65 lines
2.0 KiB
C
65 lines
2.0 KiB
C
#include "coding.h"
|
|
#include "../util.h"
|
|
|
|
/* standard XA/PSX coefs << 6 */
|
|
static const int8_t proc_coefs[16][2] = {
|
|
{ 0, 0 },
|
|
{ 60, 0 },
|
|
{ 115, -52 },
|
|
{ 98, -55 },
|
|
{ 122, -60 },
|
|
/* rest is 0s */
|
|
};
|
|
|
|
/* ADPCM found in NDS games using Procyon Studio Digital Sound Elements */
|
|
void decode_nds_procyon(VGMSTREAMCHANNEL *stream, sample_t *outbuf, int channelspacing, int32_t first_sample, int32_t samples_to_do) {
|
|
uint8_t frame[0x10] = {0};
|
|
off_t frame_offset;
|
|
int i, frames_in, sample_count = 0;
|
|
size_t bytes_per_frame, samples_per_frame;
|
|
int index, scale, coef1, coef2;
|
|
int32_t hist1 = stream->adpcm_history1_32;
|
|
int32_t hist2 = stream->adpcm_history2_32;
|
|
uint8_t header;
|
|
|
|
|
|
/* external interleave (fixed size), mono */
|
|
bytes_per_frame = 0x10;
|
|
samples_per_frame = (bytes_per_frame - 0x01) * 2; /* 30 */
|
|
frames_in = first_sample / samples_per_frame;
|
|
|
|
/* parse frame header */
|
|
frame_offset = stream->offset + bytes_per_frame * frames_in;
|
|
read_streamfile(frame, frame_offset, bytes_per_frame, stream->streamfile); /* ignore EOF errors */
|
|
header = frame[0x0F] ^ 0x80;
|
|
scale = 12 - (header & 0xf);
|
|
index = (header >> 4) & 0xf;
|
|
coef1 = proc_coefs[index][0];
|
|
coef2 = proc_coefs[index][1];
|
|
|
|
/* decode nibbles */
|
|
for (i = first_sample; i < first_sample + samples_to_do; i++) {
|
|
uint8_t nibbles = frame[i/2] ^ 0x80;
|
|
int32_t sample = 0;
|
|
|
|
sample = i&1 ? /* low nibble first */
|
|
get_high_nibble_signed(nibbles) :
|
|
get_low_nibble_signed(nibbles);
|
|
sample = sample * 64 * 64; /* << 12 */
|
|
if (scale < 0)
|
|
sample <<= -scale;
|
|
else
|
|
sample >>= scale;
|
|
sample = (hist1 * coef1 + hist2 * coef2 + 32) / 64 + (sample * 64);
|
|
|
|
hist2 = hist1;
|
|
hist1 = sample; /* clamp *after* this */
|
|
|
|
outbuf[sample_count] = clamp16((sample + 32) / 64) / 64 * 64;
|
|
sample_count += channelspacing;
|
|
}
|
|
|
|
stream->adpcm_history1_32 = hist1;
|
|
stream->adpcm_history2_32 = hist2;
|
|
}
|