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neotools: neoadpcmextract now converts ADPCM-B to Wave

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a dinosaur
2023-12-29 04:04:28 +11:00
parent 5b28c18472
commit 47f6b23943
4 changed files with 133 additions and 101 deletions
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92
neotools/libadpcmb.c Normal file
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/* libadpcmb.c (C) 2023 a dinosaur (zlib)
** YM2610 ADPCM-B Codec **
PCM to ADPCM-B & ADPCM-B to PCM converters for NEO-GEO System
ADPCM-B - 1 channel 1.8-55.5 KHz, 16 MB Sample ROM size,
256 B min size of sample, 16 MB max, compatable with YM2608
http://www.raregame.ru/file/15/YM2610.pdf YM2610 DATASHEET
*/
#include "adpcmb.h"
#include "util.h"
#include <stdlib.h>
static const long stepSizeTable[16] =
{
57, 57, 57, 57, 77, 102, 128, 153,
57, 57, 57, 57, 77, 102, 128, 153
};
void adpcmBEncoderInit(AdpcmBEncoderState* encoder)
{
encoder->xn = 0;
encoder->stepSize = 127;
encoder->flag = false;
encoder->adpcmPack = 0;
}
void adpcmBEncode(AdpcmBEncoderState* encoder, const int16_t* restrict in, uint8_t* restrict out, int len)
{
for (int lpc = 0; lpc < len; ++lpc)
{
long dn = (*in++) - encoder->xn;
long i = (labs(dn) << 16) / (encoder->stepSize << 14);
i = MIN(i, 7);
uint8_t adpcm = i;
i = (adpcm * 2 + 1) * encoder->stepSize / 8;
if (dn < 0)
{
adpcm |= 0x8;
encoder->xn -= i;
}
else
{
encoder->xn += i;
}
encoder->stepSize = (stepSizeTable[adpcm] * encoder->stepSize) / 64;
encoder->stepSize = CLAMP(encoder->stepSize, 127, 24576);
if (!encoder->flag)
{
encoder->adpcmPack = adpcm << 4;
encoder->flag = true;
}
else
{
(*out++) = encoder->adpcmPack |= adpcm;
encoder->flag = false;
}
}
}
void adpcmBDecoderInit(AdpcmBDecoderState* decoder)
{
decoder->xn = 0;
decoder->stepSize = 127;
}
void adpcmBDecode(AdpcmBDecoderState* decoder, const uint8_t* restrict in, int16_t* restrict out, int len)
{
for (long lpc = 0; lpc < len * 2; ++lpc)
{
uint8_t adpcm = (!(lpc & 0x1) ? (*in) >> 4 : (*in++)) & 0xF;
long i = ((adpcm & 7) * 2 + 1) * decoder->stepSize / 8;
if (adpcm & 8)
decoder->xn -= i;
else
decoder->xn += i;
decoder->xn = CLAMP(decoder->xn, -32768, 32767);
decoder->stepSize = decoder->stepSize * stepSizeTable[adpcm] / 64;
decoder->stepSize = CLAMP(decoder->stepSize, 127, 24576);
(*out++) = (int16_t)decoder->xn;
}
}