lib/envelope.c

   1 /********************************************************************
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   3  * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE.   *
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   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
  14  last mod: $Id: envelope.c,v 1.48 2002/04/01 00:49:41 xiphmont Exp $
  15
  16  ********************************************************************/
  17
  18 #include <stdlib.h>
  19 #include <string.h>
  20 #include <stdio.h>
  21 #include <math.h>
  22 #include <ogg/ogg.h>
  23 #include "vorbis/codec.h"
  24 #include "codec_internal.h"
  25
  26 #include "os.h"
  27 #include "scales.h"
  28 #include "envelope.h"
  29 #include "mdct.h"
  30 #include "misc.h"
  31
  32 void _ve_envelope_init(envelope_lookup *e,vorbis_info *vi){
  33   codec_setup_info *ci=vi->codec_setup;
  34   vorbis_info_psy_global *gi=&ci->psy_g_param;
  35   int ch=vi->channels;
  36   int i,j;
  37   int n=e->winlength=128;
  38   e->searchstep=64; /* not random */
  39
  40   e->minenergy=gi->preecho_minenergy;
  41   e->ch=ch;
  42   e->storage=128;
  43   e->cursor=ci->blocksizes[1]/2;
  44   e->mdct_win=_ogg_calloc(n,sizeof(*e->mdct_win));
  45   mdct_init(&e->mdct,n);
  46
  47   for(i=0;i<n;i++){
  48     e->mdct_win[i]=sin(i/(n-1.)*M_PI);
  49     e->mdct_win[i]*=e->mdct_win[i];
  50   }
  51
  52   /* magic follows */
  53   e->band[0].begin=2;  e->band[0].end=4;
  54   e->band[1].begin=4;  e->band[1].end=8;
  55   e->band[2].begin=6;  e->band[2].end=10;
  56   e->band[3].begin=12; e->band[3].end=12;
  57   e->band[4].begin=18; e->band[4].end=16;
  58   e->band[5].begin=26; e->band[5].end=20;
  59   e->band[6].begin=36; e->band[6].end=24;
  60
  61   for(j=0;j<VE_BANDS;j++){
  62     n=e->band[j].end;
  63     e->band[j].window=_ogg_malloc(n*sizeof(*e->band[0].window));
  64     for(i=0;i<n;i++){
  65       e->band[j].window[i]=sin((i+.5)/n*M_PI);
  66       e->band[j].total+=e->band[j].window[i];
  67     }
  68     e->band[j].total=1./e->band[j].total;
  69   }
  70
  71   e->filter=_ogg_calloc(VE_BANDS*ch,sizeof(*e->filter));
  72   e->mark=_ogg_calloc(e->storage,sizeof(*e->mark));
  73
  74 }
  75
  76 void _ve_envelope_clear(envelope_lookup *e){
  77   int i;
  78   mdct_clear(&e->mdct);
  79   for(i=0;i<VE_BANDS;i++)
  80     _ogg_free(e->band[i].window);
  81   _ogg_free(e->mdct_win);
  82   _ogg_free(e->filter);
  83   _ogg_free(e->mark);
  84   memset(e,0,sizeof(*e));
  85 }
  86
  87 /* fairly straight threshhold-by-band based until we find something
  88    that works better and isn't patented. */
  89
  90 static int _ve_amp(envelope_lookup *ve,
  91                    vorbis_info_psy_global *gi,
  92                    float *data,
  93                    envelope_band *bands,
  94                    envelope_filter_state *filters,
  95                    long pos){
  96   long n=ve->winlength;
  97   int ret=0;
  98   long i,j;
  99   float decay;
 100
 101   /* we want to have a 'minimum bar' for energy, else we're just
 102      basing blocks on quantization noise that outweighs the signal
 103      itself (for low power signals) */
 104
 105   float minV=ve->minenergy;
 106   float *vec=alloca(n*sizeof(*vec));
 107
 108   /* stretch is used to gradually lengthen the number of windows
 109      considered prevoius-to-potential-trigger */
 110   int stretch=max(VE_MINSTRETCH,ve->stretch/2);
 111   float penalty=gi->stretch_penalty-(ve->stretch/2-VE_MINSTRETCH);
 112   if(penalty<0.f)penalty=0.f;
 113   if(penalty>gi->stretch_penalty)penalty=gi->stretch_penalty;
 114
 115   /*_analysis_output_always("lpcm",seq2,data,n,0,0,
 116     totalshift+pos*ve->searchstep);*/
 117
 118  /* window and transform */
 119   for(i=0;i<n;i++)
 120     vec[i]=data[i]*ve->mdct_win[i];
 121   mdct_forward(&ve->mdct,vec,vec);
 122
 123   /*_analysis_output_always("mdct",seq2,vec,n/2,0,1,0); */
 124
