lib/envelope.c

   1 /********************************************************************
   2  *                                                                  *
   3  * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE.   *
   4  * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *
   5  * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
   6  * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *
   7  *                                                                  *
   8  * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2001             *
   9  * by the XIPHOPHORUS Company http://www.xiph.org/                  *
  10
  11  ********************************************************************
  12
  13  function: PCM data envelope analysis and manipulation
  14  last mod: $Id: envelope.c,v 1.37 2001/08/13 01:36:56 xiphmont Exp $
  15
  16  Preecho calculation.
  17
  18  ********************************************************************/
  19
  20 #include <stdlib.h>
  21 #include <string.h>
  22 #include <stdio.h>
  23 #include <math.h>
  24 #include <ogg/ogg.h>
  25 #include "vorbis/codec.h"
  26 #include "codec_internal.h"
  27
  28 #include "os.h"
  29 #include "scales.h"
  30 #include "envelope.h"
  31 #include "misc.h"
  32 #include "iir.c" /* Yes, ugly, but needed for inlining */
  33
  34 /* Digital filter designed by mkfilter/mkshape/gencode A.J. Fisher */
  35
  36 static int   cheb_highpass_stages=6;
  37 static float cheb_highpass_B[]={1.f,-6.f,15.f,-20.f,15.f,-6.f,1.f};
  38
  39 static int   cheb_bandpass_stages=6;
  40 static float cheb_bandpass_B[]={-1.f,0.f,3.f,0.f,-3.f,0.f,1.f};
  41
  42
  43 /* 10kHz Chebyshev highpass */
  44 static float cheb_highpass10k_gain= 54.34519586f;
  45 static float cheb_highpass10k_A[]={
  46   -0.2064797169f,
  47   -0.5609713214f,
  48   -1.1352465327f,
  49   -1.4495555418f,
  50   -1.7938140760f,
  51   -0.9473564683f};
  52
  53 /* 6kHz-10kHz Chebyshev bandpass */
  54 static float cheb_bandpass6k_gain=113.4643935f;
  55 static float cheb_bandpass6k_A[]={
  56   -0.5712621337f,
  57   1.5626130710f,
  58   -3.3348854983f,
  59   4.0471340821f,
  60   -4.0051680331f,
  61   2.2786325610f};
  62
  63 /* 3kHz-6kHz Chebyshev bandpass */
  64 static float cheb_bandpass3k_gain= 248.8359377f;
  65 static float cheb_bandpass3k_A[]={
  66   -0.6564230022f,
  67   3.3747911257f,
  68   -8.0098635981f,
  69   11.0040876874f,
  70   -9.2250963484f,
  71   4.4760355389f};
  72
  73 /* 1.5kHz-3kHz Chebyshev bandpass */
  74 static float cheb_bandpass1k_gain= 1798.537183f;
  75 static float cheb_bandpass1k_A[]={
  76   -0.8097527363f,
  77   4.7725742682f,
  78   -11.9800219408f,
  79   16.3770336223f,
  80   -12.8553129536f,
  81   5.4948074309f};
  82
  83 void _ve_envelope_init(envelope_lookup *e,vorbis_info *vi){
  84   codec_setup_info *ci=vi->codec_setup;
  85   vorbis_info_psy_global *gi=ci->psy_g_param;
  86   int ch=vi->channels;
  87   int window=gi->envelopesa;
  88   int i;
  89   e->winlength=window;
  90   e->minenergy=fromdB(gi->preecho_minenergy);
  91   e->iir=_ogg_calloc(ch*4,sizeof(IIR_state));
  92   e->filtered=_ogg_calloc(ch*4,sizeof(float *));
  93   e->ch=ch;
  94   e->storage=128;
  95   for(i=0;i<ch*4;i+=4){
  96
  97     IIR_init(e->iir+i,cheb_highpass_stages,cheb_highpass10k_gain,
  98              cheb_highpass10k_A,cheb_highpass_B);
  99     IIR_init(e->iir+i+1,cheb_bandpass_stages,cheb_bandpass6k_gain,
 100              cheb_bandpass6k_A,cheb_bandpass_B);
 101     IIR_init(e->iir+i+2,cheb_bandpass_stages,cheb_bandpass3k_gain,
 102              cheb_bandpass3k_A,cheb_bandpass_B);
 103     IIR_init(e->iir+i+3,cheb_bandpass_stages,cheb_bandpass1k_gain,
 104              cheb_bandpass1k_A,cheb_bandpass_B);
 105
 106     e->filtered[i]=_ogg_calloc(e->storage,sizeof(float));
