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tdemultimedia/mpg123_artsplugin/mpg123/decode_4to1.c

241 lines
5.3 KiB

/*
* Mpeg Layer-1,2,3 audio decoder
* ------------------------------
* copyright (c) 1995,1996,1997 by Michael Hipp, All rights reserved.
* See also 'README'
* version for slower machines .. decodes only every fourth sample
* dunno why it sounds THIS annoying (maybe we should adapt the window?)
* absolutely not optimized for this operation
*/
#include <stdlib.h>
#include <math.h>
#include <string.h>
#include "mpg123.h"
#define WRITE_SAMPLE(samples,sum,clip) \
if( (sum) > 32767.0) { *(samples) = 0x7fff; (clip)++; } \
else if( (sum) < -32768.0) { *(samples) = -0x8000; (clip)++; } \
else { *(samples) = sum; }
int synth_4to1_8bit(real *bandPtr,int channel,unsigned char *samples,int *pnt)
{
short samples_tmp[16];
short *tmp1 = samples_tmp + channel;
int i,ret;
int pnt1 = 0;
ret = synth_4to1(bandPtr,channel,(unsigned char *) samples_tmp,&pnt1);
samples += channel + *pnt;
for(i=0;i<8;i++) {
*samples = conv16to8[*tmp1>>AUSHIFT];
samples += 2;
tmp1 += 2;
}
*pnt += 16;
return ret;
}
int synth_4to1_8bit_mono(real *bandPtr,unsigned char *samples,int *pnt)
{
short samples_tmp[16];
short *tmp1 = samples_tmp;
int i,ret;
int pnt1 = 0;
ret = synth_4to1(bandPtr,0,(unsigned char *) samples_tmp,&pnt1);
samples += *pnt;
for(i=0;i<8;i++) {
*samples++ = conv16to8[*tmp1>>AUSHIFT];
tmp1 += 2;
}
*pnt += 8;
return ret;
}
int synth_4to1_8bit_mono2stereo(real *bandPtr,unsigned char *samples,int *pnt)
{
short samples_tmp[16];
short *tmp1 = samples_tmp;
int i,ret;
int pnt1 = 0;
ret = synth_4to1(bandPtr,0,(unsigned char *) samples_tmp,&pnt1);
samples += *pnt;
for(i=0;i<8;i++) {
*samples++ = conv16to8[*tmp1>>AUSHIFT];
*samples++ = conv16to8[*tmp1>>AUSHIFT];
tmp1 += 2;
}
*pnt += 16;
return ret;
}
int synth_4to1_mono(real *bandPtr,unsigned char *samples,int *pnt)
{
short samples_tmp[16];
short *tmp1 = samples_tmp;
int i,ret;
int pnt1 = 0;
ret = synth_4to1(bandPtr,0,(unsigned char *) samples_tmp,&pnt1);
samples += *pnt;
for(i=0;i<8;i++) {
*( (short *)samples) = *tmp1;
samples += 2;
tmp1 += 2;
}
*pnt += 16;
return ret;
}
int synth_4to1_mono2stereo(real *bandPtr,unsigned char *samples,int *pnt)
{
int i,ret;
ret = synth_4to1(bandPtr,0,samples,pnt);
samples = samples + *pnt - 32;
for(i=0;i<8;i++) {
((short *)samples)[1] = ((short *)samples)[0];
samples+=4;
}
return ret;
}
int synth_4to1(real *bandPtr,int channel,unsigned char *out,int *pnt)
{
static real buffs[2][2][0x110];
static const int step = 2;
static int bo = 1;
short *samples = (short *) (out + *pnt);
real *b0,(*buf)[0x110];
int clip = 0;
int bo1;
#ifndef NO_EQUALIZER
if(param.enable_equalizer)
do_equalizer(bandPtr,channel);
#endif
if(!channel) {
bo--;
bo &= 0xf;
buf = buffs[0];
}
else {
samples++;
buf = buffs[1];
}
if(bo & 0x1) {
b0 = buf[0];
bo1 = bo;
dct64(buf[1]+((bo+1)&0xf),buf[0]+bo,bandPtr);
}
else {
b0 = buf[1];
bo1 = bo+1;
dct64(buf[0]+bo,buf[1]+bo+1,bandPtr);
}
{
int j;
real *window = decwin + 16 - bo1;
for (j=4;j;j--,b0+=0x30,window+=0x70)
{
real sum;
sum = *window++ * *b0++;
sum -= *window++ * *b0++;
sum += *window++ * *b0++;
sum -= *window++ * *b0++;
sum += *window++ * *b0++;
sum -= *window++ * *b0++;
sum += *window++ * *b0++;
sum -= *window++ * *b0++;
sum += *window++ * *b0++;
sum -= *window++ * *b0++;
sum += *window++ * *b0++;
sum -= *window++ * *b0++;
sum += *window++ * *b0++;
sum -= *window++ * *b0++;
sum += *window++ * *b0++;
sum -= *window++ * *b0++;
WRITE_SAMPLE(samples,sum,clip); samples += step;
#if 0
WRITE_SAMPLE(samples,sum,clip); samples += step;
WRITE_SAMPLE(samples,sum,clip); samples += step;
WRITE_SAMPLE(samples,sum,clip); samples += step;
#endif
}
{
real sum;
sum = window[0x0] * b0[0x0];
sum += window[0x2] * b0[0x2];
sum += window[0x4] * b0[0x4];
sum += window[0x6] * b0[0x6];
sum += window[0x8] * b0[0x8];
sum += window[0xA] * b0[0xA];
sum += window[0xC] * b0[0xC];
sum += window[0xE] * b0[0xE];
WRITE_SAMPLE(samples,sum,clip); samples += step;
#if 0
WRITE_SAMPLE(samples,sum,clip); samples += step;
WRITE_SAMPLE(samples,sum,clip); samples += step;
WRITE_SAMPLE(samples,sum,clip); samples += step;
#endif
b0-=0x40,window-=0x80;
}
window += bo1<<1;
for (j=3;j;j--,b0-=0x50,window-=0x70)
{
real sum;
sum = -*(--window) * *b0++;
sum -= *(--window) * *b0++;
sum -= *(--window) * *b0++;
sum -= *(--window) * *b0++;
sum -= *(--window) * *b0++;
sum -= *(--window) * *b0++;
sum -= *(--window) * *b0++;
sum -= *(--window) * *b0++;
sum -= *(--window) * *b0++;
sum -= *(--window) * *b0++;
sum -= *(--window) * *b0++;
sum -= *(--window) * *b0++;
sum -= *(--window) * *b0++;
sum -= *(--window) * *b0++;
sum -= *(--window) * *b0++;
sum -= *(--window) * *b0++;
WRITE_SAMPLE(samples,sum,clip); samples += step;
#if 0
WRITE_SAMPLE(samples,sum,clip); samples += step;
WRITE_SAMPLE(samples,sum,clip); samples += step;
WRITE_SAMPLE(samples,sum,clip); samples += step;
#endif
}
}
*pnt += 32;
return clip;
}