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 1994-2009             *
   9  * by the Xiph.Org Foundation https://xiph.org/                     *
  10  *                                                                  *
  11  ********************************************************************
  12
  13  function: PCM data envelope analysis
  14
  15  ********************************************************************/
  16
  17 #include <stdlib.h>
  18 #include <string.h>
  19 #include <stdio.h>
  20 #include <math.h>
  21 #include <ogg/ogg.h>
  22 #include "vorbis/codec.h"
  23 #include "codec_internal.h"
  24
  25 #include "os.h"
  26 #include "scales.h"
  27 #include "envelope.h"
  28 #include "mdct.h"
  29 #include "misc.h"
  30
  31 void _ve_envelope_init(envelope_lookup *e,vorbis_info *vi){
  32   codec_setup_info *ci=vi->codec_setup;
  33   vorbis_info_psy_global *gi=&ci->psy_g_param;
  34   int ch=vi->channels;
  35   int i,j;
  36   int n=e->winlength=128;
  37   e->searchstep=64; /* not random */
  38
  39   e->minenergy=gi->preecho_minenergy;
  40   e->ch=ch;
  41   e->storage=128;
  42   e->cursor=ci->blocksizes[1]/2;
  43   e->mdct_win=_ogg_calloc(n,sizeof(*e->mdct_win));
  44   mdct_init(&e->mdct,n);
  45
  46   for(i=0;i<n;i++){
  47     e->mdct_win[i]=sin(i/(n-1.)*M_PI);
  48     e->mdct_win[i]*=e->mdct_win[i];
  49   }
  50
  51   /* magic follows */
  52   e->band[0].begin=2;  e->band[0].end=4;
  53   e->band[1].begin=4;  e->band[1].end=5;
  54   e->band[2].begin=6;  e->band[2].end=6;
  55   e->band[3].begin=9;  e->band[3].end=8;
  56   e->band[4].begin=13;  e->band[4].end=8;
  57   e->band[5].begin=17;  e->band[5].end=8;
  58   e->band[6].begin=22;  e->band[6].end=8;
  59
  60   for(j=0;j<VE_BANDS;j++){
  61     n=e->band[j].end;
  62     e->band[j].window=_ogg_malloc(n*sizeof(*e->band[0].window));
  63     for(i=0;i<n;i++){
  64       e->band[j].window[i]=sin((i+.5)/n*M_PI);
  65       e->band[j].total+=e->band[j].window[i];
  66     }
  67     e->band[j].total=1./e->band[j].total;
  68   }
  69
  70   e->filter=_ogg_calloc(VE_BANDS*ch,sizeof(*e->filter));
  71   e->mark=_ogg_calloc(e->storage,sizeof(*e->mark));
  72
  73 }
  74
  75 void _ve_envelope_clear(envelope_lookup *e){
  76   int i;
  77   mdct_clear(&e->mdct);
  78   for(i=0;i<VE_BANDS;i++)
  79     _ogg_free(e->band[i].window);
  80   _ogg_free(e->mdct_win);
  81   _ogg_free(e->filter);
  82   _ogg_free(e->mark);
  83   memset(e,0,sizeof(*e));
  84 }
  85
  86 /* fairly straight threshhold-by-band based until we find something
  87    that works better and isn't patented. */
  88
  89 static int _ve_amp(envelope_lookup *ve,
  90                    vorbis_info_psy_global *gi,
  91                    float *data,
  92                    envelope_band *bands,
  93                    envelope_filter_state *filters){
  94   long n=ve->winlength;
  95   int ret=0;
  96   long i,j;
  97   float decay;
  98
  99   /* we want to have a 'minimum bar' for energy, else we're just
 100      basing blocks on quantization noise that outweighs the signal
 101      itself (for low power signals) */
 102
 103   float minV=ve->minenergy;
 104   float *vec=alloca(n*sizeof(*vec));
 105
 106   /* stretch is used to gradually lengthen the number of windows
 107      considered prevoius-to-potential-trigger */
 108   int stretch=max(VE_MINSTRETCH,ve->stretch/2);
 109   float penalty=gi->stretch_penalty-(ve->stretch/2-VE_MINSTRETCH);
 110   if(penalty<0.f)penalty=0.f;
 111   if(penalty>gi->stretch_penalty)penalty=gi->stretch_penalty;
 112
 113   /*_analysis_output_always("lpcm",seq2,data,n,0,0,
 114     totalshift+pos*ve->searchstep);*/
 115
 116  /* window and transform */
 117   for(i=0;i<n;i++)
 118     vec[i]=data[i]*ve->mdct_win[i];
 119   mdct_forward(&ve->mdct,vec,vec);
 120
 121   /*_analysis_output_always("mdct",seq2,vec,n/2,0,1,0); */
 122
 123   /* near-DC spreading function; this has nothing to do with
