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/********************************************************************
* *
* 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 1994-2001 *
* by the Xiph.Org Foundation http://www.xiph.org/ *
* *
********************************************************************
function: metrics and quantization code for LSP VQ codebooks
last mod: $Id: lspdata.c,v 1.4 2008-02-02 15:54:08 richardash1981 Exp $
********************************************************************/
#include <stdlib.h>
#include <math.h>
#include <stdio.h>
#include "vqgen.h"
#include "vqext.h"
#include "codebook.h"
char *vqext_booktype="LSPdata";
quant_meta q={0,0,0,1}; /* set sequence data */
int vqext_aux=1;
float global_maxdel=M_PI;
float global_mindel=M_PI;
#if 0
void vqext_quantize(vqgen *v,quant_meta *q){
float delta,mindel;
float maxquant=((1<<q->quant)-1);
int j,k;
/* first find the basic delta amount from the maximum span to be
encoded. Loosen the delta slightly to allow for additional error
during sequence quantization */
delta=(global_maxdel-global_mindel)/((1<<q->quant)-1.5f);
q->min=_float32_pack(global_mindel);
q->delta=_float32_pack(delta);
mindel=_float32_unpack(q->min);
delta=_float32_unpack(q->delta);
for(j=0;j<v->entries;j++){
float last=0;
for(k=0;k<v->elements;k++){
float val=_now(v,j)[k];
float now=rint((val-last-mindel)/delta);
_now(v,j)[k]=now;
if(now<0){
/* be paranoid; this should be impossible */
fprintf(stderr,"fault; quantized value<0\n");
exit(1);
}
if(now>maxquant){
/* be paranoid; this should be impossible */
fprintf(stderr,"fault; quantized value>max\n");
exit(1);
}
last=(now*delta)+mindel+last;
}
}
}
#else
void vqext_quantize(vqgen *v,quant_meta *q){
vqgen_quantize(v,q);
}
#endif
float *weight=NULL;
#if 0
/* LSP training metric. We weight error proportional to distance
*between* LSP vector values. The idea of this metric is not to set
final cells, but get the midpoint spacing into a form conducive to
what we want, which is weighting toward preserving narrower
features. */
#define FUDGE (global_maxdel-weight[i])
float *vqext_weight(vqgen *v,float *p){
int i;
int el=v->elements;
float lastp=0.f;
for(i=0;i<el;i++){
float predist=(p[i]-lastp);
float postdist=(p[i+1]-p[i]);
weight[i]=(predist<postdist?predist:postdist);
lastp=p[i];
}
return p;
}
#else
#define FUDGE 1.f
float *vqext_weight(vqgen *v,float *p){
return p;
}
#endif
/* candidate,actual */
float vqext_metric(vqgen *v,float *e, float *p){
int i;
int el=v->elements;
float acc=0.f;
for(i=0;i<el;i++){
float val=(p[i]-e[i])*FUDGE;
acc+=val*val;
}
return sqrt(acc/v->elements);
}
/* Data files are line-vectors, now just deltas. The codebook entries
want to be monotonically increasing, so we adjust */
/* assume vqext_aux==1 */
void vqext_addpoint_adj(vqgen *v,float *b,int start,int dim,int cols,int num){
float *a=alloca(sizeof(float)*(dim+1)); /* +aux */
float base=0;
int i;
for(i=0;i<dim;i++)
base=a[i]=b[i+start]+base;
if(start+dim+1>cols) /* +aux */
a[i]=M_PI;
else
a[i]=b[i+start]+base;
vqgen_addpoint(v,a,a+dim);
}
/* we just need to calc the global_maxdel from the training set */
void vqext_preprocess(vqgen *v){
long j,k;
global_maxdel=0.f;
global_mindel=M_PI;
for(j=0;j<v->points;j++){
float last=0.;
for(k=0;k<v->elements+v->aux;k++){
float p=_point(v,j)[k];
if(p-last>global_maxdel)global_maxdel=p-last;
if(p-last<global_mindel)global_mindel=p-last;
last=p;
}
}
weight=_ogg_malloc(sizeof(float)*v->elements);
}
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