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//============================================
//=== Audio XA decoding
//=== Kazzuya
//============================================
//=== Modified by linuzappz
//============================================
#include <stdio.h>
#include "Decode_XA.h"
#ifdef __WIN32__
#pragma warning(disable:4244)
#endif
typedef unsigned char U8;
typedef unsigned short U16;
typedef unsigned long U32;
#define NOT(_X_) (!(_X_))
#define CLAMP(_X_,_MI_,_MA_) {if(_X_<_MI_)_X_=_MI_;if(_X_>_MA_)_X_=_MA_;}
//============================================
//=== ADPCM DECODING ROUTINES
//============================================
static double K0[4] = {
0.0,
0.9375,
1.796875,
1.53125
};
static double K1[4] = {
0.0,
0.0,
-0.8125,
-0.859375
};
#define BLKSIZ 28 /* block size (32 - 4 nibbles) */
//===========================================
void ADPCM_InitDecode( ADPCM_Decode_t *decp )
{
decp->y0 = 0;
decp->y1 = 0;
}
//===========================================
#define SH 4
#define SHC 10
#define IK0(fid) ((int)((-K0[fid]) * (1<<SHC)))
#define IK1(fid) ((int)((-K1[fid]) * (1<<SHC)))
void ADPCM_DecodeBlock16( ADPCM_Decode_t *decp, U8 filter_range, const void *vblockp, short *destp, int inc ) {
int i;
int range, filterid;
long fy0, fy1;
const U16 *blockp;
blockp = (const unsigned short *)vblockp;
filterid = (filter_range >> 4) & 0x0f;
range = (filter_range >> 0) & 0x0f;
fy0 = decp->y0;
fy1 = decp->y1;
for (i = BLKSIZ/4; i; --i) {
long y;
long x0, x1, x2, x3;
y = *blockp++;
x3 = (short)( y & 0xf000) >> range; x3 <<= SH;
x2 = (short)((y << 4) & 0xf000) >> range; x2 <<= SH;
x1 = (short)((y << 8) & 0xf000) >> range; x1 <<= SH;
x0 = (short)((y << 12) & 0xf000) >> range; x0 <<= SH;
x0 -= (IK0(filterid) * fy0 + (IK1(filterid) * fy1)) >> SHC; fy1 = fy0; fy0 = x0;
x1 -= (IK0(filterid) * fy0 + (IK1(filterid) * fy1)) >> SHC; fy1 = fy0; fy0 = x1;
x2 -= (IK0(filterid) * fy0 + (IK1(filterid) * fy1)) >> SHC; fy1 = fy0; fy0 = x2;
x3 -= (IK0(filterid) * fy0 + (IK1(filterid) * fy1)) >> SHC; fy1 = fy0; fy0 = x3;
CLAMP( x0, -32768<<SH, 32767<<SH ); *destp = x0 >> SH; destp += inc;
CLAMP( x1, -32768<<SH, 32767<<SH ); *destp = x1 >> SH; destp += inc;
CLAMP( x2, -32768<<SH, 32767<<SH ); *destp = x2 >> SH; destp += inc;
CLAMP( x3, -32768<<SH, 32767<<SH ); *destp = x3 >> SH; destp += inc;
}
decp->y0 = fy0;
decp->y1 = fy1;
}
static int headtable[4] = {0,2,8,10};
//===========================================
static void xa_decode_data( xa_decode_t *xdp, unsigned char *srcp ) {
const U8 *sound_groupsp;
const U8 *sound_datap, *sound_datap2;
int i, j, k, nbits;
U16 data[4096], *datap;
short *destp;
destp = xdp->pcm;
nbits = xdp->nbits == 4 ? 4 : 2;
if (xdp->stereo) { // stereo
for (j=0; j < 18; j++) {
sound_groupsp = srcp + j * 128; // sound groups header
sound_datap = sound_groupsp + 16; // sound data just after the header
for (i=0; i < nbits; i++) {
datap = data;
sound_datap2 = sound_datap + i;
if ((xdp->nbits == 8) && (xdp->freq == 37800)) { // level A
for (k=0; k < 14; k++, sound_datap2 += 8) {
*(datap++) = (U16)sound_datap2[0] |
(U16)(sound_datap2[4] << 8);
}
} else { // level B/C
for (k=0; k < 7; k++, sound_datap2 += 16) {
*(datap++) = (U16)(sound_datap2[ 0] & 0x0f) |
((U16)(sound_datap2[ 4] & 0x0f) << 4) |
((U16)(sound_datap2[ 8] & 0x0f) << 8) |
((U16)(sound_datap2[12] & 0x0f) << 12);
}
}
ADPCM_DecodeBlock16( &xdp->left, sound_groupsp[headtable[i]+0], data,
destp+0, 2 );
datap = data;
sound_datap2 = sound_datap + i;
if ((xdp->nbits == 8) && (xdp->freq == 37800)) { // level A
for (k=0; k < 14; k++, sound_datap2 += 8) {
*(datap++) = (U16)sound_datap2[0] |
(U16)(sound_datap2[4] << 8);
}
} else { // level B/C
for (k=0; k < 7; k++, sound_datap2 += 16) {
*(datap++) = (U16)(sound_datap2[ 0] >> 4) |
((U16)(sound_datap2[ 4] >> 4) << 4) |
((U16)(sound_datap2[ 8] >> 4) << 8) |
((U16)(sound_datap2[12] >> 4) << 12);
}
}
ADPCM_DecodeBlock16( &xdp->right, sound_groupsp[headtable[i]+1], data,
destp+1, 2 );
destp += 28*2;
}
}
}
else { // mono
for (j=0; j < 18; j++) {
sound_groupsp = srcp + j * 128; // sound groups header
