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 1.39 2001/12/12 09:45:24 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=e->winlength=ci->blocksizes[0]/2; /* not random */
  88   int i;
  89   e->minenergy=fromdB(gi->preecho_minenergy);
  90   e->iir=_ogg_calloc(ch*4,sizeof(*e->iir));
  91   e->filtered=_ogg_calloc(ch*4,sizeof(*e->filtered));
  92   e->ch=ch;
  93   e->storage=128;
  94   for(i=0;i<ch*4;i+=4){
  95
  96     IIR_init(e->iir+i,cheb_highpass_stages,cheb_highpass10k_gain,
  97              cheb_highpass10k_A,cheb_highpass_B);
  98     IIR_init(e->iir+i+1,cheb_bandpass_stages,cheb_bandpass6k_gain,
  99              cheb_bandpass6k_A,cheb_bandpass_B);
 100     IIR_init(e->iir+i+2,cheb_bandpass_stages,cheb_bandpass3k_gain,
 101              cheb_bandpass3k_A,cheb_bandpass_B);
 102     IIR_init(e->iir+i+3,cheb_bandpass_stages,cheb_bandpass1k_gain,
 103              cheb_bandpass1k_A,cheb_bandpass_B);
 104
 105     e->filtered[i]=_ogg_calloc(e->storage,sizeof(*e->filtered[i]));
 106     e->filtered[i+1]=_ogg_calloc(e->storage,sizeof(*e->filtered[i+1]));
 107     e->filtered[i+2]=_ogg_calloc(e->storage,sizeof(*e->filtered[i+2]));
 108     e->filtered[i+3]=_ogg_calloc(e->storage,sizeof(*e->filtered[i+3]));
 109   }
 110
 111 }
 112
 113 void _ve_envelope_clear(envelope_lookup *e){
 114   int i;
 115   for(i=0;i<e->ch*4;i++){
 116     IIR_clear((e->iir+i));
 117     _ogg_free(e->filtered[i]);
 118   }
 119   _ogg_free(e->filtered);
 120   _ogg_free(e->iir);
 121   memset(e,0,sizeof(*e));
 122 }
 123
 124 /* straight threshhold based until we find something that works better
 125    and isn't patented */
 126 static float _ve_deltai(envelope_lookup *ve,float *pre,float *post){
 127   long n=ve->winlength;
 128
 129   long i;
 130
 131   /* we want to have a 'minimum bar' for energy, else we're just
 132      basing blocks on quantization noise that outweighs the signal
 133      itself (for low power signals) */
 134
 135   float minV=ve->minenergy;
 136   float A=minV*minV*n;
 137   float B=A;
 138
 139   for(i=0;i<n;i++){
 140     A+=pre[i]*pre[i];
 141     B+=post[i]*post[i];
 142   }
 143
 144   A=todB(&A);
 145   B=todB(&B);
 146
 147   return(B-A);
 148 }
 149
 150 long _ve_envelope_search(vorbis_dsp_state *v){
 151   vorbis_info *vi=v->vi;
 152   codec_setup_info *ci=vi->codec_setup;
 153   vorbis_info_psy_global *gi=&ci->psy_g_param;
 154   envelope_lookup *ve=((backend_lookup_state *)(v->backend_state))->ve;
 155   long i,j,k;
 156
 157   /* make sure we have enough storage to match the PCM */
 158   if(v->pcm_storage>ve->storage){
 159     ve->storage=v->pcm_storage;
 160     for(i=0;i<ve->ch*4;i++)
 161       ve->filtered[i]=_ogg_realloc(ve->filtered[i],ve->storage*sizeof(*ve->filtered[i]));
 162   }
 163
 164   /* catch up the highpass to match the pcm */
 165   for(i=0;i<ve->ch;i++){
 166     float *pcm=v->pcm[i];
 167     float *filtered0=ve->filtered[i*4];
 168     float *filtered1=ve->filtered[i*4+1];
 169     float *filtered2=ve->filtered[i*4+2];
 170     float *filtered3=ve->filtered[i*4+3];
 171     IIR_state *iir0=ve->iir+i*4;
 172     IIR_state *iir1=ve->iir+i*4+1;
 173     IIR_state *iir2=ve->iir+i*4+2;
 174     IIR_state *iir3=ve->iir+i*4+3;
 175     int flag=1;
 176     for(j=ve->current;j<v->pcm_current;j++){
 177       filtered0[j]=IIR_filter(iir0,pcm[j]);
