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