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cog/Frameworks/vgmstream/vgmstream/src/coding/relic_decoder.c

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#include "coding.h"
/* Relic Codec decoder, a fairly simple mono-interleave DCT-based codec.
*
* Decompiled from Relic's dec.exe with some info from Homeworld source code .h/lib
* files (released around 2003 through Relic Dev Network), accurate with minor +-1
* samples due to double<>float ops or maybe original compiler (Intel's) diffs.
*
* TODO: clean API, improve validations (can segfault on bad data) and naming
*/
/* mixfft.c */
extern void fft(int n, float *xRe, float *xIm, float *yRe, float *yIm);
static relic_codec_data* init_codec(int channels, int bitrate, int codec_rate);
static int decode_frame_next(VGMSTREAMCHANNEL* stream, relic_codec_data* data);
static void copy_samples(relic_codec_data* data, sample_t* outbuf, int32_t samples_to_get);
static void reset_codec(relic_codec_data* data);
#define RELIC_MAX_CHANNELS 2
#define RELIC_MAX_SCALES 6
#define RELIC_BASE_SCALE 10.0f
#define RELIC_FREQUENCY_MASKING_FACTOR 1.0f
#define RELIC_CRITICAL_BAND_COUNT 27
#define RELIC_PI 3.14159265358979323846f
#define RELIC_SIZE_LOW 128
#define RELIC_SIZE_MID 256
#define RELIC_SIZE_HIGH 512
#define RELIC_MAX_SIZE RELIC_SIZE_HIGH
#define RELIC_MAX_FREQ (RELIC_MAX_SIZE / 2)
#define RELIC_MAX_FFT (RELIC_MAX_SIZE / 4)
#define RELIC_BITRATE_22 256
#define RELIC_BITRATE_44 512
#define RELIC_BITRATE_88 1024
#define RELIC_BITRATE_176 2048
#define RELIC_MAX_FRAME_SIZE ((RELIC_BITRATE_176 / 8) + 0x04) /* extra 0x04 for the bitreader */
struct relic_codec_data {
/* decoder info */
int channels;
int frame_size;
int wave_size;
int freq_size;
int dct_mode;
int samples_mode;
/* decoder init state */
float scales[RELIC_MAX_SCALES]; /* quantization scales */
float dct[RELIC_MAX_SIZE];
float window[RELIC_MAX_SIZE];
/* decoder frame state */
uint8_t exponents[RELIC_MAX_CHANNELS][RELIC_MAX_FREQ]; /* quantization/scale indexes */
float freq1[RELIC_MAX_FREQ]; /* dequantized spectrum */
float freq2[RELIC_MAX_FREQ];
float wave_cur[RELIC_MAX_CHANNELS][RELIC_MAX_SIZE]; /* current frame samples */
float wave_prv[RELIC_MAX_CHANNELS][RELIC_MAX_SIZE]; /* previous frame samples */
/* sample state */
int32_t samples_discard;
int32_t samples_consumed;
int32_t samples_filled;
};
/* ************************************* */
relic_codec_data* init_relic(int channels, int bitrate, int codec_rate) {
return init_codec(channels, bitrate, codec_rate);
}
void decode_relic(VGMSTREAMCHANNEL* stream, relic_codec_data* data, sample_t* outbuf, int32_t samples_to_do) {
while (samples_to_do > 0) {
if (data->samples_consumed < data->samples_filled) {
/* consume samples */
int samples_to_get = (data->samples_filled - data->samples_consumed);
if (data->samples_discard) {
/* discard samples for looping */
if (samples_to_get > data->samples_discard)
samples_to_get = data->samples_discard;
data->samples_discard -= samples_to_get;
}
else {
/* get max samples and copy */
if (samples_to_get > samples_to_do)
samples_to_get = samples_to_do;
copy_samples(data, outbuf, samples_to_get);
samples_to_do -= samples_to_get;
outbuf += samples_to_get * data->channels;
}
/* mark consumed samples */
data->samples_consumed += samples_to_get;
}
else {
int ok = decode_frame_next(stream, data);
if (!ok) goto decode_fail;
}
}
return;
decode_fail:
/* on error just put some 0 samples */
VGM_LOG("RELIC: decode fail, missing %i samples\n", samples_to_do);
memset(outbuf, 0, samples_to_do * data->channels * sizeof(sample));
