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 1994-1999             *
   9  * by 1999 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  author: Monty <xiphmont@mit.edu>
  16  modifications by: Monty
  17  last modification date: Oct 22 1999
  18
  19  Preecho calculation.
  20
  21  ********************************************************************/
  22
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <stdio.h>
  26 #include <math.h>
  27
  28 #include "codec.h"
  29 #include "mdct.h"
  30 #include "envelope.h"
  31 #include "bitwise.h"
  32 #include "window.h"
  33
  34 void _ve_envelope_init(envelope_lookup *e,int samples_per){
  35   int i;
  36
  37   e->winlen=samples_per;
  38   e->window=malloc(e->winlen*sizeof(double));
  39   mdct_init(&e->mdct,e->winlen);
  40
  41   /* We just use a straight sin(x) window for this */
  42   for(i=0;i<e->winlen;i++)
  43     e->window[i]=sin((i+.5)/e->winlen*M_PI);
  44
  45 }
  46
  47 void _ve_envelope_clear(envelope_lookup *e){
  48   if(e->window)free(e->window);
  49   mdct_clear(&e->mdct);
  50   memset(e,0,sizeof(envelope_lookup));
  51 }
  52
  53 /* use MDCT for spectral power estimation */
  54
  55 static void _ve_deltas(double *deltas,double *pcm,int n,double *window,
  56                        int winsize,mdct_lookup *m){
  57   int i,j;
  58   double out[winsize/2];
  59
  60   for(j=0;j<n;j++){
  61     double acc=0.;
  62
  63     mdct_forward(m,pcm+j*winsize,out,window);
  64     for(i=winsize/10;i<winsize/2;i++)
  65       acc+=fabs(out[i]);
  66     if(deltas[j]<acc)deltas[j]=acc;
  67   }
  68 }
  69
  70 void _ve_envelope_deltas(vorbis_dsp_state *v){
  71   vorbis_info *vi=v->vi;
  72   int step=vi->envelopesa;
  73
  74   int dtotal=v->pcm_current/vi->envelopesa;
  75   int dcurr=v->envelope_current;
  76   int pch;
  77
  78   if(dtotal>dcurr){
  79     double *mult=v->multipliers+dcurr;
  80     memset(mult,0,sizeof(double)*(dtotal-dcurr));
  81
  82     for(pch=0;pch<vi->channels;pch++){
  83       double *pcm=v->pcm[pch]+dcurr*step;
  84       _ve_deltas(mult,pcm,dtotal-dcurr,v->ve.window,v->ve.winlen,&v->ve.mdct);
  85     }
  86     v->envelope_current=dtotal;
  87
  88 #ifdef ANALYSIS
  89     {
  90       static int frameno=0;
  91       FILE *out;
  92       char buffer[80];
  93       int j,k;
  94
  95       sprintf(buffer,"delt%d.m",frameno);
  96       out=fopen(buffer,"w+");
  97       for(j=0;j<v->envelope_current;j++)
  98         fprintf(out,"%d %g\n",j*vi->envelopesa+vi->envelopesa/2,v->multipliers[j]);
  99       fclose(out);
 100
 101       sprintf(buffer,"deltpcm%d.m",frameno++);
 102       out=fopen(buffer,"w+");
 103       for(k=0;k<vi->channels;k++){
 104         for(j=0;j<v->pcm_current;j++)
 105           fprintf(out,"%d %g\n",j,v->pcm[k][j]);
 106         fprintf(out,"\n");
 107       }
 108       fclose(out);
 109     }
 110 #endif
 111
 112   }
 113 }
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