vgmstream/src/coding/psx_decoder.c
2017-05-01 16:58:33 +02:00

237 lines
7.3 KiB
C

#include <math.h>
#include "coding.h"
#include "../util.h"
/* for some algos, maybe closer to the real thing */
#define VAG_USE_INTEGER_TABLE 0
/* PS ADPCM table (precalculated divs) */
static const double VAG_f[5][2] = {
{ 0.0 , 0.0 },
{ 60.0 / 64.0 , 0.0 },
{ 115.0 / 64.0 , -52.0 / 64.0 },
{ 98.0 / 64.0 , -55.0 / 64.0 },
{ 122.0 / 64.0 , -60.0 / 64.0 }
};
#if VAG_USE_INTEGER_TABLE
/* PS ADPCM table */
static const int8_t VAG_coefs[5][2] = {
{ 0 , 0 },
{ 60 , 0 },
{ 115 , -52 },
{ 98 , -55 },
{ 122 , -60 }
};
#endif
/**
* Sony's PS ADPCM (sometimes called VAG), decodes 16 bytes into 28 samples.
* The first 2 bytes are a header (shift, predictor, optional flag).
* All variants are the same with minor differences.
*
* Flags:
* 0x0: Nothing
* 0x1: End marker + decode
* 0x2: Loop region
* 0x3: Loop end
* 0x4: Start marker
* 0x5: ?
* 0x6: Loop start
* 0x7: End marker + don't decode
* 0x8+ Not valid
*/
/* default */
void decode_psx(VGMSTREAMCHANNEL * stream, sample * outbuf, int channelspacing, int32_t first_sample, int32_t samples_to_do) {
int predict_nr, shift_factor, sample;
int32_t hist1=stream->adpcm_history1_32;
int32_t hist2=stream->adpcm_history2_32;
short scale;
int i;
int32_t sample_count;
uint8_t flag;
int framesin = first_sample/28;
predict_nr = read_8bit(stream->offset+framesin*16,stream->streamfile) >> 4;
shift_factor = read_8bit(stream->offset+framesin*16,stream->streamfile) & 0xf;
flag = read_8bit(stream->offset+framesin*16+1,stream->streamfile); /* only lower nibble needed */
first_sample = first_sample % 28;
for (i=first_sample,sample_count=0; i<first_sample+samples_to_do; i++,sample_count+=channelspacing) {
sample=0;
if(flag<0x07) {
short sample_byte = (short)read_8bit(stream->offset+(framesin*16)+2+i/2,stream->streamfile);
scale = ((i&1 ? /* odd/even byte */
sample_byte >> 4 :
sample_byte & 0x0f)<<12);
sample=(int)((scale >> shift_factor)+hist1*VAG_f[predict_nr][0]+hist2*VAG_f[predict_nr][1]);
}
outbuf[sample_count] = clamp16(sample);
hist2=hist1;
hist1=sample;
}
stream->adpcm_history1_32=hist1;
stream->adpcm_history2_32=hist2;
}
/* encrypted */
void decode_psx_bmdx(VGMSTREAMCHANNEL * stream, sample * outbuf, int channelspacing, int32_t first_sample, int32_t samples_to_do) {
int predict_nr, shift_factor, sample;
int32_t hist1=stream->adpcm_history1_32;
int32_t hist2=stream->adpcm_history2_32;
short scale;
int i;
int32_t sample_count;
uint8_t flag;
int framesin = first_sample/28;
int head = read_8bit(stream->offset+framesin*16,stream->streamfile) ^ stream->bmdx_xor;
predict_nr = ((head >> 4) & 0xf);
shift_factor = (head & 0xf);
flag = read_8bit(stream->offset+framesin*16+1,stream->streamfile);
first_sample = first_sample % 28;
for (i=first_sample,sample_count=0; i<first_sample+samples_to_do; i++,sample_count+=channelspacing) {
sample=0;
if(flag<0x07) {
short sample_byte = (short)read_8bit(stream->offset+(framesin*16)+2+i/2,stream->streamfile);
if (i/2 == 0)
sample_byte = (short)(int8_t)(sample_byte+stream->bmdx_add);
scale = ((i&1 ?
