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291 lines
6.0 KiB
291 lines
6.0 KiB
/*
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* Mpeg Layer-1,2,3 audio decoder
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* ------------------------------
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* copyright (c) 1995,1996,1997 by Michael Hipp, All rights reserved.
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* See also 'README'
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*
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* N->M down/up sampling. Not optimized for speed.
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*/
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#include <stdlib.h>
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#include <math.h>
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#include <string.h>
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#include "mpg123.h"
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#define WRITE_SAMPLE(samples,sum,clip) \
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if( (sum) > 32767.0) { *(samples) = 0x7fff; (clip)++; } \
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else if( (sum) < -32768.0) { *(samples) = -0x8000; (clip)++; } \
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else { *(samples) = sum; }
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#define NTOM_MUL (32768)
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static unsigned long ntom_val[2] = { NTOM_MUL>>1,NTOM_MUL>>1 };
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static unsigned long ntom_step = NTOM_MUL;
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void synth_ntom_set_step(long m,long n)
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{
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if(param.verbose > 1)
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fprintf(stderr,"Init rate converter: %ld->%ld\n",m,n);
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if(n >= 96000 || m >= 96000 || m == 0 || n == 0) {
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fprintf(stderr,"NtoM converter: illegal rates\n");
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exit(1);
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}
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n *= NTOM_MUL;
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ntom_step = n / m;
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if(ntom_step > 8*NTOM_MUL) {
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fprintf(stderr,"max. 1:8 conversion allowed!\n");
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exit(1);
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}
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ntom_val[0] = ntom_val[1] = NTOM_MUL>>1;
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}
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int synth_ntom_8bit(real *bandPtr,int channel,unsigned char *samples,int *pnt)
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{
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short samples_tmp[8*64];
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short *tmp1 = samples_tmp + channel;
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int i,ret;
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int pnt1 = 0;
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ret = synth_ntom(bandPtr,channel,(unsigned char *) samples_tmp,&pnt1);
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samples += channel + *pnt;
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for(i=0;i<(pnt1>>2);i++) {
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*samples = conv16to8[*tmp1>>AUSHIFT];
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samples += 2;
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tmp1 += 2;
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}
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*pnt += pnt1>>1;
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return ret;
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}
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int synth_ntom_8bit_mono(real *bandPtr,unsigned char *samples,int *pnt)
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{
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short samples_tmp[8*64];
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short *tmp1 = samples_tmp;
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int i,ret;
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int pnt1 = 0;
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ret = synth_ntom(bandPtr,0,(unsigned char *) samples_tmp,&pnt1);
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samples += *pnt;
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for(i=0;i<(pnt1>>2);i++) {
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*samples++ = conv16to8[*tmp1>>AUSHIFT];
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tmp1 += 2;
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}
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*pnt += pnt1 >> 2;
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return ret;
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}
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int synth_ntom_8bit_mono2stereo(real *bandPtr,unsigned char *samples,int *pnt)
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{
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short samples_tmp[8*64];
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short *tmp1 = samples_tmp;
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int i,ret;
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int pnt1 = 0;
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ret = synth_ntom(bandPtr,0,(unsigned char *) samples_tmp,&pnt1);
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samples += *pnt;
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for(i=0;i<(pnt1>>2);i++) {
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*samples++ = conv16to8[*tmp1>>AUSHIFT];
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*samples++ = conv16to8[*tmp1>>AUSHIFT];
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tmp1 += 2;
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}
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*pnt += pnt1 >> 1;
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return ret;
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}
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int synth_ntom_mono(real *bandPtr,unsigned char *samples,int *pnt)
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{
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short samples_tmp[8*64];
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short *tmp1 = samples_tmp;
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int i,ret;
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int pnt1 = 0;
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ret = synth_ntom(bandPtr,0,(unsigned char *) samples_tmp,&pnt1);
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samples += *pnt;
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for(i=0;i<(pnt1>>2);i++) {
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*( (short *)samples) = *tmp1;
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samples += 2;
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tmp1 += 2;
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}
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*pnt += pnt1 >> 1;
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return ret;
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}
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int synth_ntom_mono2stereo(real *bandPtr,unsigned char *samples,int *pnt)
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{
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int i,ret;
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int pnt1 = *pnt;
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ret = synth_ntom(bandPtr,0,samples,pnt);
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samples += pnt1;
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for(i=0;i<((*pnt-pnt1)>>2);i++) {
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((short *)samples)[1] = ((short *)samples)[0];
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samples+=4;
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}
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return ret;
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}
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int synth_ntom(real *bandPtr,int channel,unsigned char *out,int *pnt)
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{
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static real buffs[2][2][0x110];
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static const int step = 2;