}
void reset_relic(relic_codec_data* data) {
if (!data) return;
reset_codec(data);
data->samples_filled = 0;
data->samples_consumed = 0;
data->samples_discard = 0;
}
void seek_relic(relic_codec_data* data, int32_t num_sample) {
if (!data) return;
reset_relic(data);
data->samples_discard = num_sample;
}
void free_relic(relic_codec_data* data) {
if (!data) return;
free(data);
}
/* ***************************************** */
static const int16_t critical_band_data[RELIC_CRITICAL_BAND_COUNT] = {
0, 1, 2, 3, 4, 5, 6, 7,
9, 11, 13, 15, 17, 20, 23, 27,
31, 37, 43, 51, 62, 74, 89, 110,
139, 180, 256
};
static void init_dct(float *dct, int dct_size) {
int i;
int dct_quarter = dct_size >> 2;
for (i = 0; i < dct_quarter; i++) {
double temp = ((float)i + 0.125f) * (RELIC_PI * 2.0f) * (1.0f / (float)dct_size);
dct[i] = sin(temp);
dct[dct_quarter + i] = cos(temp);
}
}
static int apply_idct(const float *freq, float *wave, const float *dct, int dct_size) {
int i;
float factor;
float out_re[RELIC_MAX_FFT];
float out_im[RELIC_MAX_FFT];
float in_re[RELIC_MAX_FFT];
float in_im[RELIC_MAX_FFT];
float wave_tmp[RELIC_MAX_SIZE];
int dct_half = dct_size >> 1;
int dct_quarter = dct_size >> 2;
int dct_3quarter = 3 * (dct_size >> 2);
/* prerotation? */
for (i = 0; i < dct_quarter; i++) {
float coef1 = freq[2 * i] * 0.5f;
float coef2 = freq[dct_half - 1 - 2 * i] * 0.5f;
in_re[i] = coef1 * dct[dct_quarter + i] + coef2 * dct[i];
in_im[i] = -coef1 * dct[i] + coef2 * dct[dct_quarter + i];
}
/* main FFT */
fft(dct_quarter, in_re, in_im, out_re, out_im);
/* postrotation, window and reorder? */
factor = 8.0 / sqrt(dct_size);
for (i = 0; i < dct_quarter; i++) {
float out_re_i = out_re[i];
out_re[i] = (out_re[i] * dct[dct_quarter + i] + out_im[i] * dct[i]) * factor;
out_im[i] = (-out_re_i * dct[i] + out_im[i] * dct[dct_quarter + i]) * factor;
wave_tmp[i * 2] = out_re[i];
wave_tmp[i * 2 + dct_half] = out_im[i];
}
for (i = 1; i < dct_size; i += 2) {
wave_tmp[i] = -wave_tmp[dct_size - 1 - i];
}
/* wave mix thing? */
for (i = 0; i < dct_3quarter; i++) {
wave[i] = wave_tmp[dct_quarter + i];
}
for (i = dct_3quarter; i < dct_size; i++) {
wave[i] = -wave_tmp[i - dct_3quarter];
}
return 0;
}
static void decode_frame(const float *freq1, const float *freq2, float *wave_cur, float *wave_prv, const float *dct, const float *window, int dct_size) {
int i;
float wave_tmp[RELIC_MAX_SIZE];
int dct_half = dct_size >> 1;
/* copy for first half(?) */
memcpy(wave_cur, wave_prv, RELIC_MAX_SIZE * sizeof(float));
/* transform frequency domain to time domain with DCT/FFT */
apply_idct(freq1, wave_tmp, dct, dct_size);
apply_idct(freq2, wave_prv, dct, dct_size);
/* overlap and apply window function to filter this block's beginning */
for (i = 0; i < dct_half; i++) {
wave_cur[dct_half + i] = wave_tmp[i] * window[i] + wave_cur[dct_half + i] * window[dct_half + i];
wave_prv[i] = wave_prv[i] * window[i] + wave_tmp[dct_half + i] * window[dct_half + i];
}
}
static void init_window(float *window, int dct_size) {
int i;
for (i = 0; i < dct_size; i++) {
window[i] = sin((float)i * (RELIC_PI / dct_size));
}
}
static void decode_frame_base(const float *freq1, const float *freq2, float *wave_cur, float *wave_prv, const float *dct, const float *window, int dct_mode, int samples_mode) {
int i;
float wave_tmp[RELIC_MAX_SIZE];
/* dec_relic only uses 512/512 mode, source references 256/256 (effects only?) too */
if (samples_mode == RELIC_SIZE_LOW) {
{
/* 128 DCT to 128 samples */
decode_frame(freq1, freq2, wave_cur, wave_prv, dct, window, RELIC_SIZE_LOW);