sample_byte >> 4 :
sample_byte & 0x0f)<<12);
sample=(int)((scale >> shift_factor)+hist1*VAG_f[predict_nr][0]+hist2*VAG_f[predict_nr][1]);
}
outbuf[sample_count] = clamp16(sample);
hist2=hist1;
hist1=sample;
}
stream->adpcm_history1_32=hist1;
stream->adpcm_history2_32=hist2;
}
/* some games have garbage (?) in their flags, this decoder just ignores that byte */
void decode_psx_badflags(VGMSTREAMCHANNEL * stream, sample * outbuf, int channelspacing, int32_t first_sample, int32_t samples_to_do) {
int predict_nr, shift_factor, sample;
int32_t hist1=stream->adpcm_history1_32;
int32_t hist2=stream->adpcm_history2_32;
short scale;
int i;
int32_t sample_count;
int framesin = first_sample/28;
predict_nr = read_8bit(stream->offset+framesin*16,stream->streamfile) >> 4;
shift_factor = read_8bit(stream->offset+framesin*16,stream->streamfile) & 0xf;
first_sample = first_sample % 28;
for (i=first_sample,sample_count=0; i<first_sample+samples_to_do; i++,sample_count+=channelspacing) {
short sample_byte = (short)read_8bit(stream->offset+(framesin*16)+2+i/2,stream->streamfile);
scale = ((i&1 ?
sample_byte >> 4 :
sample_byte & 0x0f)<<12);
sample=(int)((scale >> shift_factor)+hist1*VAG_f[predict_nr][0]+hist2*VAG_f[predict_nr][1]);
outbuf[sample_count] = clamp16(sample);
hist2=hist1;
hist1=sample;
}
stream->adpcm_history1_32=hist1;
stream->adpcm_history2_32=hist2;
}
/* configurable frame size, with no flag
* Found in PS3 Afrika (SGXD type 5) in size 4, FF XI in sizes 3/5/9/41, Blur and James Bond in size 33. */
void decode_psx_configurable(VGMSTREAMCHANNEL * stream, sample * outbuf, int channelspacing, int32_t first_sample, int32_t samples_to_do, int frame_size) {
uint8_t predict_nr, shift, byte;
int16_t scale = 0;
int32_t sample;
int32_t hist1 = stream->adpcm_history1_32;
int32_t hist2 = stream->adpcm_history2_32;
int i, sample_count, bytes_per_frame, samples_per_frame;
const int header_size = 1;
int framesin;
bytes_per_frame = frame_size - header_size;
samples_per_frame = bytes_per_frame * 2;
framesin = first_sample / samples_per_frame;
/* 1 byte header: predictor = 1st, shift = 2nd */
byte = (uint8_t)read_8bit(stream->offset+framesin*frame_size+0,stream->streamfile);
predict_nr = byte >> 4;
shift = byte & 0x0f;
first_sample = first_sample % samples_per_frame;
if (first_sample & 1) { /* if restarting on a high nibble, read byte first */
byte = (uint8_t)read_8bit(stream->offset+(framesin*frame_size)+header_size+first_sample/2,stream->streamfile);
}
for (i = first_sample, sample_count = 0; i < first_sample + samples_to_do; i++, sample_count += channelspacing) {
sample = 0;
if (predict_nr < 5) {
if (!(i&1)) { /* low nibble first */
byte = (uint8_t)read_8bit(stream->offset+(framesin*frame_size)+header_size+i/2,stream->streamfile);
scale = (byte & 0x0f);
} else { /* high nibble last */
scale = byte >> 4;
}
scale = scale << 12; /* shift + sign extend (only if scale is int16_t) */
/*if (scale > 7) {
scale = scale - 16;
}*/
#if VAG_USE_INTEGER_TABLE
sample = (scale >> shift) +
(hist1 * VAG_coefs[predict_nr][0] +
hist2 * VAG_coefs[predict_nr][1] ) / 64;
#else
sample = (int)( (scale >> shift) +
(hist1 * VAG_f[predict_nr][0] +
hist2 * VAG_f[predict_nr][1]) );
#endif
}
outbuf[sample_count] = clamp16(sample);
hist2 = hist1;
hist1 = sample;
}
stream->adpcm_history1_32 = hist1;
stream->adpcm_history2_32 = hist2;
}
size_t ps_bytes_to_samples(size_t bytes, int channels) {
return bytes / channels / 16 * 28;
}