 125   /* near-DC spreading function; this has nothing to do with
 126      psychoacoustics, just sidelobe leakage and window size */
 127   {
 128     float temp=vec[0]*vec[0]+.7*vec[1]*vec[1]+.2*vec[2]*vec[2];
 129     int ptr=filters->nearptr;
 130
 131     /* the accumulation is regularly refreshed from scratch to avoid
 132        floating point creep */
 133     if(ptr==0){
 134       decay=filters->nearDC_acc=filters->nearDC_partialacc+temp;
 135       filters->nearDC_partialacc=temp;
 136     }else{
 137       decay=filters->nearDC_acc+=temp;
 138       filters->nearDC_partialacc+=temp;
 139     }
 140     filters->nearDC_acc-=filters->nearDC[ptr];
 141     filters->nearDC[ptr]=temp;
 142
 143     decay*=(1./(VE_NEARDC+1));
 144     filters->nearptr++;
 145     if(filters->nearptr>=VE_NEARDC)filters->nearptr=0;
 146     decay=todB(&decay)*.5-15.f;
 147   }
 148
 149   /* perform spreading and limiting, also smooth the spectrum.  yes,
 150      the MDCT results in all real coefficients, but it still *behaves*
 151      like real/imaginary pairs */
 152   for(i=0;i<n/2;i+=2){
 153     float val=vec[i]*vec[i]+vec[i+1]*vec[i+1];
 154     val=todB(&val)*.5f;
 155     if(val<decay)val=decay;
 156     if(val<minV)val=minV;
 157     vec[i>>1]=val;
 158     decay-=8.;
 159   }
 160
 161   /*_analysis_output_always("spread",seq2++,vec,n/4,0,0,0);*/
 162
 163   /* perform preecho/postecho triggering by band */
 164   for(j=0;j<VE_BANDS;j++){
 165     float acc=0.;
 166     float valmax,valmin;
 167
 168     /* accumulate amplitude */
 169     for(i=0;i<bands[j].end;i++)
 170       acc+=vec[i+bands[j].begin]*bands[j].window[i];
 171
 172     acc*=bands[j].total;
 173
 174     /* convert amplitude to delta */
 175     {
 176       int p,this=filters[j].ampptr;
 177       float postmax,postmin,premax=-99999.f,premin=99999.f;
 178
 179       p=this;
 180       p--;
 181       if(p<0)p+=VE_AMP;
 182       postmax=max(acc,filters[j].ampbuf[p]);
 183       postmin=min(acc,filters[j].ampbuf[p]);
 184
 185       for(i=0;i<stretch;i++){
 186         p--;
 187         if(p<0)p+=VE_AMP;
 188         premax=max(premax,filters[j].ampbuf[p]);
 189         premin=min(premin,filters[j].ampbuf[p]);
 190       }
 191
 192       valmin=postmin-premin;
 193       valmax=postmax-premax;
 194
 195       filters[j].ampbuf[this]=acc;
 196       filters[j].ampptr++;
 197       if(filters[j].ampptr>=VE_AMP)filters[j].ampptr=0;
 198     }
 199
 200     /* look at min/max, decide trigger */
 201     if(valmax>gi->preecho_thresh[j]+penalty){
 202       ret|=1;
 203       ret|=4;
 204     }
 205     if(valmin<gi->postecho_thresh[j]-penalty)ret|=2;
 206   }
 207
 208   return(ret);
 209 }
 210
 211 long _ve_envelope_search(vorbis_dsp_state *v){
 212   vorbis_info *vi=v->vi;
 213   codec_setup_info *ci=vi->codec_setup;
 214   vorbis_info_psy_global *gi=&ci->psy_g_param;
 215   envelope_lookup *ve=((backend_lookup_state *)(v->backend_state))->ve;
 216   long i,j;
 217
 218   int first=ve->current/ve->searchstep;
 219   int last=v->pcm_current/ve->searchstep-VE_WIN;
 220   if(first<0)first=0;
 221
 222   /* make sure we have enough storage to match the PCM */
 223   if(last>ve->storage){
 224     ve->storage=last+VE_WIN;
 225     ve->mark=_ogg_realloc(ve->mark,ve->storage*sizeof(*ve->mark));
 226   }
 227
 228   for(j=first;j<last;j++){
 229     int ret=0;
 230
 231     ve->stretch++;
 232     if(ve->stretch>VE_MAXSTRETCH*2)
 233       ve->stretch=VE_MAXSTRETCH*2;
 234
 235     for(i=0;i<ve->ch;i++){
 236       float *pcm=v->pcm[i]+ve->searchstep*(j);
 237       ret|=_ve_amp(ve,gi,pcm,ve->band,ve->filter+i*VE_BANDS,j);
 238     }
 239
 240     ve->mark[j+VE_POST]=0;
 241     if(ret&1){
 242       ve->mark[j]=1;
 243       ve->mark[j+1]=1;
 244     }
 245
 246     if(ret&2){
 247       ve->mark[j]=1;
 248       if(j>0)ve->mark[j-1]=1;
 249     }
 250
 251     if(ret&4)ve->stretch=-1;
 252   }
 253
 254   ve->current=last*ve->searchstep;
 255
 256   {