sound_datap = sound_groupsp + 16; // sound data just after the header
for (i=0; i < nbits; i++) {
datap = data;
sound_datap2 = sound_datap + i;
if ((xdp->nbits == 8) && (xdp->freq == 37800)) { // level A
for (k=0; k < 14; k++, sound_datap2 += 8) {
*(datap++) = (U16)sound_datap2[0] |
(U16)(sound_datap2[4] << 8);
}
} else { // level B/C
for (k=0; k < 7; k++, sound_datap2 += 16) {
*(datap++) = (U16)(sound_datap2[ 0] & 0x0f) |
((U16)(sound_datap2[ 4] & 0x0f) << 4) |
((U16)(sound_datap2[ 8] & 0x0f) << 8) |
((U16)(sound_datap2[12] & 0x0f) << 12);
}
}
ADPCM_DecodeBlock16( &xdp->left, sound_groupsp[headtable[i]+0], data,
destp, 1 );
destp += 28;
datap = data;
sound_datap2 = sound_datap + i;
if ((xdp->nbits == 8) && (xdp->freq == 37800)) { // level A
for (k=0; k < 14; k++, sound_datap2 += 8) {
*(datap++) = (U16)sound_datap2[0] |
(U16)(sound_datap2[4] << 8);
}
} else { // level B/C
for (k=0; k < 7; k++, sound_datap2 += 16) {
*(datap++) = (U16)(sound_datap2[ 0] >> 4) |
((U16)(sound_datap2[ 4] >> 4) << 4) |
((U16)(sound_datap2[ 8] >> 4) << 8) |
((U16)(sound_datap2[12] >> 4) << 12);
}
}
ADPCM_DecodeBlock16( &xdp->left, sound_groupsp[headtable[i]+1], data,
destp, 1 );
destp += 28;
}
}
}
}
//============================================
//=== XA SPECIFIC ROUTINES
//============================================
typedef struct {
U8 filenum;
U8 channum;
U8 submode;
U8 coding;
U8 filenum2;
U8 channum2;
U8 submode2;
U8 coding2;
} xa_subheader_t;
#define SUB_SUB_EOF (1<<7) // end of file
#define SUB_SUB_RT (1<<6) // real-time sector
#define SUB_SUB_FORM (1<<5) // 0 form1 1 form2
#define SUB_SUB_TRIGGER (1<<4) // used for interrupt
#define SUB_SUB_DATA (1<<3) // contains data
#define SUB_SUB_AUDIO (1<<2) // contains audio
#define SUB_SUB_VIDEO (1<<1) // contains video
#define SUB_SUB_EOR (1<<0) // end of record
#define AUDIO_CODING_GET_STEREO(_X_) ( (_X_) & 3)
#define AUDIO_CODING_GET_FREQ(_X_) (((_X_) >> 2) & 3)
#define AUDIO_CODING_GET_BPS(_X_) (((_X_) >> 4) & 3)
#define AUDIO_CODING_GET_EMPHASIS(_X_) (((_X_) >> 6) & 1)
#define SUB_UNKNOWN 0
#define SUB_VIDEO 1
#define SUB_AUDIO 2
//============================================
static int parse_xa_audio_sector( xa_decode_t *xdp,
xa_subheader_t *subheadp,
unsigned char *sectorp,
int is_first_sector ) {
if ( is_first_sector ) {
switch ( AUDIO_CODING_GET_FREQ(subheadp->coding) ) {
case 0: xdp->freq = 37800; break;
case 1: xdp->freq = 18900; break;
default: xdp->freq = 0; break;
}
switch ( AUDIO_CODING_GET_BPS(subheadp->coding) ) {
case 0: xdp->nbits = 4; break;
case 1: xdp->nbits = 8; break;
default: xdp->nbits = 0; break;
}
switch ( AUDIO_CODING_GET_STEREO(subheadp->coding) ) {
case 0: xdp->stereo = 0; break;
case 1: xdp->stereo = 1; break;
default: xdp->stereo = 0; break;
}
if ( xdp->freq == 0 )
return -1;
ADPCM_InitDecode( &xdp->left );
ADPCM_InitDecode( &xdp->right );
xdp->nsamples = 18 * 28 * 8;
if (xdp->stereo == 1) xdp->nsamples /= 2;
}
xa_decode_data( xdp, sectorp );
return 0;
}
//================================================================
//=== THIS IS WHAT YOU HAVE TO CALL
//=== xdp - structure were all important data are returned
//=== sectorp - data in input
//=== pcmp - data in output
//=== is_first_sector - 1 if it's the 1st sector of the stream
//=== - 0 for any other successive sector
//=== return -1 if error
//================================================================
long xa_decode_sector( xa_decode_t *xdp,
unsigned char *sectorp, int is_first_sector ) {
if (parse_xa_audio_sector(xdp, (xa_subheader_t *)sectorp, sectorp + sizeof(xa_subheader_t), is_first_sector))
return -1;
return 0;
}
/* EXAMPLE:
"nsamples" is the number of 16 bit samples
every sample is 2 bytes in mono and 4 bytes in stereo
xa_decode_t xa;
sectorp = read_first_sector();
xa_decode_sector( &xa, sectorp, 1 );
play_wave( xa.pcm, xa.freq, xa.nsamples );
while ( --n_sectors )
{
sectorp = read_next_sector();
xa_decode_sector( &xa, sectorp, 0 );
play_wave( xa.pcm, xa.freq, xa.nsamples );
}
*/
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