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/*
* CD-ROM XA ADPCM codecs
* Copyright (c) 1999,2003 BERO
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "avcodec.h"
/**
* @file xa.c
* CD-ROM XA ADPCM codecs.
*
* Reference documents:
* http://ku-www.ss.titech.ac.jp/~yatsushi/xaadpcm.html
* vagpack & depack http://homepages.compuserve.de/bITmASTER32/psx-index.html
* readstr http://www.geocities.co.jp/Playtown/2004/
*/
typedef struct {
int s1,s2;
} PREV;
typedef struct {
PREV prev[2];
} XAContext;
#define CLIP(s) if (s<-32768) s=-32768; else if (s>32767) s=32767
static void xa_decode(short *out,const unsigned char *in,PREV *prev,int inc)
{
const static int f[5][2] = {
{0,0},
{60,0},
{115,-52},
{98,-55},
{122,-60}
};
int i,j;
for(i=0;i<4;i++) {
int shift,filter,f0,f1;
int s_1,s_2;
shift = 12 - (in[4+i*2] & 15);
filter = in[4+i*2] >> 4;
f0 = f[filter][0];
f1 = f[filter][1];
s_1 = prev->s1;
s_2 = prev->s2;
for(j=0;j<28;j++) {
int d,s,t;
d = in[16+i+j*4];
//t = d&0xf;
//if (t>=8) t-=16;
t = (signed char)(d<<4)>>4;
s = ( t<<shift ) + ((s_1*f0 + s_2*f1+32)>>6);
CLIP(s);
*out = s;
out += inc;
s_2 = s_1;
s_1 = s;
}
if (inc==2) { /* stereo */
prev->s1 = s_1;
prev->s2 = s_2;
s_1 = prev[1].s1;
s_2 = prev[1].s2;
out = out + 1 - 28*2;
}
shift = 12 - (in[5+i*2] & 15);
filter = in[5+i*2] >> 4;
f0 = f[filter][0];
f1 = f[filter][1];
for(j=0;j<28;j++) {
int d,s,t;
d = in[16+i+j*4];
//t = d>>4;
//if (t>=8) t-=16;
t = (signed char)d >> 4;
s = ( t<<shift ) + ((s_1*f0 + s_2*f1+32)>>6);
CLIP(s);
*out = s;
out += inc;
s_2 = s_1;
s_1 = s;
}
if (inc==2) { /* stereo */
prev[1].s1 = s_1;
prev[1].s2 = s_2;
out -= 1;
} else {
prev[0].s1 = s_1;
prev[0].s2 = s_2;
}
}
}
static int xa_decode_init(AVCodecContext * avctx)
{
XAContext *c = avctx->priv_data;
printf("xa init %d\n",avctx->channels);
c->prev[0].s1 = 0;
c->prev[0].s2 = 0;
c->prev[1].s1 = 0;
c->prev[1].s2 = 0;
switch(avctx->channels) {
case 1:
case 2:
return 0;
default:
return -1;
}
}
static int xa_decode_frame(AVCodecContext *avctx,
void *data, int *data_size,
const uint8_t *buf0, int buf_size)
{
XAContext *c = avctx->priv_data;
short *samples = data;
const uint8_t *buf = buf0;
// printf("xa decode %d\n",buf_size);
c->prev[0].s1 = 0;
c->prev[0].s2 = 0;
c->prev[1].s1 = 0;
c->prev[1].s2 = 0;
while(buf_size>=128) {
xa_decode(samples,buf,c->prev,avctx->channels);
buf+=128;
samples += 28*8;
buf_size-=128;
}
*data_size = (char*)samples - (char*)data;
return buf-buf0;
}
#define DEFINE_ENCODER(id, name,context) \
AVCodec name ## _encoder = { \
#name, \
CODEC_TYPE_AUDIO, \
id, \
sizeof(context), \
name ## _encode_init, \
name ## _encode_frame, \
name ## _encode_close, \
NULL, \
};
#define DEFINE_DECODER(id, name,context) \
AVCodec name ## _decoder = { \
#name, \
CODEC_TYPE_AUDIO, \
id, \
sizeof(context), \
name ## _decode_init, \
NULL, \
NULL, \
name ## _decode_frame, \
};
DEFINE_DECODER(CODEC_ID_ADPCM_XA,xa,XAContext)
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