}
}
else if (samples_mode == RELIC_SIZE_MID) {
if (dct_mode == RELIC_SIZE_LOW) {
/* 128 DCT to 256 samples (repeat sample x2) */
decode_frame(freq1, freq2, wave_tmp, wave_prv, dct, window, RELIC_SIZE_LOW);
for (i = 0; i < 256 - 1; i += 2) {
wave_cur[i + 0] = wave_tmp[i >> 1];
wave_cur[i + 1] = wave_tmp[i >> 1];
}
}
else {
/* 256 DCT to 256 samples */
decode_frame(freq1, freq2, wave_cur, wave_prv, dct, window, RELIC_SIZE_MID);
}
}
else if (samples_mode == RELIC_SIZE_HIGH) {
if (dct_mode == RELIC_SIZE_LOW) {
/* 128 DCT to 512 samples (repeat sample x4) */
decode_frame(freq1, freq2, wave_tmp, wave_prv, dct, window, RELIC_SIZE_LOW);
for (i = 0; i < 512 - 1; i += 4) {
wave_cur[i + 0] = wave_tmp[i >> 2];
wave_cur[i + 1] = wave_tmp[i >> 2];
wave_cur[i + 2] = wave_tmp[i >> 2];
wave_cur[i + 3] = wave_tmp[i >> 2];
}
}
else if (dct_mode == RELIC_SIZE_MID) {
/* 256 DCT to 512 samples (repeat sample x2) */
decode_frame(freq1, freq2, wave_tmp, wave_prv, dct, window, RELIC_SIZE_MID);
for (i = 0; i < 512 - 1; i += 2) {
wave_cur[i + 0] = wave_tmp[i >> 1];
wave_cur[i + 1] = wave_tmp[i >> 1];
}
}
else {
/* 512 DCT to 512 samples */
decode_frame(freq1, freq2, wave_cur, wave_prv, dct, window, RELIC_SIZE_HIGH);
}
}
}
/* reads 32b max, packed in LSB order per byte (like Vorbis), ex.
* with 0x45 6A=01000101 01101010 could read 4b=0101, 6b=100100, 3b=010 ...
* assumes buf has enough extra bits to read 32b (size +0x04) */
static uint32_t read_ubits(uint8_t bits, uint32_t offset, uint8_t *buf) {
uint32_t shift, mask, pos, val;
shift = offset - 8 * (offset / 8);
mask = (1 << bits) - 1;
pos = offset / 8;
val = (buf[pos+0]) | (buf[pos+1]<<8) | (buf[pos+2]<<16) | (buf[pos+3]<<24);
return (val >> shift) & mask;
}
static int read_sbits(uint8_t bits, uint32_t offset, uint8_t *buf) {
uint32_t val = read_ubits(bits, offset, buf);
if (val >> (bits - 1) == 1) { /* upper bit = sign */
uint32_t mask = (1 << (bits - 1)) - 1;
return -(val & mask);
}
return val;
}
static void init_dequantization(float* scales) {
int i;
scales[0] = RELIC_BASE_SCALE;
for (i = 1; i < RELIC_MAX_SCALES; i++) {
scales[i] = scales[i - 1] * scales[0];
}
for (i = 0; i < RELIC_MAX_SCALES; i++) {
scales[i] = RELIC_FREQUENCY_MASKING_FACTOR / (double) ((1 << (i + 1)) - 1) * scales[i];
}
}
static void unpack_frame(uint8_t *buf, int buf_size, float *freq1, float *freq2, const float* scales, uint8_t *exponents, int freq_size) {
uint8_t flags, cb_bits, ev_bits, ei_bits, qv_bits;
int qv;
uint8_t ev;
uint8_t move, pos;
uint32_t bit_offset;
int i, j;
int freq_half = freq_size >> 1;
memset(freq1, 0, RELIC_MAX_FREQ * sizeof(float));
memset(freq2, 0, RELIC_MAX_FREQ * sizeof(float));
flags = read_ubits(2u, 0u, buf);
cb_bits = read_ubits(3u, 2u, buf);
ev_bits = read_ubits(2u, 5u, buf);
ei_bits = read_ubits(4u, 7u, buf);
bit_offset = 11;
/* reset exponents indexes */
if ((flags & 1) == 1) {
memset(exponents, 0, RELIC_MAX_FREQ);
}
/* read packed exponents indexes for all bands */
if (cb_bits > 0 && ev_bits > 0) {
pos = 0;
for (i = 0; i < RELIC_CRITICAL_BAND_COUNT - 1; i++) {
if (bit_offset >= 8*buf_size)
break;
move = read_ubits(cb_bits, bit_offset, buf);
bit_offset += cb_bits;
if (i > 0 && move == 0)
break;
pos += move;
ev = read_ubits(ev_bits, bit_offset, buf);
bit_offset += ev_bits;
for (j = critical_band_data[pos]; j < critical_band_data[pos + 1]; j++)
exponents[j] = ev;
}
}
/* read quantized values */
if (freq_half > 0 && ei_bits > 0) {
/* read first part */
pos = 0;
for (i = 0; i < RELIC_MAX_FREQ; i++) {
if (bit_offset >= 8*buf_size)
