ref: 2fe3b28f86ed4aa291fb8a620b948abe9c6a1f84
dir: /sys/src/cmd/audio/libvorbis/envelope.c/
/******************************************************************** * * * 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=malloc(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; } free(vec); 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; }