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   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 http://www.xiph.org/                  *
  10  *                                                                  *
  11  ********************************************************************
  12
  13  function: PCM data envelope analysis
  14  last mod: $Id: envelope.c 16227 2009-07-08 06:58:46Z xiphmont $
  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=5;
  55   e->band[2].begin=6;  e->band[2].end=6;
  56   e->band[3].begin=9;  e->band[3].end=8;
  57   e->band[4].begin=13;  e->band[4].end=8;
  58   e->band[5].begin=17;  e->band[5].end=8;
  59   e->band[6].begin=22;  e->band[6].end=8;
  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 n=ve->winlength;
  96   int ret=0;
  97   long i,j;
  98   float decay;
  99
 100   /* we want to have a 'minimum bar' for energy, else we're just
 101      basing blocks on quantization noise that outweighs the signal
 102      itself (for low power signals) */
 103
 104   float minV=ve->minenergy;
 105   float *vec=alloca(n*sizeof(*vec));
 106
 107   /* stretch is used to gradually lengthen the number of windows
 108      considered prevoius-to-potential-trigger */
 109   int stretch=max(VE_MINSTRETCH,ve->stretch/2);
 110   float penalty=gi->stretch_penalty-(ve->stretch/2-VE_MINSTRETCH);
 111   if(penalty<0.f)penalty=0.f;
 112   if(penalty>gi->stretch_penalty)penalty=gi->stretch_penalty;
 113
 114   /*_analysis_output_always("lpcm",seq2,data,n,0,0,
 115     totalshift+pos*ve->searchstep);*/
 116
 117  /* window and transform */
 118   for(i=0;i<n;i++)
 119     vec[i]=data[i]*ve->mdct_win[i];
 120   mdct_forward(&ve->mdct,vec,vec);
 121
 122   /*_analysis_output_always("mdct",seq2,vec,n/2,0,1,0); */
 123
 124   /* near-DC spreading function; this has nothing to do with
 125      psychoacoustics, just sidelobe leakage and window size */
 126   {
 127     float temp=vec[0]*vec[0]+.7*vec[1]*vec[1]+.2*vec[2]*vec[2];
 128     int ptr=filters->nearptr;
 129
 130     /* the accumulation is regularly refreshed from scratch to avoid
 131        floating point creep */
 132     if(ptr==0){
 133       decay=filters->nearDC_acc=filters->nearDC_partialacc+temp;
 134       filters->nearDC_partialacc=temp;
 135     }else{
 136       decay=filters->nearDC_acc+=temp;
 137       filters->nearDC_partialacc+=temp;
 138     }
 139     filters->nearDC_acc-=filters->nearDC[ptr];
 140     filters->nearDC[ptr]=temp;
 141
 142     decay*=(1./(VE_NEARDC+1));
 143     filters->nearptr++;
 144     if(filters->nearptr>=VE_NEARDC)filters->nearptr=0;
 145     decay=todB(&decay)*.5-15.f;
 146   }
 147
 148   /* perform spreading and limiting, also smooth the spectrum.  yes,
 149      the MDCT results in all real coefficients, but it still *behaves*
 150      like real/imaginary pairs */
 151   for(i=0;i<n/2;i+=2){
 152     float val=vec[i]*vec[i]+vec[i+1]*vec[i+1];
 153     val=todB(&val)*.5f;
 154     if(val<decay)val=decay;
 155     if(val<minV)val=minV;
 156     vec[i>>1]=val;
 157     decay-=8.;
 158   }
 159
 160   /*_analysis_output_always("spread",seq2++,vec,n/4,0,0,0);*/
 161
 162   /* perform preecho/postecho triggering by band */
 163   for(j=0;j<VE_BANDS;j++){
 164     float acc=0.;
 165     float valmax,valmin;
 166
 167     /* accumulate amplitude */
 168     for(i=0;i<bands[j].end;i++)
 169       acc+=vec[i+bands[j].begin]*bands[j].window[i];
 170
 171     acc*=bands[j].total;
 172
 173     /* convert amplitude to delta */
 174     {
 175       int p,this=filters[j].ampptr;
 176       float postmax,postmin,premax=-99999.f,premin=99999.f;
 177
 178       p=this;
 179       p--;
 180       if(p<0)p+=VE_AMP;
 181       postmax=max(acc,filters[j].ampbuf[p]);
 182       postmin=min(acc,filters[j].ampbuf[p]);
 183
 184       for(i=0;i<stretch;i++){
 185         p--;
 186         if(p<0)p+=VE_AMP;
 187         premax=max(premax,filters[j].ampbuf[p]);
 188         premin=min(premin,filters[j].ampbuf[p]);
 189       }
 190
 191       valmin=postmin-premin;
 192       valmax=postmax-premax;
 193
 194       /*filters[j].markers[pos]=valmax;*/
 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 #if 0
 212 static int seq=0;
 213 static ogg_int64_t totalshift=-1024;
 214 #endif
 215
 216 long _ve_envelope_search(vorbis_dsp_state *v){
 217   vorbis_info *vi=v->vi;
 218   codec_setup_info *ci=vi->codec_setup;
 219   vorbis_info_psy_global *gi=&ci->psy_g_param;
 220   envelope_lookup *ve=((private_state *)(v->backend_state))->ve;
 221   long i,j;
 222
 223   int first=ve->current/ve->searchstep;
 224   int last=v->pcm_current/ve->searchstep-VE_WIN;
 225   if(first<0)first=0;
 226
 227   /* make sure we have enough storage to match the PCM */