break;
move = read_ubits(ei_bits, bit_offset, buf);
bit_offset += ei_bits;
if (i > 0 && move == 0)
break;
pos += move;
qv_bits = exponents[pos];
qv = read_sbits(qv_bits + 2u, bit_offset, buf);
bit_offset += qv_bits + 2u;
if (qv != 0 && pos < freq_half && qv_bits < 6)
freq1[pos] = (float)qv * scales[qv_bits];
}
/* read second part, or clone it */
if ((flags & 2) == 2) {
memcpy(freq2, freq1, RELIC_MAX_FREQ * sizeof(float));
}
else {
pos = 0;
for (i = 0; i < RELIC_MAX_FREQ; i++) {
if (bit_offset >= 8*buf_size)
break;
move = read_ubits(ei_bits, bit_offset, buf);
bit_offset += ei_bits;
if (i > 0 && move == 0)
break;
pos += move;
qv_bits = exponents[pos];
qv = read_sbits(qv_bits + 2u, bit_offset, buf);
bit_offset += qv_bits + 2u;
if (qv != 0 && pos < freq_half && qv_bits < 6)
freq2[pos] = (float)qv * scales[qv_bits];
}
}
}
}
static int decode_frame_next(VGMSTREAMCHANNEL* stream, relic_codec_data* data) {
int ch;
int bytes;
uint8_t buf[RELIC_MAX_FRAME_SIZE];
for (ch = 0; ch < data->channels; ch++) {
/* clean extra bytes for bitreader */
memset(buf + data->frame_size, 0, RELIC_MAX_FRAME_SIZE - data->frame_size);
bytes = read_streamfile(buf, stream->offset, data->frame_size, stream->streamfile);
if (bytes != data->frame_size) goto fail;
stream->offset += data->frame_size;
unpack_frame(buf, sizeof(buf), data->freq1, data->freq2, data->scales, data->exponents[ch], data->freq_size);
decode_frame_base(data->freq1, data->freq2, data->wave_cur[ch], data->wave_prv[ch], data->dct, data->window, data->dct_mode, data->samples_mode);
}
data->samples_consumed = 0;
data->samples_filled = data->wave_size;
return 1;
fail:
return 0;
}
static void copy_samples(relic_codec_data* data, sample_t* outbuf, int32_t samples) {
int s, ch;
int ichs = data->channels;
int skip = data->samples_consumed;
for (ch = 0; ch < ichs; ch++) {
for (s = 0; s < samples; s++) {
double d64_sample = data->wave_cur[ch][skip + s];
int pcm_sample = clamp16(d64_sample);
/* f32 in PCM 32767.0 .. -32768.0 format, original code
* does some custom double-to-int rint() though */
//FQ_BNUM ((float)(1<<26)*(1<<26)*1.5)
//rint(x) ((d64 = (double)(x)+FQ_BNUM), *(int*)(&d64))
outbuf[s*ichs + ch] = pcm_sample;
}
}
}
static relic_codec_data* init_codec(int channels, int bitrate, int codec_rate) {
relic_codec_data *data = NULL;
if (channels > RELIC_MAX_CHANNELS)
goto fail;
data = calloc(1, sizeof(relic_codec_data));
if (!data) goto fail;
data->channels = channels;
/* dequantized freq1+2 size (separate from DCT) */
if (codec_rate < 22050) /* probably 11025 only */
data->freq_size = RELIC_SIZE_LOW;
if (codec_rate == 22050)
data->freq_size = RELIC_SIZE_MID;
if (codec_rate > 22050) /* probably 44100 only */
data->freq_size = RELIC_SIZE_HIGH;
/* default for streams (only a few mode combos are valid, see decode) */
data->wave_size = RELIC_SIZE_HIGH;
data->dct_mode = RELIC_SIZE_HIGH;
data->samples_mode = RELIC_SIZE_HIGH;
init_dct(data->dct, RELIC_SIZE_HIGH);
init_window(data->window, RELIC_SIZE_HIGH);
init_dequantization(data->scales);
memset(data->wave_prv, 0, RELIC_MAX_CHANNELS * RELIC_MAX_SIZE * sizeof(float));
switch(bitrate) {
case RELIC_BITRATE_22:
case RELIC_BITRATE_44:
case RELIC_BITRATE_88:
case RELIC_BITRATE_176:
data->frame_size = (bitrate / 8); /* 0x100 and 0x80 are common */
break;
default:
goto fail;
}
return data;
fail:
free_relic(data);
return NULL;
}
static void reset_codec(relic_codec_data* data) {
memset(data->wave_prv, 0, RELIC_MAX_CHANNELS * RELIC_MAX_SIZE * sizeof(float));
}
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