The Tor Browser: media/libvorbis/lib/vorbis_envelope.c@b8a032363ba2 (annotated)

media/libvorbis/lib/vorbis_envelope.c@b8a032363ba2 (annotated)

media/libvorbis/lib/vorbis_envelope.c

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /********************************************************************
  *                                                                  *
  * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE.   *
  * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *
  * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
  * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *
  *                                                                  *
  * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2009             *
  * by the Xiph.Org Foundation http://www.xiph.org/                  *
  *                                                                  *
  ********************************************************************
  function: PCM data envelope analysis
  last mod: $Id: envelope.c 16227 2009-07-08 06:58:46Z xiphmont $
  ********************************************************************/
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
 #include <math.h>
 #include <ogg/ogg.h>
 #include "vorbis/codec.h"
 #include "codec_internal.h"
 #include "os.h"
 #include "scales.h"
 #include "envelope.h"
 #include "mdct.h"
 #include "misc.h"
 void _ve_envelope_init(envelope_lookup *e,vorbis_info *vi){
   codec_setup_info *ci=vi->codec_setup;
   vorbis_info_psy_global *gi=&ci->psy_g_param;
   int ch=vi->channels;
   int i,j;
   int n=e->winlength=128;
   e->searchstep=64; /* not random */
   e->minenergy=gi->preecho_minenergy;
   e->ch=ch;
   e->storage=128;
   e->cursor=ci->blocksizes[1]/2;
   e->mdct_win=_ogg_calloc(n,sizeof(*e->mdct_win));
   mdct_init(&e->mdct,n);
   for(i=0;i<n;i++){
     e->mdct_win[i]=sin(i/(n-1.)*M_PI);
     e->mdct_win[i]*=e->mdct_win[i];
   }
   /* magic follows */
   e->band[0].begin=2;  e->band[0].end=4;
   e->band[1].begin=4;  e->band[1].end=5;
   e->band[2].begin=6;  e->band[2].end=6;
   e->band[3].begin=9;  e->band[3].end=8;
   e->band[4].begin=13;  e->band[4].end=8;
   e->band[5].begin=17;  e->band[5].end=8;
   e->band[6].begin=22;  e->band[6].end=8;
   for(j=0;j<VE_BANDS;j++){
     n=e->band[j].end;
     e->band[j].window=_ogg_malloc(n*sizeof(*e->band[0].window));
     for(i=0;i<n;i++){
       e->band[j].window[i]=sin((i+.5)/n*M_PI);
       e->band[j].total+=e->band[j].window[i];
     }
     e->band[j].total=1./e->band[j].total;
   }
   e->filter=_ogg_calloc(VE_BANDS*ch,sizeof(*e->filter));
   e->mark=_ogg_calloc(e->storage,sizeof(*e->mark));
 }
 void _ve_envelope_clear(envelope_lookup *e){
   int i;
   mdct_clear(&e->mdct);
   for(i=0;i<VE_BANDS;i++)
     _ogg_free(e->band[i].window);
   _ogg_free(e->mdct_win);
   _ogg_free(e->filter);
   _ogg_free(e->mark);
   memset(e,0,sizeof(*e));
 }
 /* fairly straight threshhold-by-band based until we find something
    that works better and isn't patented. */
 static int _ve_amp(envelope_lookup *ve,
                    vorbis_info_psy_global *gi,
                    float *data,
                    envelope_band *bands,
                    envelope_filter_state *filters){
   long n=ve->winlength;
   int ret=0;
   long i,j;
   float decay;
   /* we want to have a 'minimum bar' for energy, else we're just
      basing blocks on quantization noise that outweighs the signal
      itself (for low power signals) */
   float minV=ve->minenergy;
   float *vec=alloca(n*sizeof(*vec));
   /* stretch is used to gradually lengthen the number of windows
      considered prevoius-to-potential-trigger */
   int stretch=max(VE_MINSTRETCH,ve->stretch/2);
   float penalty=gi->stretch_penalty-(ve->stretch/2-VE_MINSTRETCH);