 107     e->filtered[i+1]=_ogg_calloc(e->storage,sizeof(float));
 108     e->filtered[i+2]=_ogg_calloc(e->storage,sizeof(float));
 109     e->filtered[i+3]=_ogg_calloc(e->storage,sizeof(float));
 110   }
 111
 112 }
 113
 114 void _ve_envelope_clear(envelope_lookup *e){
 115   int i;
 116   for(i=0;i<e->ch*4;i++){
 117     IIR_clear((e->iir+i));
 118     _ogg_free(e->filtered[i]);
 119   }
 120   _ogg_free(e->filtered);
 121   _ogg_free(e->iir);
 122   memset(e,0,sizeof(envelope_lookup));
 123 }
 124
 125 /* straight threshhold based until we find something that works better
 126    and isn't patented */
 127 static float _ve_deltai(envelope_lookup *ve,float *pre,float *post){
 128   long n=ve->winlength;
 129
 130   long i;
 131
 132   /* we want to have a 'minimum bar' for energy, else we're just
 133      basing blocks on quantization noise that outweighs the signal
 134      itself (for low power signals) */
 135
 136   float minV=ve->minenergy;
 137   float A=minV*minV*n;
 138   float B=A;
 139
 140   for(i=0;i<n;i++){
 141     A+=pre[i]*pre[i];
 142     B+=post[i]*post[i];
 143   }
 144
 145   A=todB(&A);
 146   B=todB(&B);
 147
 148   return(B-A);
 149 }
 150
 151 long _ve_envelope_search(vorbis_dsp_state *v,long searchpoint){
 152   vorbis_info *vi=v->vi;
 153   codec_setup_info *ci=vi->codec_setup;
 154   vorbis_info_psy_global *gi=ci->psy_g_param;
 155   envelope_lookup *ve=((backend_lookup_state *)(v->backend_state))->ve;
 156   long i,j,k;
 157
 158   /* make sure we have enough storage to match the PCM */
 159   if(v->pcm_storage>ve->storage){
 160     ve->storage=v->pcm_storage;
 161     for(i=0;i<ve->ch*4;i++)
 162       ve->filtered[i]=_ogg_realloc(ve->filtered[i],ve->storage*sizeof(float));
 163   }
 164
 165   /* catch up the highpass to match the pcm */
 166   for(i=0;i<ve->ch;i++){
 167     float *pcm=v->pcm[i];
 168     float *filtered0=ve->filtered[i*4];
 169     float *filtered1=ve->filtered[i*4+1];
 170     float *filtered2=ve->filtered[i*4+2];
 171     float *filtered3=ve->filtered[i*4+3];
 172     IIR_state *iir0=ve->iir+i*4;
 173     IIR_state *iir1=ve->iir+i*4+1;
 174     IIR_state *iir2=ve->iir+i*4+2;
 175     IIR_state *iir3=ve->iir+i*4+3;
 176     int flag=1;
 177     for(j=ve->current;j<v->pcm_current;j++){
 178       filtered0[j]=IIR_filter(iir0,pcm[j]);
 179       filtered1[j]=IIR_filter_Band(iir1,pcm[j]);
 180       filtered2[j]=IIR_filter_Band(iir2,pcm[j]);
 181       filtered3[j]=IIR_filter_Band(iir3,pcm[j]);
 182       if(pcm[j])flag=0;
 183     }
 184     if(flag && ve->current+64<v->pcm_current){
 185       IIR_reset(iir0);
 186       IIR_reset(iir1);
 187       IIR_reset(iir2);
 188       IIR_reset(iir3);
 189     }
 190
 191   }
 192
 193   ve->current=v->pcm_current;
 194
 195   /* Now search through our cached highpass data for breaking points */
 196   /* starting point */
 197   if(v->W)
 198     j=v->centerW+ci->blocksizes[1]/4-ci->blocksizes[0]/4;
 199   else
 200     j=v->centerW;
 201
 202   if(j<ve->lastmark)j=ve->lastmark;
 203
 204   while(j+ve->winlength<=v->pcm_current){
 205     if(j>=searchpoint)return(1);
 206
 207     ve->lastmark=j;
 208     for(i=0;i<ve->ch;i++){
 209       for(k=0;k<4;k++){
 210         float *filtered=ve->filtered[i*4+k]+j;
 211         float m=_ve_deltai(ve,filtered-ve->winlength,filtered);
 212
 213         if(m>gi->preecho_thresh[k])return(0);
 214         if(m<gi->postecho_thresh[k])return(0);
 215
 216       }
 217     }
 218
 219     j+=min(ci->blocksizes[0],ve->winlength)/2;
 220
 221   }
 222   if(j>=searchpoint)return(1);
 223
 224   return(-1);
 225 }
 226
 227 void _ve_envelope_shift(envelope_lookup *e,long shift){
 228   int i;
 229   for(i=0;i<e->ch*4;i++)
 230     memmove(e->filtered[i],e->filtered[i]+shift,(e->current-shift)*
 231             sizeof(float));
 232   e->current-=shift;
 233   e->lastmark-=shift;
 234 }
 235
 236