lib/envelope.c

   1 /********************************************************************
   2  *                                                                  *
   3  * THIS FILE IS PART OF THE Ogg Vorbis SOFTWARE CODEC SOURCE CODE.  *
   4  * USE, DISTRIBUTION AND REPRODUCTION OF THIS SOURCE IS GOVERNED BY *
   5  * THE GNU PUBLIC LICENSE 2, WHICH IS INCLUDED WITH THIS SOURCE.    *
   6  * PLEASE READ THESE TERMS DISTRIBUTING.                            *
   7  *                                                                  *
   8  * THE OggSQUISH SOURCE CODE IS (C) COPYRIGHT 1994-2000             *
   9  * by Monty <monty@xiph.org> and The XIPHOPHORUS Company            *
  10  * http://www.xiph.org/                                             *
  11  *                                                                  *
  12  ********************************************************************
  13
  14  function: PCM data envelope analysis and manipulation
  15  last mod: $Id: envelope.c,v 1.12 1999/12/30 07:26:36 xiphmont Exp $
  16
  17  Preecho calculation.
  18
  19  ********************************************************************/
  20
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <stdio.h>
  24 #include <math.h>
  25
  26 #include "os.h"
  27 #include "codec.h"
  28 #include "mdct.h"
  29 #include "envelope.h"
  30 #include "bitwise.h"
  31 #include "window.h"
  32
  33 void _ve_envelope_init(envelope_lookup *e,int samples_per){
  34   int i;
  35
  36   e->winlen=samples_per;
  37   e->window=malloc(e->winlen*sizeof(double));
  38   mdct_init(&e->mdct,e->winlen);
  39
  40   /* We just use a straight sin(x) window for this */
  41   for(i=0;i<e->winlen;i++)
  42     e->window[i]=sin((i+.5)/e->winlen*M_PI);
  43
  44 }
  45
  46 void _ve_envelope_clear(envelope_lookup *e){
  47   if(e->window)free(e->window);
  48   mdct_clear(&e->mdct);
  49   memset(e,0,sizeof(envelope_lookup));
  50 }
  51
  52 /* use MDCT for spectral power estimation */
  53
  54 static void _ve_deltas(double *deltas,double *pcm,int n,double *window,
  55                        int winsize,mdct_lookup *m){
  56   int i,j;
  57   double *out=alloca(sizeof(double)*winsize/2);
  58
  59   for(j=0;j<n;j++){
  60     double acc=0.;
  61
  62     mdct_forward(m,pcm+j*winsize,out,window);
  63     for(i=winsize/10;i<winsize/2;i++)
  64       acc+=fabs(out[i]);
  65     if(deltas[j]<acc)deltas[j]=acc;
  66   }
  67 }
  68
  69 void _ve_envelope_deltas(vorbis_dsp_state *v){
  70   vorbis_info *vi=v->vi;
  71   int step=vi->envelopesa;
  72
  73   int dtotal=v->pcm_current/vi->envelopesa;
  74   int dcurr=v->envelope_current;
  75   int pch;
  76
  77   if(dtotal>dcurr){
  78     double *mult=v->multipliers+dcurr;
  79     memset(mult,0,sizeof(double)*(dtotal-dcurr));
  80
  81     for(pch=0;pch<vi->channels;pch++){
  82       double *pcm=v->pcm[pch]+dcurr*step;
  83       _ve_deltas(mult,pcm,dtotal-dcurr,v->ve.window,v->ve.winlen,&v->ve.mdct);
  84     }
  85     v->envelope_current=dtotal;
  86
  87 #ifdef ANALYSIS
  88     {
  89       static int frameno=0;
  90       FILE *out;
  91       char buffer[80];
  92       int j,k;
  93
  94       sprintf(buffer,"delt%d.m",frameno);
  95       out=fopen(buffer,"w+");
  96       for(j=0;j<v->envelope_current;j++)
  97         fprintf(out,"%d %g\n",j*vi->envelopesa+vi->envelopesa/2,v->multipliers[j]);
  98       fclose(out);
  99
 100       sprintf(buffer,"deltpcm%d.m",frameno++);
 101       out=fopen(buffer,"w+");
 102       for(k=0;k<vi->channels;k++){
 103         for(j=0;j<v->pcm_current;j++)
 104           fprintf(out,"%d %g\n",j,v->pcm[k][j]);
 105         fprintf(out,"\n");
 106       }
 107       fclose(out);
 108     }
 109 #endif
 110
 111   }
 112 }
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