ref: a7c01127f9749fe471367c6461cde357403cc3b3
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;
}