libvorbis-1.0.1/lib/envelope.c

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   8  * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2002             *
   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 1.54 2003/09/05 23:17:49 giles 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=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 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].markers[pos]=valmax;*/
 196       filters[j].ampbuf[this]=acc;
 197       filters[j].ampptr++;
 198       if(filters[j].ampptr>=VE_AMP)filters[j].ampptr=0;
 199     }
 200
 201     /* look at min/max, decide trigger */
 202     if(valmax>gi->preecho_thresh[j]+penalty){
 203       ret|=1;
 204       ret|=4;
 205     }
 206     if(valmin<gi->postecho_thresh[j]-penalty)ret|=2;
 207   }
 208
 209   return(ret);
 210 }
 211
 212 #if 0
 213 static int seq=0;
 214 static ogg_int64_t totalshift=-1024;
 215 #endif
 216
 217 long _ve_envelope_search(vorbis_dsp_state *v){
 218   vorbis_info *vi=v->vi;
 219   codec_setup_info *ci=vi->codec_setup;
 220   vorbis_info_psy_global *gi=&ci->psy_g_param;
 221   envelope_lookup *ve=((private_state *)(v->backend_state))->ve;
 222   long i,j;
 223
 224   int first=ve->current/ve->searchstep;
 225   int last=v->pcm_current/ve->searchstep-VE_WIN;
 226   if(first<0)first=0;
 227
 228   /* make sure we have enough storage to match the PCM */
 229   if(last+VE_WIN+VE_POST>ve->storage){
 230     ve->storage=last+VE_WIN+VE_POST; /* be sure */
 231     ve->mark=_ogg_realloc(ve->mark,ve->storage*sizeof(*ve->mark));
 232   }
 233
 234   for(j=first;j<last;j++){
 235     int ret=0;
 236
 237     ve->stretch++;
 238     if(ve->stretch>VE_MAXSTRETCH*2)
 239       ve->stretch=VE_MAXSTRETCH*2;
 240
 241     for(i=0;i<ve->ch;i++){
 242       float *pcm=v->pcm[i]+ve->searchstep*(j);
 243       ret|=_ve_amp(ve,gi,pcm,ve->band,ve->filter+i*VE_BANDS,j);
 244     }
 245
 246     ve->mark[j+VE_POST]=0;
 247     if(ret&1){
 248       ve->mark[j]=1;
 249       ve->mark[j+1]=1;
 250     }
 251
 252     if(ret&2){
 253       ve->mark[j]=1;
 254       if(j>0)ve->mark[j-1]=1;
 255     }
 256
 257     if(ret&4)ve->stretch=-1;
 258   }
 259
 260   ve->current=last*ve->searchstep;
 261
 262   {
 263     long centerW=v->centerW;
 264     long testW=
 265       centerW+
 266       ci->blocksizes[v->W]/4+
 267       ci->blocksizes[1]/2+
 268       ci->blocksizes[0]/4;
 269
 270     j=ve->cursor;
 271
 272     while(j<ve->current-(ve->searchstep)){/* account for postecho
 273                                              working back one window */
 274       if(j>=testW)return(1);
 275
 276       ve->cursor=j;
 277
 278       if(ve->mark[j/ve->searchstep]){
 279         if(j>centerW){
 280
 281           #if 0
 282           if(j>ve->curmark){
 283             float *marker=alloca(v->pcm_current*sizeof(*marker));
 284             int l,m;
 285             memset(marker,0,sizeof(*marker)*v->pcm_current);
 286             fprintf(stderr,"mark! seq=%d, cursor:%fs time:%fs\n",
 287                     seq,
 288                     (totalshift+ve->cursor)/44100.,
 289                     (totalshift+j)/44100.);
 290             _analysis_output_always("pcmL",seq,v->pcm[0],v->pcm_current,0,0,totalshift);
 291             _analysis_output_always("pcmR",seq,v->pcm[1],v->pcm_current,0,0,totalshift);
 292
 293             _analysis_output_always("markL",seq,v->pcm[0],j,0,0,totalshift);
 294             _analysis_output_always("markR",seq,v->pcm[1],j,0,0,totalshift);
 295
 296             for(m=0;m<VE_BANDS;m++){
 297               char buf[80];
 298               sprintf(buf,"delL%d",m);
 299               for(l=0;l<last;l++)marker[l*ve->searchstep]=ve->filter[m].markers[l]*.1;
 300               _analysis_output_always(buf,seq,marker,v->pcm_current,0,0,totalshift);
 301             }
 302
 303             for(m=0;m<VE_BANDS;m++){
 304               char buf[80];
 305               sprintf(buf,"delR%d",m);
 306               for(l=0;l<last;l++)marker[l*ve->searchstep]=ve->filter[m+VE_BANDS].markers[l]*.1;
 307               _analysis_output_always(buf,seq,marker,v->pcm_current,0,0,totalshift);
 308             }
 309
 310             for(l=0;l<last;l++)marker[l*ve->searchstep]=ve->mark[l]*.4;
 311             _analysis_output_always("mark",seq,marker,v->pcm_current,0,0,totalshift);
 312
 313
 314             seq++;
 315
 316           }
 317 #endif
 318
 319           ve->curmark=j;
 320           if(j>=testW)return(1);
 321           return(0);
 322         }
 323       }
 324       j+=ve->searchstep;
 325     }
 326   }
 327
 328   return(-1);
 329 }
 330
 331 int _ve_envelope_mark(vorbis_dsp_state *v){
 332   envelope_lookup *ve=((private_state *)(v->backend_state))->ve;
 333   vorbis_info *vi=v->vi;
 334   codec_setup_info *ci=vi->codec_setup;
 335   long centerW=v->centerW;
 336   long beginW=centerW-ci->blocksizes[v->W]/4;
 337   long endW=centerW+ci->blocksizes[v->W]/4;
 338   if(v->W){
 339     beginW-=ci->blocksizes[v->lW]/4;
 340     endW+=ci->blocksizes[v->nW]/4;
 341   }else{
 342     beginW-=ci->blocksizes[0]/4;
 343     endW+=ci->blocksizes[0]/4;
 344   }
 345
 346   if(ve->curmark>=beginW && ve->curmark<endW)return(1);
 347   {
 348     long first=beginW/ve->searchstep;
 349     long last=endW/ve->searchstep;
 350     long i;
 351     for(i=first;i<last;i++)
 352       if(ve->mark[i])return(1);
 353   }
 354   return(0);
 355 }
 356
 357 void _ve_envelope_shift(envelope_lookup *e,long shift){
 358   int smallsize=e->current/e->searchstep+VE_POST; /* adjust for placing marks
 359                                                      ahead of ve->current */
 360   int smallshift=shift/e->searchstep;
 361
 362   memmove(e->mark,e->mark+smallshift,(smallsize-smallshift)*sizeof(*e->mark));
 363
 364   #if 0
 365   for(i=0;i<VE_BANDS*e->ch;i++)
 366     memmove(e->filter[i].markers,
 367             e->filter[i].markers+smallshift,
 368             (1024-smallshift)*sizeof(*(*e->filter).markers));
 369   totalshift+=shift;
 370   #endif
 371
 372   e->current-=shift;
 373   if(e->curmark>=0)
 374     e->curmark-=shift;
 375   e->cursor-=shift;
 376 }
 377
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