release/src/router/libvorbis/vq/lspdata.c

   1 /********************************************************************
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   7  *                                                                  *
   8  * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2001             *
   9  * by the Xiph.Org Foundation http://www.xiph.org/                  *
  10  *                                                                  *
  11  ********************************************************************
  12
  13  function: metrics and quantization code for LSP VQ codebooks
  14  last mod: $Id: lspdata.c 16037 2009-05-26 21:10:58Z xiphmont $
  15
  16  ********************************************************************/
  17
  18 #include <stdlib.h>
  19 #include <math.h>
  20 #include <stdio.h>
  21 #include "vqgen.h"
  22 #include "vqext.h"
  23 #include "codebook.h"
  24
  25 char *vqext_booktype="LSPdata";
  26 quant_meta q={0,0,0,1};          /* set sequence data */
  27 int vqext_aux=1;
  28
  29 float global_maxdel=M_PI;
  30 float global_mindel=M_PI;
  31 #if 0
  32 void vqext_quantize(vqgen *v,quant_meta *q){
  33   float delta,mindel;
  34   float maxquant=((1<<q->quant)-1);
  35   int j,k;
  36
  37   /* first find the basic delta amount from the maximum span to be
  38      encoded.  Loosen the delta slightly to allow for additional error
  39      during sequence quantization */
  40
  41   delta=(global_maxdel-global_mindel)/((1<<q->quant)-1.5f);
  42
  43   q->min=_float32_pack(global_mindel);
  44   q->delta=_float32_pack(delta);
  45
  46   mindel=_float32_unpack(q->min);
  47   delta=_float32_unpack(q->delta);
  48
  49   for(j=0;j<v->entries;j++){
  50     float last=0;
  51     for(k=0;k<v->elements;k++){
  52       float val=_now(v,j)[k];
  53       float now=rint((val-last-mindel)/delta);
  54
  55       _now(v,j)[k]=now;
  56       if(now<0){
  57         /* be paranoid; this should be impossible */
  58         fprintf(stderr,"fault; quantized value<0\n");
  59         exit(1);
  60       }
  61
  62       if(now>maxquant){
  63         /* be paranoid; this should be impossible */
  64         fprintf(stderr,"fault; quantized value>max\n");
  65         exit(1);
  66       }
  67       last=(now*delta)+mindel+last;
  68     }
  69   }
  70
  71 }
  72 #else
  73 void vqext_quantize(vqgen *v,quant_meta *q){
  74   vqgen_quantize(v,q);
  75 }
  76 #endif
  77
  78 float *weight=NULL;
  79 #if 0
  80 /* LSP training metric.  We weight error proportional to distance
  81    *between* LSP vector values.  The idea of this metric is not to set
  82    final cells, but get the midpoint spacing into a form conducive to
  83    what we want, which is weighting toward preserving narrower
  84    features. */
  85
  86 #define FUDGE (global_maxdel-weight[i])
  87
  88 float *vqext_weight(vqgen *v,float *p){
  89   int i;
  90   int el=v->elements;
  91   float lastp=0.f;
  92   for(i=0;i<el;i++){
  93     float predist=(p[i]-lastp);
  94     float postdist=(p[i+1]-p[i]);
  95     weight[i]=(predist<postdist?predist:postdist);
  96     lastp=p[i];
  97   }
  98   return p;
  99 }
 100 #else
 101 #define FUDGE 1.f
 102 float *vqext_weight(vqgen *v,float *p){
 103   return p;
 104 }
 105 #endif
 106
 107                             /* candidate,actual */
 108 float vqext_metric(vqgen *v,float *e, float *p){
 109   int i;
 110   int el=v->elements;
 111   float acc=0.f;
 112   for(i=0;i<el;i++){
 113     float val=(p[i]-e[i])*FUDGE;
 114     acc+=val*val;
 115   }
 116   return sqrt(acc/v->elements);
 117 }
 118
 119 /* Data files are line-vectors, now just deltas.  The codebook entries
 120    want to be monotonically increasing, so we adjust */
 121
 122 /* assume vqext_aux==1 */
 123 void vqext_addpoint_adj(vqgen *v,float *b,int start,int dim,int cols,int num){
 124   float *a=alloca(sizeof(float)*(dim+1)); /* +aux */
 125   float base=0;
 126   int i;
 127
 128   for(i=0;i<dim;i++)
 129     base=a[i]=b[i+start]+base;
 130
 131   if(start+dim+1>cols) /* +aux */
 132     a[i]=M_PI;
 133   else
 134     a[i]=b[i+start]+base;
 135
 136   vqgen_addpoint(v,a,a+dim);
 137 }
 138
 139 /* we just need to calc the global_maxdel from the training set */
 140 void vqext_preprocess(vqgen *v){
 141   long j,k;
 142
 143   global_maxdel=0.f;
 144   global_mindel=M_PI;
 145   for(j=0;j<v->points;j++){
 146     float last=0.;
 147     for(k=0;k<v->elements+v->aux;k++){
 148       float p=_point(v,j)[k];
 149       if(p-last>global_maxdel)global_maxdel=p-last;
 150       if(p-last<global_mindel)global_mindel=p-last;
 151       last=p;
 152     }
 153   }
 154
 155   weight=_ogg_malloc(sizeof(float)*v->elements);
 156 }
 157