 257     long centerW=v->centerW;
 258     long testW=
 259       centerW+
 260       ci->blocksizes[v->W]/4+
 261       ci->blocksizes[1]/2+
 262       ci->blocksizes[0]/4;
 263
 264     j=ve->cursor;
 265
 266     while(j<ve->current-(ve->searchstep)){/* account for postecho
 267                                              working back one window */
 268       if(j>=testW)return(1);
 269
 270       ve->cursor=j;
 271
 272       if(ve->mark[j/ve->searchstep]){
 273         if(j>centerW){
 274
 275           #if 0
 276           if(j>ve->curmark){
 277             float *marker=alloca(v->pcm_current*sizeof(*marker));
 278             int l,m;
 279             memset(marker,0,sizeof(*marker)*v->pcm_current);
 280             fprintf(stderr,"mark! seq=%d, cursor:%fs time:%fs\n",
 281                     seq,
 282                     (totalshift+ve->cursor)/44100.,
 283                     (totalshift+j)/44100.);
 284             _analysis_output_always("pcmL",seq,v->pcm[0],v->pcm_current,0,0,totalshift);
 285             _analysis_output_always("pcmR",seq,v->pcm[1],v->pcm_current,0,0,totalshift);
 286
 287             _analysis_output_always("markL",seq,v->pcm[0],j,0,0,totalshift);
 288             _analysis_output_always("markR",seq,v->pcm[1],j,0,0,totalshift);
 289
 290             for(m=0;m<VE_BANDS;m++){
 291               char buf[80];
 292               sprintf(buf,"delL%d",m);
 293               for(l=0;l<last;l++)marker[l*ve->searchstep]=ve->filter[m].markers[l]*.1;
 294               _analysis_output_always(buf,seq,marker,v->pcm_current,0,0,totalshift);
 295             }
 296
 297             for(m=0;m<VE_BANDS;m++){
 298               char buf[80];
 299               sprintf(buf,"delR%d",m);
 300               for(l=0;l<last;l++)marker[l*ve->searchstep]=ve->filter[m+VE_BANDS].markers[l]*.1;
 301               _analysis_output_always(buf,seq,marker,v->pcm_current,0,0,totalshift);
 302             }
 303
 304
 305             for(l=0;l<last;l++)marker[l*ve->searchstep]=ve->stretchm[l]*.1;
 306             _analysis_output_always("stretch",seq,marker,v->pcm_current,0,0,totalshift);
 307
 308             seq++;
 309
 310           }
 311           #endif
 312
 313           ve->curmark=j;
 314           if(j>=testW)return(1);
 315           return(0);
 316         }
 317       }
 318       j+=ve->searchstep;
 319     }
 320   }
 321
 322   return(-1);
 323 }
 324
 325 int _ve_envelope_mark(vorbis_dsp_state *v){
 326   envelope_lookup *ve=((backend_lookup_state *)(v->backend_state))->ve;
 327   vorbis_info *vi=v->vi;
 328   codec_setup_info *ci=vi->codec_setup;
 329   long centerW=v->centerW;
 330   long beginW=centerW-ci->blocksizes[v->W]/4;
 331   long endW=centerW+ci->blocksizes[v->W]/4;
 332   if(v->W){
 333     beginW-=ci->blocksizes[v->lW]/4;
 334     endW+=ci->blocksizes[v->nW]/4;
 335   }else{
 336     beginW-=ci->blocksizes[0]/4;
 337     endW+=ci->blocksizes[0]/4;
 338   }
 339
 340   if(ve->curmark>=beginW && ve->curmark<endW)return(1);
 341   {
 342     long first=beginW/ve->searchstep;
 343     long last=endW/ve->searchstep;
 344     long i;
 345     for(i=first;i<last;i++)
 346       if(ve->mark[i])return(1);
 347   }
 348   return(0);
 349 }
 350
 351 void _ve_envelope_shift(envelope_lookup *e,long shift){
 352   int smallsize=e->current/e->searchstep;
 353   int smallshift=shift/e->searchstep;
 354   int i;
 355
 356   memmove(e->mark,e->mark+smallshift,(smallsize-smallshift)*sizeof(*e->mark));
 357
 358 #if 0
 359   for(i=0;i<VE_BANDS*e->ch;i++)
 360     memmove(e->filter[i].markers,
 361             e->filter[i].markers+smallshift,
 362             (1024-smallshift)*sizeof(*(*e->filter).markers));
 363   memmove(e->stretchm,e->stretchm+smallshift,(smallsize-smallshift)*sizeof(*e->stretchm));
 364   totalshift+=shift;
 365 #endif
 366
 367   e->current-=shift;
 368   if(e->curmark>=0)
 369     e->curmark-=shift;
 370   e->cursor-=shift;
 371 }
 372
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