 124      psychoacoustics, just sidelobe leakage and window size */
 125   {
 126     float temp=vec[0]*vec[0]+.7*vec[1]*vec[1]+.2*vec[2]*vec[2];
 127     int ptr=filters->nearptr;
 128
 129     /* the accumulation is regularly refreshed from scratch to avoid
 130        floating point creep */
 131     if(ptr==0){
 132       decay=filters->nearDC_acc=filters->nearDC_partialacc+temp;
 133       filters->nearDC_partialacc=temp;
 134     }else{
 135       decay=filters->nearDC_acc+=temp;
 136       filters->nearDC_partialacc+=temp;
 137     }
 138     filters->nearDC_acc-=filters->nearDC[ptr];
 139     filters->nearDC[ptr]=temp;
 140
 141     decay*=(1./(VE_NEARDC+1));
 142     filters->nearptr++;
 143     if(filters->nearptr>=VE_NEARDC)filters->nearptr=0;
 144     decay=todB(&decay)*.5-15.f;
 145   }
 146
 147   /* perform spreading and limiting, also smooth the spectrum.  yes,
 148      the MDCT results in all real coefficients, but it still *behaves*
 149      like real/imaginary pairs */
 150   for(i=0;i<n/2;i+=2){
 151     float val=vec[i]*vec[i]+vec[i+1]*vec[i+1];
 152     val=todB(&val)*.5f;
 153     if(val<decay)val=decay;
 154     if(val<minV)val=minV;
 155     vec[i>>1]=val;
 156     decay-=8.;
 157   }
 158
 159   /*_analysis_output_always("spread",seq2++,vec,n/4,0,0,0);*/
 160
 161   /* perform preecho/postecho triggering by band */
 162   for(j=0;j<VE_BANDS;j++){
 163     float acc=0.;
 164     float valmax,valmin;
 165
 166     /* accumulate amplitude */
 167     for(i=0;i<bands[j].end;i++)
 168       acc+=vec[i+bands[j].begin]*bands[j].window[i];
 169
 170     acc*=bands[j].total;
 171
 172     /* convert amplitude to delta */
 173     {
 174       int p,this=filters[j].ampptr;
 175       float postmax,postmin,premax=-99999.f,premin=99999.f;
 176
 177       p=this;
 178       p--;
 179       if(p<0)p+=VE_AMP;
 180       postmax=max(acc,filters[j].ampbuf[p]);
 181       postmin=min(acc,filters[j].ampbuf[p]);
 182
 183       for(i=0;i<stretch;i++){
 184         p--;
 185         if(p<0)p+=VE_AMP;
 186         premax=max(premax,filters[j].ampbuf[p]);
 187         premin=min(premin,filters[j].ampbuf[p]);
 188       }
 189
 190       valmin=postmin-premin;
 191       valmax=postmax-premax;
 192
 193       /*filters[j].markers[pos]=valmax;*/
 194       filters[j].ampbuf[this]=acc;
 195       filters[j].ampptr++;
 196       if(filters[j].ampptr>=VE_AMP)filters[j].ampptr=0;
 197     }
 198
 199     /* look at min/max, decide trigger */
 200     if(valmax>gi->preecho_thresh[j]+penalty){
 201       ret|=1;
 202       ret|=4;
 203     }
 204     if(valmin<gi->postecho_thresh[j]-penalty)ret|=2;
 205   }
 206
 207   return(ret);
 208 }
 209
 210 #if 0
 211 static int seq=0;
 212 static ogg_int64_t totalshift=-1024;
 213 #endif
 214
 215 long _ve_envelope_search(vorbis_dsp_state *v){
 216   vorbis_info *vi=v->vi;
 217   codec_setup_info *ci=vi->codec_setup;
 218   vorbis_info_psy_global *gi=&ci->psy_g_param;
 219   envelope_lookup *ve=((private_state *)(v->backend_state))->ve;
 220   long i,j;
 221
 222   int first=ve->current/ve->searchstep;
 223   int last=v->pcm_current/ve->searchstep-VE_WIN;
 224   if(first<0)first=0;
 225
 226   /* make sure we have enough storage to match the PCM */
 227   if(last+VE_WIN+VE_POST>ve->storage){
 228     ve->storage=last+VE_WIN+VE_POST; /* be sure */
 229     ve->mark=_ogg_realloc(ve->mark,ve->storage*sizeof(*ve->mark));
 230   }
 231
 232   for(j=first;j<last;j++){
 233     int ret=0;
 234
 235     ve->stretch++;
 236     if(ve->stretch>VE_MAXSTRETCH*2)
 237       ve->stretch=VE_MAXSTRETCH*2;
 238
 239     for(i=0;i<ve->ch;i++){
 240       float *pcm=v->pcm[i]+ve->searchstep*(j);
 241       ret|=_ve_amp(ve,gi,pcm,ve->band,ve->filter+i*VE_BANDS);
 242     }
 243
 244     ve->mark[j+VE_POST]=0;
 245     if(ret&1){
 246       ve->mark[j]=1;
 247       ve->mark[j+1]=1;
 248     }
 249
 250     if(ret&2){
 251       ve->mark[j]=1;
 252       if(j>0)ve->mark[j-1]=1;
 253     }
 254
 255     if(ret&4)ve->stretch=-1;