 228   if(last+VE_WIN+VE_POST>ve->storage){
 229     ve->storage=last+VE_WIN+VE_POST; /* be sure */
 230     ve->mark=_ogg_realloc(ve->mark,ve->storage*sizeof(*ve->mark));
 231   }
 232
 233   for(j=first;j<last;j++){
 234     int ret=0;
 235
 236     ve->stretch++;
 237     if(ve->stretch>VE_MAXSTRETCH*2)
 238       ve->stretch=VE_MAXSTRETCH*2;
 239
 240     for(i=0;i<ve->ch;i++){
 241       float *pcm=v->pcm[i]+ve->searchstep*(j);
 242       ret|=_ve_amp(ve,gi,pcm,ve->band,ve->filter+i*VE_BANDS);
 243     }
 244
 245     ve->mark[j+VE_POST]=0;
 246     if(ret&1){
 247       ve->mark[j]=1;
 248       ve->mark[j+1]=1;
 249     }
 250
 251     if(ret&2){
 252       ve->mark[j]=1;
 253       if(j>0)ve->mark[j-1]=1;
 254     }
 255
 256     if(ret&4)ve->stretch=-1;
 257   }
 258
 259   ve->current=last*ve->searchstep;
 260
 261   {
 262     long centerW=v->centerW;
 263     long testW=
 264       centerW+
 265       ci->blocksizes[v->W]/4+
 266       ci->blocksizes[1]/2+
 267       ci->blocksizes[0]/4;
 268
 269     j=ve->cursor;
 270
 271     while(j<ve->current-(ve->searchstep)){/* account for postecho
 272                                              working back one window */
 273       if(j>=testW)return(1);
 274
 275       ve->cursor=j;
 276
 277       if(ve->mark[j/ve->searchstep]){
 278         if(j>centerW){
 279
 280 #if 0
 281           if(j>ve->curmark){
 282             float *marker=alloca(v->pcm_current*sizeof(*marker));
 283             int l,m;
 284             memset(marker,0,sizeof(*marker)*v->pcm_current);
 285             fprintf(stderr,"mark! seq=%d, cursor:%fs time:%fs\n",
 286                     seq,
 287                     (totalshift+ve->cursor)/44100.,
 288                     (totalshift+j)/44100.);
 289             _analysis_output_always("pcmL",seq,v->pcm[0],v->pcm_current,0,0,totalshift);
 290             _analysis_output_always("pcmR",seq,v->pcm[1],v->pcm_current,0,0,totalshift);
 291
 292             _analysis_output_always("markL",seq,v->pcm[0],j,0,0,totalshift);
 293             _analysis_output_always("markR",seq,v->pcm[1],j,0,0,totalshift);
 294
 295             for(m=0;m<VE_BANDS;m++){
 296               char buf[80];
 297               sprintf(buf,"delL%d",m);
 298               for(l=0;l<last;l++)marker[l*ve->searchstep]=ve->filter[m].markers[l]*.1;
 299               _analysis_output_always(buf,seq,marker,v->pcm_current,0,0,totalshift);
 300             }
 301
 302             for(m=0;m<VE_BANDS;m++){
 303               char buf[80];
 304               sprintf(buf,"delR%d",m);
 305               for(l=0;l<last;l++)marker[l*ve->searchstep]=ve->filter[m+VE_BANDS].markers[l]*.1;
 306               _analysis_output_always(buf,seq,marker,v->pcm_current,0,0,totalshift);
 307             }
 308
 309             for(l=0;l<last;l++)marker[l*ve->searchstep]=ve->mark[l]*.4;
 310             _analysis_output_always("mark",seq,marker,v->pcm_current,0,0,totalshift);
 311
 312
 313             seq++;
 314
 315           }
 316 #endif
 317
 318           ve->curmark=j;
 319           if(j>=testW)return(1);
 320           return(0);
 321         }
 322       }
 323       j+=ve->searchstep;
 324     }
 325   }
 326
 327   return(-1);
 328 }
 329
 330 int _ve_envelope_mark(vorbis_dsp_state *v){
 331   envelope_lookup *ve=((private_state *)(v->backend_state))->ve;
 332   vorbis_info *vi=v->vi;
 333   codec_setup_info *ci=vi->codec_setup;
 334   long centerW=v->centerW;
 335   long beginW=centerW-ci->blocksizes[v->W]/4;
 336   long endW=centerW+ci->blocksizes[v->W]/4;
 337   if(v->W){
 338     beginW-=ci->blocksizes[v->lW]/4;
 339     endW+=ci->blocksizes[v->nW]/4;
 340   }else{
 341     beginW-=ci->blocksizes[0]/4;
 342     endW+=ci->blocksizes[0]/4;
 343   }
 344
 345   if(ve->curmark>=beginW && ve->curmark<endW)return(1);
 346   {
 347     long first=beginW/ve->searchstep;
 348     long last=endW/ve->searchstep;
 349     long i;
 350     for(i=first;i<last;i++)
 351       if(ve->mark[i])return(1);
 352   }
 353   return(0);
 354 }
 355
 356 void _ve_envelope_shift(envelope_lookup *e,long shift){
 357   int smallsize=e->current/e->searchstep+VE_POST; /* adjust for placing marks
 358                                                      ahead of ve->current */
 359   int smallshift=shift/e->searchstep;
 360
 361   memmove(e->mark,e->mark+smallshift,(smallsize-smallshift)*sizeof(*e->mark));
 362
 363 #if 0
 364   for(i=0;i<VE_BANDS*e->ch;i++)
 365     memmove(e->filter[i].markers,
 366             e->filter[i].markers+smallshift,
 367             (1024-smallshift)*sizeof(*(*e->filter).markers));
 368   totalshift+=shift;
 369 #endif
 370
 371   e->current-=shift;
 372   if(e->curmark>=0)
 373     e->curmark-=shift;
 374   e->cursor-=shift;
 375 }