   if(penalty<0.f)penalty=0.f;
   if(penalty>gi->stretch_penalty)penalty=gi->stretch_penalty;
   /*_analysis_output_always("lpcm",seq2,data,n,0,0,
     totalshift+pos*ve->searchstep);*/
  /* window and transform */
   for(i=0;i<n;i++)
     vec[i]=data[i]*ve->mdct_win[i];
   mdct_forward(&ve->mdct,vec,vec);
   /*_analysis_output_always("mdct",seq2,vec,n/2,0,1,0); */
   /* near-DC spreading function; this has nothing to do with
      psychoacoustics, just sidelobe leakage and window size */
   {
     float temp=vec[0]*vec[0]+.7*vec[1]*vec[1]+.2*vec[2]*vec[2];
     int ptr=filters->nearptr;
     /* the accumulation is regularly refreshed from scratch to avoid
        floating point creep */
     if(ptr==0){
       decay=filters->nearDC_acc=filters->nearDC_partialacc+temp;
       filters->nearDC_partialacc=temp;
     }else{
       decay=filters->nearDC_acc+=temp;
       filters->nearDC_partialacc+=temp;
     }
     filters->nearDC_acc-=filters->nearDC[ptr];
     filters->nearDC[ptr]=temp;
     decay*=(1./(VE_NEARDC+1));
     filters->nearptr++;
     if(filters->nearptr>=VE_NEARDC)filters->nearptr=0;
     decay=todB(&decay)*.5-15.f;
   }
   /* perform spreading and limiting, also smooth the spectrum.  yes,
      the MDCT results in all real coefficients, but it still *behaves*
      like real/imaginary pairs */
   for(i=0;i<n/2;i+=2){
     float val=vec[i]*vec[i]+vec[i+1]*vec[i+1];
     val=todB(&val)*.5f;
     if(val<decay)val=decay;
     if(val<minV)val=minV;
     vec[i>>1]=val;
     decay-=8.;
   }
   /*_analysis_output_always("spread",seq2++,vec,n/4,0,0,0);*/
   /* perform preecho/postecho triggering by band */
   for(j=0;j<VE_BANDS;j++){
     float acc=0.;
     float valmax,valmin;
     /* accumulate amplitude */
     for(i=0;i<bands[j].end;i++)
       acc+=vec[i+bands[j].begin]*bands[j].window[i];
     acc*=bands[j].total;
     /* convert amplitude to delta */
     {
       int p,this=filters[j].ampptr;
       float postmax,postmin,premax=-99999.f,premin=99999.f;
       p=this;
       p--;
       if(p<0)p+=VE_AMP;
       postmax=max(acc,filters[j].ampbuf[p]);
       postmin=min(acc,filters[j].ampbuf[p]);
       for(i=0;i<stretch;i++){
         p--;
         if(p<0)p+=VE_AMP;
         premax=max(premax,filters[j].ampbuf[p]);
         premin=min(premin,filters[j].ampbuf[p]);
       }
       valmin=postmin-premin;
       valmax=postmax-premax;
       /*filters[j].markers[pos]=valmax;*/
       filters[j].ampbuf[this]=acc;
       filters[j].ampptr++;
       if(filters[j].ampptr>=VE_AMP)filters[j].ampptr=0;
     }
     /* look at min/max, decide trigger */
     if(valmax>gi->preecho_thresh[j]+penalty){
       ret|=1;
       ret|=4;
     }
     if(valmin<gi->postecho_thresh[j]-penalty)ret|=2;
   }
   return(ret);
 }
 #if 0
 static int seq=0;
 static ogg_int64_t totalshift=-1024;
 #endif
 long _ve_envelope_search(vorbis_dsp_state *v){
   vorbis_info *vi=v->vi;
   codec_setup_info *ci=vi->codec_setup;
   vorbis_info_psy_global *gi=&ci->psy_g_param;
   envelope_lookup *ve=((private_state *)(v->backend_state))->ve;
   long i,j;
   int first=ve->current/ve->searchstep;
   int last=v->pcm_current/ve->searchstep-VE_WIN;
   if(first<0)first=0;
   /* make sure we have enough storage to match the PCM */
   if(last+VE_WIN+VE_POST>ve->storage){
     ve->storage=last+VE_WIN+VE_POST; /* be sure */
     ve->mark=_ogg_realloc(ve->mark,ve->storage*sizeof(*ve->mark));
   }
   for(j=first;j<last;j++){
     int ret=0;
     ve->stretch++;
     if(ve->stretch>VE_MAXSTRETCH*2)
       ve->stretch=VE_MAXSTRETCH*2;
     for(i=0;i<ve->ch;i++){
       float *pcm=v->pcm[i]+ve->searchstep*(j);
       ret|=_ve_amp(ve,gi,pcm,ve->band,ve->filter+i*VE_BANDS);
     }
     ve->mark[j+VE_POST]=0;
     if(ret&1){