 256   }
 257
 258   ve->current=last*ve->searchstep;
 259
 260   {
 261     long centerW=v->centerW;
 262     long testW=
 263       centerW+
 264       ci->blocksizes[v->W]/4+
 265       ci->blocksizes[1]/2+
 266       ci->blocksizes[0]/4;
 267
 268     j=ve->cursor;
 269
 270     while(j<ve->current-(ve->searchstep)){/* account for postecho
 271                                              working back one window */
 272       if(j>=testW)return(1);
 273
 274       ve->cursor=j;
 275
 276       if(ve->mark[j/ve->searchstep]){
 277         if(j>centerW){
 278
 279 #if 0
 280           if(j>ve->curmark){
 281             float *marker=alloca(v->pcm_current*sizeof(*marker));
 282             int l,m;
 283             memset(marker,0,sizeof(*marker)*v->pcm_current);
 284             fprintf(stderr,"mark! seq=%d, cursor:%fs time:%fs\n",
 285                     seq,
 286                     (totalshift+ve->cursor)/44100.,
 287                     (totalshift+j)/44100.);
 288             _analysis_output_always("pcmL",seq,v->pcm[0],v->pcm_current,0,0,totalshift);
 289             _analysis_output_always("pcmR",seq,v->pcm[1],v->pcm_current,0,0,totalshift);
 290
 291             _analysis_output_always("markL",seq,v->pcm[0],j,0,0,totalshift);
 292             _analysis_output_always("markR",seq,v->pcm[1],j,0,0,totalshift);
 293
 294             for(m=0;m<VE_BANDS;m++){
 295               char buf[80];
 296               sprintf(buf,"delL%d",m);
 297               for(l=0;l<last;l++)marker[l*ve->searchstep]=ve->filter[m].markers[l]*.1;
 298               _analysis_output_always(buf,seq,marker,v->pcm_current,0,0,totalshift);
 299             }
 300
 301             for(m=0;m<VE_BANDS;m++){
 302               char buf[80];
 303               sprintf(buf,"delR%d",m);
 304               for(l=0;l<last;l++)marker[l*ve->searchstep]=ve->filter[m+VE_BANDS].markers[l]*.1;
 305               _analysis_output_always(buf,seq,marker,v->pcm_current,0,0,totalshift);
 306             }
 307
 308             for(l=0;l<last;l++)marker[l*ve->searchstep]=ve->mark[l]*.4;
 309             _analysis_output_always("mark",seq,marker,v->pcm_current,0,0,totalshift);
 310
 311
 312             seq++;
 313
 314           }
 315 #endif
 316
 317           ve->curmark=j;
 318           if(j>=testW)return(1);
 319           return(0);
 320         }
 321       }
 322       j+=ve->searchstep;
 323     }
 324   }
 325
 326   return(-1);
 327 }
 328
 329 int _ve_envelope_mark(vorbis_dsp_state *v){
 330   envelope_lookup *ve=((private_state *)(v->backend_state))->ve;
 331   vorbis_info *vi=v->vi;
 332   codec_setup_info *ci=vi->codec_setup;
 333   long centerW=v->centerW;
 334   long beginW=centerW-ci->blocksizes[v->W]/4;
 335   long endW=centerW+ci->blocksizes[v->W]/4;
 336   if(v->W){
 337     beginW-=ci->blocksizes[v->lW]/4;
 338     endW+=ci->blocksizes[v->nW]/4;
 339   }else{
 340     beginW-=ci->blocksizes[0]/4;
 341     endW+=ci->blocksizes[0]/4;
 342   }
 343
 344   if(ve->curmark>=beginW && ve->curmark<endW)return(1);
 345   {
 346     long first=beginW/ve->searchstep;
 347     long last=endW/ve->searchstep;
 348     long i;
 349     for(i=first;i<last;i++)
 350       if(ve->mark[i])return(1);
 351   }
 352   return(0);
 353 }
 354
 355 void _ve_envelope_shift(envelope_lookup *e,long shift){
 356   int smallsize=e->current/e->searchstep+VE_POST; /* adjust for placing marks
 357                                                      ahead of ve->current */
 358   int smallshift=shift/e->searchstep;
 359
 360   memmove(e->mark,e->mark+smallshift,(smallsize-smallshift)*sizeof(*e->mark));
 361
 362 #if 0
 363   for(i=0;i<VE_BANDS*e->ch;i++)
 364     memmove(e->filter[i].markers,
 365             e->filter[i].markers+smallshift,
 366             (1024-smallshift)*sizeof(*(*e->filter).markers));
 367   totalshift+=shift;
 368 #endif
 369
 370   e->current-=shift;
 371   if(e->curmark>=0)
 372     e->curmark-=shift;
 373   e->cursor-=shift;
 374 }