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/********************************************************************
* *
* THIS FILE IS PART OF THE Ogg Vorbis SOFTWARE CODEC SOURCE CODE. *
* USE, DISTRIBUTION AND REPRODUCTION OF THIS SOURCE IS GOVERNED BY *
* THE GNU PUBLIC LICENSE 2, WHICH IS INCLUDED WITH THIS SOURCE. *
* PLEASE READ THESE TERMS DISTRIBUTING. *
* *
* THE OggSQUISH SOURCE CODE IS (C) COPYRIGHT 1994-2000 *
* by Monty <monty@xiph.org> and The XIPHOPHORUS Company *
* http://www.xiph.org/ *
* *
********************************************************************
function: PCM data envelope analysis and manipulation
last mod: $Id: envelope.c,v 1.19 2000/06/18 12:33:47 xiphmont Exp $
Preecho calculation.
********************************************************************/
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <math.h>
#include "vorbis/codec.h"
#include "os.h"
#include "scales.h"
#include "smallft.h"
#include "envelope.h"
#include "bitwise.h"
#include "window.h"
#include "misc.h"
void _ve_envelope_init(envelope_lookup *e,int samples_per){
int i;
e->winlen=samples_per*2;
e->window=malloc(e->winlen*sizeof(double));
e->fft=calloc(1,sizeof(drft_lookup));
drft_init(e->fft,samples_per*2);
/* We just use a straight sin(x) window for this */
for(i=0;i<e->winlen;i++)
e->window[i]=sin((i+.5)/e->winlen*M_PI);
}
void _ve_envelope_clear(envelope_lookup *e){
drft_clear(e->fft);
free(e->fft);
if(e->window)free(e->window);
memset(e,0,sizeof(envelope_lookup));
}
static void smooth_noise(long n,double *f,double *noise){
long i;
long lo=0,hi=0;
double acc=0.;
for(i=0;i<n;i++){
/* not exactly correct, (the center frequency should be centered
on a *log* scale), but not worth quibbling */
long newhi=i*1.0442718740+5;
long newlo=i*.8781245150-5;
if(newhi>n)newhi=n;
for(;lo<newlo;lo++)
acc-=todB(f[lo]); /* yeah, this ain't RMS */
for(;hi<newhi;hi++)
acc+=todB(f[hi]);
noise[i]=acc/(hi-lo);
}
}
/* use FFT for spectral power estimation */
static int frameno=0;
static int frameno2=0;
static void _ve_deltas(double *deltas,double *pcm,int n,double *window,
int samples_per,drft_lookup *l){
int i,j;
double *out=alloca(sizeof(double)*samples_per*2);
double *cache=alloca(sizeof(double)*samples_per*2);
for(j=-1;j<n;j++){
memcpy(out,pcm+(j+1)*samples_per,samples_per*2*sizeof(double));
for(i=0;i<samples_per*2;i++)
out[i]*=window[i];
_analysis_output("Dpcm",frameno*1000+frameno2,out,samples_per*2,0,0);
drft_forward(l,out);
for(i=1;i<samples_per;i++)
out[i]=hypot(out[i*2],out[i*2-1]);
_analysis_output("Dfft",frameno*1000+frameno2,out,samples_per,0,1);
smooth_noise(samples_per,out,out+samples_per);
if(j==-1){
for(i=samples_per/10;i<samples_per;i++)
cache[i]=out[i+samples_per];
}else{
double max=0;
_analysis_output("Dcache",frameno*1000+frameno2,cache,samples_per,0,0);
for(i=samples_per/10;i<samples_per;i++){
double val=out[i+samples_per]-cache[i];
cache[i]=out[i+samples_per];
if(val>0)max+=val;
}
max/=samples_per;
if(deltas[j]<max)deltas[j]=max;
}
_analysis_output("Dnoise",frameno*1000+frameno2++,out+samples_per,samples_per,0,0);
}
}
void _ve_envelope_deltas(vorbis_dsp_state *v){
vorbis_info *vi=v->vi;
int step=vi->envelopesa;
int dtotal=v->pcm_current/vi->envelopesa-1;
int dcurr=v->envelope_current;
int pch;
if(dtotal>dcurr){
double *mult=v->multipliers+dcurr;
memset(mult,0,sizeof(double)*(dtotal-dcurr));
for(pch=0;pch<vi->channels;pch++){
double *pcm=v->pcm[pch]+(dcurr-1)*step;
_ve_deltas(mult,pcm,dtotal-dcurr,v->ve.window,step,v->ve.fft);
{
double *multexp=alloca(sizeof(double)*v->pcm_current);
int i,j,k;
memset(multexp,0,sizeof(double)*v->pcm_current);
j=0;
for(i=0;i<dtotal;i++)
for(k=0;k<step;k++)
multexp[j++]=v->multipliers[i];
_analysis_output("Apcm",frameno,v->pcm[pch],v->pcm_current,0,0);
_analysis_output("Amult",frameno++,multexp,v->pcm_current,0,0);
}
}
v->envelope_current=dtotal;
}
}
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