       ve->mark[j]=1;
       ve->mark[j+1]=1;
     }
     if(ret&2){
       ve->mark[j]=1;
       if(j>0)ve->mark[j-1]=1;
     }
     if(ret&4)ve->stretch=-1;
   }
   ve->current=last*ve->searchstep;
   {
     long centerW=v->centerW;
     long testW=
       centerW+
       ci->blocksizes[v->W]/4+
       ci->blocksizes[1]/2+
       ci->blocksizes[0]/4;
     j=ve->cursor;
     while(j<ve->current-(ve->searchstep)){/* account for postecho
                                              working back one window */
       if(j>=testW)return(1);
       ve->cursor=j;
       if(ve->mark[j/ve->searchstep]){
         if(j>centerW){
 #if 0
           if(j>ve->curmark){
             float *marker=alloca(v->pcm_current*sizeof(*marker));
             int l,m;
             memset(marker,0,sizeof(*marker)*v->pcm_current);
             fprintf(stderr,"mark! seq=%d, cursor:%fs time:%fs\n",
                     seq,
                     (totalshift+ve->cursor)/44100.,
                     (totalshift+j)/44100.);
             _analysis_output_always("pcmL",seq,v->pcm[0],v->pcm_current,0,0,totalshift);
             _analysis_output_always("pcmR",seq,v->pcm[1],v->pcm_current,0,0,totalshift);
             _analysis_output_always("markL",seq,v->pcm[0],j,0,0,totalshift);
             _analysis_output_always("markR",seq,v->pcm[1],j,0,0,totalshift);
             for(m=0;m<VE_BANDS;m++){
               char buf[80];
               sprintf(buf,"delL%d",m);
               for(l=0;l<last;l++)marker[l*ve->searchstep]=ve->filter[m].markers[l]*.1;
               _analysis_output_always(buf,seq,marker,v->pcm_current,0,0,totalshift);
             }
             for(m=0;m<VE_BANDS;m++){
               char buf[80];
               sprintf(buf,"delR%d",m);
               for(l=0;l<last;l++)marker[l*ve->searchstep]=ve->filter[m+VE_BANDS].markers[l]*.1;
               _analysis_output_always(buf,seq,marker,v->pcm_current,0,0,totalshift);
             }
             for(l=0;l<last;l++)marker[l*ve->searchstep]=ve->mark[l]*.4;
             _analysis_output_always("mark",seq,marker,v->pcm_current,0,0,totalshift);
             seq++;
           }
 #endif
           ve->curmark=j;
           if(j>=testW)return(1);
           return(0);
         }
       }
       j+=ve->searchstep;
     }
   }
   return(-1);
 }
 int _ve_envelope_mark(vorbis_dsp_state *v){
   envelope_lookup *ve=((private_state *)(v->backend_state))->ve;
   vorbis_info *vi=v->vi;
   codec_setup_info *ci=vi->codec_setup;
   long centerW=v->centerW;
   long beginW=centerW-ci->blocksizes[v->W]/4;
   long endW=centerW+ci->blocksizes[v->W]/4;
   if(v->W){
     beginW-=ci->blocksizes[v->lW]/4;
     endW+=ci->blocksizes[v->nW]/4;
   }else{
     beginW-=ci->blocksizes[0]/4;
     endW+=ci->blocksizes[0]/4;
   }
   if(ve->curmark>=beginW && ve->curmark<endW)return(1);
   {
     long first=beginW/ve->searchstep;
     long last=endW/ve->searchstep;
     long i;
     for(i=first;i<last;i++)
       if(ve->mark[i])return(1);
   }
   return(0);
 }
 void _ve_envelope_shift(envelope_lookup *e,long shift){
   int smallsize=e->current/e->searchstep+VE_POST; /* adjust for placing marks
                                                      ahead of ve->current */
   int smallshift=shift/e->searchstep;
   memmove(e->mark,e->mark+smallshift,(smallsize-smallshift)*sizeof(*e->mark));
 #if 0
   for(i=0;i<VE_BANDS*e->ch;i++)
     memmove(e->filter[i].markers,
             e->filter[i].markers+smallshift,
             (1024-smallshift)*sizeof(*(*e->filter).markers));
   totalshift+=shift;
 #endif
   e->current-=shift;
   if(e->curmark>=0)
     e->curmark-=shift;
   e->cursor-=shift;
 }

The Tor Browser / annotate

media/libvorbis/lib/vorbis_envelope.c@b8a032363ba2 (annotated)

media/libvorbis/lib/vorbis_envelope.c