 178       filtered1[j]=IIR_filter_Band(iir1,pcm[j]);
 179       filtered2[j]=IIR_filter_Band(iir2,pcm[j]);
 180       filtered3[j]=IIR_filter_Band(iir3,pcm[j]);
 181       if(pcm[j])flag=0;
 182     }
 183     if(flag && ve->current+64<v->pcm_current){
 184       IIR_reset(iir0);
 185       IIR_reset(iir1);
 186       IIR_reset(iir2);
 187       IIR_reset(iir3);
 188     }
 189
 190   }
 191
 192   ve->current=v->pcm_current;
 193
 194   {
 195     int flag=-1;
 196     long centerW=v->centerW;
 197     long beginW=centerW-ci->blocksizes[v->W]/4;
 198     //long endW=centerW+ci->blocksizes[v->W]/4+ci->blocksizes[0]/4;
 199     long testW=centerW+ci->blocksizes[v->W]/4+ci->blocksizes[1]/2+ci->blocksizes[0]/4;
 200     if(v->W)
 201       beginW-=ci->blocksizes[v->lW]/4;
 202     else
 203       beginW-=ci->blocksizes[0]/4;
 204
 205     if(ve->mark>=centerW && ve->mark<testW)return(0);
 206     if(ve->mark>=testW)return(1);
 207
 208     if(v->W)
 209       j=ve->cursor;
 210     else
 211       j=centerW-ci->blocksizes[0]/4;
 212
 213     while(j+ve->winlength*3/2<=v->pcm_current){
 214       if(j>=testW)return(1);
 215       ve->cursor=j;
 216
 217       for(i=0;i<ve->ch;i++){
 218         for(k=0;k<4;k++){
 219           float *filtered=ve->filtered[i*4+k]+j;
 220           float *filtered2=ve->filtered[i*4+k]+j+ve->winlength/2;
 221           float m=_ve_deltai(ve,filtered-ve->winlength,filtered);
 222           float mm=_ve_deltai(ve,filtered2-ve->winlength,filtered2);
 223
 224           if(m>gi->preecho_thresh[k] || m<gi->postecho_thresh[k]){
 225             if(j<=centerW){
 226               ve->prevmark=ve->mark=j;
 227             }else{
 228               /* if a quarter-short-block advance is an even stronger
 229                  reading, set *that* as the impulse point. */
 230               if((m>0. && mm>m) || (m<0. && mm<m))
 231                 flag=j+ve->winlength/2;
 232               else
 233                 if(flag<0)flag=j;
 234             }
 235           }
 236         }
 237       }
 238
 239       if(flag>=0){
 240         ve->prevmark=ve->mark;
 241         ve->mark=flag;
 242         if(flag>=testW)return(1);
 243         return(0);
 244       }
 245
 246       j+=ve->winlength/2;
 247     }
 248   }
 249
 250   return(-1);
 251 }
 252
 253 int _ve_envelope_mark(vorbis_dsp_state *v){
 254   envelope_lookup *ve=((backend_lookup_state *)(v->backend_state))->ve;
 255   vorbis_info *vi=v->vi;
 256   codec_setup_info *ci=vi->codec_setup;
 257   long centerW=v->centerW;
 258   long beginW=centerW-ci->blocksizes[v->W]/4;
 259   long endW=centerW+ci->blocksizes[v->W]/4;
 260   if(v->W){
 261     beginW-=ci->blocksizes[v->lW]/4;
 262     endW+=ci->blocksizes[v->nW]/4;
 263   }else{
 264     beginW-=ci->blocksizes[0]/4;
 265     endW+=ci->blocksizes[0]/4;
 266   }
 267
 268   if(ve->prevmark>=beginW && ve->prevmark<endW)return(1);
 269   if(ve->mark>=beginW && ve->mark<endW)return(1);
 270   return(0);
 271 }
 272
 273 void _ve_envelope_shift(envelope_lookup *e,long shift){
 274   int i;
 275   for(i=0;i<e->ch*4;i++)
 276     memmove(e->filtered[i],e->filtered[i]+shift,(e->current-shift)*
 277             sizeof(*e->filtered[i]));
 278   e->current-=shift;
 279   if(e->prevmark>=0)
 280     e->prevmark-=shift;
 281   if(e->mark>=0)
 282     e->mark-=shift;
 283   e->cursor-=shift;
 284 }
 285
 286