mpeg2enc/stats.c

   1 /* stats.c, coding statistics                                               */
   2
   3 /* Copyright (C) 1996, MPEG Software Simulation Group. All Rights Reserved. */
   4
   5 /*
   6  * Disclaimer of Warranty
   7  *
   8  * These software programs are available to the user without any license fee or
   9  * royalty on an "as is" basis.  The MPEG Software Simulation Group disclaims
  10  * any and all warranties, whether express, implied, or statuary, including any
  11  * implied warranties or merchantability or of fitness for a particular
  12  * purpose.  In no event shall the copyright-holder be liable for any
  13  * incidental, punitive, or consequential damages of any kind whatsoever
  14  * arising from the use of these programs.
  15  *
  16  * This disclaimer of warranty extends to the user of these programs and user's
  17  * customers, employees, agents, transferees, successors, and assigns.
  18  *
  19  * The MPEG Software Simulation Group does not represent or warrant that the
  20  * programs furnished hereunder are free of infringement of any third-party
  21  * patents.
  22  *
  23  * Commercial implementations of MPEG-1 and MPEG-2 video, including shareware,
  24  * are subject to royalty fees to patent holders.  Many of these patents are
  25  * general enough such that they are unavoidable regardless of implementation
  26  * design.
  27  *
  28  */
  29
  30 #include <stdio.h>
  31 #include <math.h>
  32 #include "config.h"
  33 #include "global.h"
  34
  35 /* private prototypes */
  36 static void calcSNR1 _ANSI_ARGS_((unsigned char *org, unsigned char *rec,
  37   int lx, int w, int h, double *pv, double *pe));
  38
  39
  40 void calcSNR(org,rec)
  41 unsigned char *org[3];
  42 unsigned char *rec[3];
  43 {
  44 }
  45
  46 static void calcSNR1(org,rec,lx,w,h,pv,pe)
  47 unsigned char *org;
  48 unsigned char *rec;
  49 int lx,w,h;
  50 double *pv,*pe;
  51 {
  52   int i, j;
  53   double v1, s1, s2, e2;
  54
  55   s1 = s2 = e2 = 0.0;
  56
  57   for (j=0; j<h; j++)
  58   {
  59     for (i=0; i<w; i++)
  60     {
  61       v1 = org[i];
  62       s1+= v1;
  63       s2+= v1*v1;
  64       v1-= rec[i];
  65       e2+= v1*v1;
  66     }
  67     org += lx;
  68     rec += lx;
  69   }
  70
  71   s1 /= w*h;
  72   s2 /= w*h;
  73   e2 /= w*h;
  74
  75   /* prevent division by zero in calcSNR() */
  76   if(e2==0.0)
  77     e2 = 0.00001;
  78
  79   *pv = s2 - s1*s1; /* variance */
  80   *pe = e2;         /* MSE */
  81 }
  82
  83 void stats()
  84 {
  85 }