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static int bo = 1;
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short *samples = (short *) (out + *pnt);
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real *b0,(*buf)[0x110];
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int clip = 0;
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int bo1;
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int ntom;
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#ifndef NO_EQUALIZER
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if(param.enable_equalizer)
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do_equalizer(bandPtr,channel);
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#endif
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if(!channel) {
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bo--;
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bo &= 0xf;
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buf = buffs[0];
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ntom = ntom_val[1] = ntom_val[0];
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}
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else {
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samples++;
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out += 2; /* to compute the right *pnt value */
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buf = buffs[1];
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ntom = ntom_val[1];
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}
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if(bo & 0x1) {
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b0 = buf[0];
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bo1 = bo;
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dct64(buf[1]+((bo+1)&0xf),buf[0]+bo,bandPtr);
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}
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else {
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b0 = buf[1];
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bo1 = bo+1;
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dct64(buf[0]+bo,buf[1]+bo+1,bandPtr);
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}
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{
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register int j;
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real *window = decwin + 16 - bo1;
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for (j=16;j;j--,window+=0x10)
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{
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real sum;
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ntom += ntom_step;
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if(ntom < NTOM_MUL) {
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window += 16;
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b0 += 16;
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continue;
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}
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sum = *window++ * *b0++;
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sum -= *window++ * *b0++;
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sum += *window++ * *b0++;
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sum -= *window++ * *b0++;
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sum += *window++ * *b0++;
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sum -= *window++ * *b0++;
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sum += *window++ * *b0++;
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sum -= *window++ * *b0++;
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sum += *window++ * *b0++;
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sum -= *window++ * *b0++;
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sum += *window++ * *b0++;
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sum -= *window++ * *b0++;
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sum += *window++ * *b0++;
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sum -= *window++ * *b0++;
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sum += *window++ * *b0++;
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sum -= *window++ * *b0++;
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while(ntom >= NTOM_MUL) {
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WRITE_SAMPLE(samples,sum,clip);
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samples += step;
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ntom -= NTOM_MUL;
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}
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}
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ntom += ntom_step;
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if(ntom >= NTOM_MUL)
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{
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real sum;
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sum = window[0x0] * b0[0x0];
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sum += window[0x2] * b0[0x2];
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sum += window[0x4] * b0[0x4];
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sum += window[0x6] * b0[0x6];
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sum += window[0x8] * b0[0x8];
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sum += window[0xA] * b0[0xA];
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sum += window[0xC] * b0[0xC];
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sum += window[0xE] * b0[0xE];
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while(ntom >= NTOM_MUL) {
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WRITE_SAMPLE(samples,sum,clip);
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samples += step;
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ntom -= NTOM_MUL;
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}
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}
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b0-=0x10,window-=0x20;
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window += bo1<<1;
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for (j=15;j;j--,b0-=0x20,window-=0x10)
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{
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real sum;
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ntom += ntom_step;
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if(ntom < NTOM_MUL) {
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window -= 16;
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b0 += 16;
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continue;
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}
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sum = -*(--window) * *b0++;
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sum -= *(--window) * *b0++;
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sum -= *(--window) * *b0++;
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sum -= *(--window) * *b0++;
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sum -= *(--window) * *b0++;
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sum -= *(--window) * *b0++;
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sum -= *(--window) * *b0++;
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sum -= *(--window) * *b0++;
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sum -= *(--window) * *b0++;
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sum -= *(--window) * *b0++;
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sum -= *(--window) * *b0++;
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sum -= *(--window) * *b0++;
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sum -= *(--window) * *b0++;
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sum -= *(--window) * *b0++;
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sum -= *(--window) * *b0++;
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sum -= *(--window) * *b0++;
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while(ntom >= NTOM_MUL) {
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WRITE_SAMPLE(samples,sum,clip);
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samples += step;
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ntom -= NTOM_MUL;
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}
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}
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}
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ntom_val[channel] = ntom;
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*pnt = ((unsigned char *) samples - out);
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return clip;
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}
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