute_cd_audio)
return;

SPU::GeneratePendingSamples();

if (s_last_sector_subheader.codinginfo.IsStereo())
{
const u32 num_samples = s_last_sector_subheader.codinginfo.GetSamplesPerSector() / 2;
if (s_last_sector_subheader.codinginfo.IsHalfSampleRate())
ResampleXAADPCM<true, true>(sample_buffer.data(), num_samples);
ResampleXAADPCM<true, true>(sample_buffer.data(), num_frames);
else
ResampleXAADPCM<true, false>(sample_buffer.data(), num_samples);
ResampleXAADPCM<true, false>(sample_buffer.data(), num_frames);
}
else
{
const u32 num_samples = s_last_sector_subheader.codinginfo.GetSamplesPerSector();
if (s_last_sector_subheader.codinginfo.IsHalfSampleRate())
ResampleXAADPCM<false, true>(sample_buffer.data(), num_samples);
ResampleXAADPCM<false, true>(sample_buffer.data(), num_frames);
else
ResampleXAADPCM<false, false>(sample_buffer.data(), num_samples);
ResampleXAADPCM<false, false>(sample_buffer.data(), num_frames);
}
}

Expand Down
2 changes: 0 additions & 2 deletions src/util/CMakeLists.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -17,8 +17,6 @@ add_library(util
cd_image_ppf.cpp
cd_subchannel_replacement.cpp
cd_subchannel_replacement.h
cd_xa.cpp
cd_xa.h
cue_parser.cpp
cue_parser.h
gpu_device.cpp
Expand Down
102 changes: 0 additions & 102 deletions src/util/cd_xa.cpp
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