decode_i386.cpp
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上传日期:2007-01-08
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文件大小:5k
- /**************************************************************************************
- * *
- * This application contains code from OpenDivX and is released as a "Larger Work" *
- * under that license. Consistant with that license, this application is released *
- * under the GNU General Public License. *
- * *
- * The OpenDivX license can be found at: http://www.projectmayo.com/opendivx/docs.php *
- * The GPL can be found at: http://www.gnu.org/copyleft/gpl.html *
- * *
- * Authors: Damien Chavarria <roy204 at projectmayo.com> *
- * *
- **************************************************************************************/
- /*
- * Mpeg Layer-1,2,3 audio decoder
- * ------------------------------
- * copyright (c) 1995,1996,1997 by Michael Hipp, All rights reserved.
- *
- * slighlty optimized for machines without autoincrement/decrement.
- * The performance is highly compiler dependend. Maybe
- * the decode.c version for 'normal' processor may be faster
- * even for Intel processors.
- */
- #include <stdlib.h>
- #include <math.h>
- #include <string.h>
- #include "mpg123.h"
- #include "mpglib.h"
- extern struct mpstr *gmp;
- /* old WRITE_SAMPLE */
- #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_1to1_mono(real *bandPtr,unsigned char *samples,int *pnt)
- {
- short samples_tmp[64];
- short *tmp1 = samples_tmp;
- int i,ret;
- int pnt1 = 0;
- ret = synth_1to1(bandPtr,0,(unsigned char *) samples_tmp,&pnt1);
- samples += *pnt;
- for(i=0;i<32;i++) {
- *( (short *) samples) = *tmp1;
- samples += 2;
- tmp1 += 2;
- }
- *pnt += 64;
- return ret;
- }
- int synth_1to1(real *bandPtr,int channel,unsigned char *out,int *pnt)
- {
- static const int step = 2;
- int bo;
- short *samples = (short *) (out + *pnt);
- real *b0,(*buf)[0x110];
- int clip = 0;
- int bo1;
- bo = gmp->synth_bo;
- if(!channel) {
- bo--;
- bo &= 0xf;
- buf = gmp->synth_buffs[0];
- }
- else {
- samples++;
- buf = gmp->synth_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);
- }
- gmp->synth_bo = bo;
-
- {
- register int j;
- real *window = decwin + 16 - bo1;
- for (j=16;j;j--,b0+=0x10,window+=0x20,samples+=step)
- {
- real sum;
- sum = window[0x0] * b0[0x0];
- sum -= window[0x1] * b0[0x1];
- sum += window[0x2] * b0[0x2];
- sum -= window[0x3] * b0[0x3];
- sum += window[0x4] * b0[0x4];
- sum -= window[0x5] * b0[0x5];
- sum += window[0x6] * b0[0x6];
- sum -= window[0x7] * b0[0x7];
- sum += window[0x8] * b0[0x8];
- sum -= window[0x9] * b0[0x9];
- sum += window[0xA] * b0[0xA];
- sum -= window[0xB] * b0[0xB];
- sum += window[0xC] * b0[0xC];
- sum -= window[0xD] * b0[0xD];
- sum += window[0xE] * b0[0xE];
- sum -= window[0xF] * b0[0xF];
- WRITE_SAMPLE(samples,sum,clip);
- }
- {
- 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);
- b0-=0x10,window-=0x20,samples+=step;
- }
- window += bo1<<1;
- for (j=15;j;j--,b0-=0x10,window-=0x20,samples+=step)
- {
- real sum;
- sum = -window[-0x1] * b0[0x0];
- sum -= window[-0x2] * b0[0x1];
- sum -= window[-0x3] * b0[0x2];
- sum -= window[-0x4] * b0[0x3];
- sum -= window[-0x5] * b0[0x4];
- sum -= window[-0x6] * b0[0x5];
- sum -= window[-0x7] * b0[0x6];
- sum -= window[-0x8] * b0[0x7];
- sum -= window[-0x9] * b0[0x8];
- sum -= window[-0xA] * b0[0x9];
- sum -= window[-0xB] * b0[0xA];
- sum -= window[-0xC] * b0[0xB];
- sum -= window[-0xD] * b0[0xC];
- sum -= window[-0xE] * b0[0xD];
- sum -= window[-0xF] * b0[0xE];
- sum -= window[-0x0] * b0[0xF];
- WRITE_SAMPLE(samples,sum,clip);
- }
- }
- *pnt += 128;
- return clip;
- }