vid_snr.c

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/************************************************************************
 *
 *  vid_snr.c, part of tmn (TMN encoder)
 *  Copyright (C) 1995, 1996  Telenor R&D, Norway
 *        Karl Olav Lillevold <Karl.Lillevold@nta.no>
 *  
 *  Contacts: 
 *  Karl Olav Lillevold               <Karl.Lillevold@nta.no>, or
 *  Robert Danielsen                  <Robert.Danielsen@nta.no>
 *
 *  Telenor Research and Development  http://www.nta.no/brukere/DVC/
 *  P.O.Box 83                        tel.:   +47 63 84 84 00
 *  N-2007 Kjeller, Norway            fax.:   +47 63 81 00 76
 *  
 ************************************************************************/

/*
 * Disclaimer of Warranty
 *
 * These software programs are available to the user without any
 * license fee or royalty on an "as is" basis.  Telenor Research and
 * Development disclaims any and all warranties, whether express,
 * implied, or statuary, including any implied warranties or
 * merchantability or of fitness for a particular purpose.  In no
 * event shall the copyright-holder be liable for any incidental,
 * punitive, or consequential damages of any kind whatsoever arising
 * from the use of these programs.
 *
 * This disclaimer of warranty extends to the user of these programs
 * and user's customers, employees, agents, transferees, successors,
 * and assigns.
 *
 * Telenor Research and Development does not represent or warrant that
 * the programs furnished hereunder are free of infringement of any
 * third-party patents.
 *
 * Commercial implementations of H.263, including shareware, are
 * subject to royalty fees to patent holders.  Many of these patents
 * are general enough such that they are unavoidable regardless of
 * implementation design.
 * */


#include"vid_sim.h"
#include"video_codec.h"

extern video_codec *VidSt;

#include<math.h>

/**********************************************************************
 *
 *      Name:        SNRcomp
 *      Description:        Compares two image files using SNR
 *                      No conversion to 422
 *      
 *      Input:        
 *      Returns:       
 *      Side effects:
 *
 *      Date: 930711    Author: Karl.Lillevold@nta.no
 *
 ***********************************************************************/



void ComputeSNR(PictImage *im1, PictImage *im2, Results *res, int write)
{
  FILE *out = NULL;
  int n;
  register int m;
  int quad, quad_Cr, quad_Cb, diff;
  PictImage *diff_image = NULL;
  /* Diff. image written to diff_filename */
  char *diff_filename=DEF_DIFFILENAME;

  if (write) {
    out = fopen(diff_filename,"ab");
    diff_image = (PictImage *)malloc(sizeof(PictImage));
    diff_image->lum = (unsigned char *)malloc(sizeof(char)*(VidSt->pels)*(VidSt->lines));
    diff_image->Cr =  (unsigned char *)malloc(sizeof(char)*(VidSt->pels)*(VidSt->lines)/4);
    diff_image->Cb =  (unsigned char *)malloc(sizeof(char)*(VidSt->pels)*(VidSt->lines)/4);    
  }

  quad = 0;
  quad_Cr = quad_Cb = 0;
  /* Luminance */
  quad = 0;
  for (n = 0; n < (VidSt->lines); n++)
    for (m = 0; m < (VidSt->pels); m++) {
      diff = *(im1->lum + m + n*(VidSt->pels)) - *(im2->lum + m + n*(VidSt->pels));
      if (write)
        *(diff_image->lum + m + n*(VidSt->pels)) = 10*diff + 128;
      quad += diff * diff;
    }

  res->SNR_l = (float)quad/(float)((VidSt->pels)*(VidSt->lines));
  if (res->SNR_l) {
    res->SNR_l = (float)(255*255) / res->SNR_l;
    res->SNR_l = 10 * (float)log10(res->SNR_l);
  }
  else res->SNR_l = (float)99.99;

  /* Chrominance */
  for (n = 0; n < (VidSt->lines)/2; n++)
    for (m = 0; m < (VidSt->pels)/2; m++) {
      quad_Cr += (*(im1->Cr+m + n*(VidSt->pels)/2) - *(im2->Cr + m + n*(VidSt->pels)/2)) *
        (*(im1->Cr+m + n*(VidSt->pels)/2) - *(im2->Cr + m + n*(VidSt->pels)/2));
      quad_Cb += (*(im1->Cb+m + n*(VidSt->pels)/2) - *(im2->Cb + m + n*(VidSt->pels)/2)) *
        (*(im1->Cb+m + n*(VidSt->pels)/2) - *(im2->Cb + m + n*(VidSt->pels)/2));
      if (write) {
        *(diff_image->Cr + m + n*(VidSt->pels)/2) = 
          (*(im1->Cr+m + n*(VidSt->pels)/2) - *(im2->Cr + m + n*(VidSt->pels)/2))*10+128;
        *(diff_image->Cb + m + n*(VidSt->pels)/2) = 
          (*(im1->Cb+m + n*(VidSt->pels)/2) - *(im2->Cb + m + n*(VidSt->pels)/2))*10+128;
      }
    }

  res->SNR_Cr = (float)quad_Cr/(float)((VidSt->pels)*(VidSt->lines)/4);
  if (res->SNR_Cr) {
    res->SNR_Cr = (float)(255*255) / res->SNR_Cr;
    res->SNR_Cr = 10 * (float)log10(res->SNR_Cr);
  }
  else res->SNR_Cr = (float)99.99;

  res->SNR_Cb = (float)quad_Cb/(float)((VidSt->pels)*(VidSt->lines)/4);
  if (res->SNR_Cb) {
    res->SNR_Cb = (float)(255*255) / res->SNR_Cb;
    res->SNR_Cb = 10 * (float)log10(res->SNR_Cb);
  }
  else res->SNR_Cb = (float)99.99;

  if (write) {
    fwrite(diff_image->lum, sizeof(char), (VidSt->pels)*(VidSt->lines), out);
    fwrite(diff_image->Cr,  sizeof(char), (VidSt->pels)*(VidSt->lines)/4, out);
    fwrite(diff_image->Cb,  sizeof(char), (VidSt->pels)*(VidSt->lines)/4, out);
    free(diff_image->lum);
    free(diff_image->Cr);
    free(diff_image->Cb);
    free(diff_image);
    fclose(out);
  }
  return;
}

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