vp8/encoder/psnr.c

   1 /*
   2  *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
   3  *
   4  *  Use of this source code is governed by a BSD-style license
   5  *  that can be found in the LICENSE file in the root of the source
   6  *  tree. An additional intellectual property rights grant can be found
   7  *  in the file PATENTS.  All contributing project authors may
   8  *  be found in the AUTHORS file in the root of the source tree.
   9  */
  10
  11
  12 #include "vpx_scale/yv12config.h"
  13 #include "math.h"
  14 #include "vp8/common/systemdependent.h" /* for vp8_clear_system_state() */
  15
  16 #define MAX_PSNR 60
  17
  18 double vp8_mse2psnr(double Samples, double Peak, double Mse)
  19 {
  20     double psnr;
  21
  22     if ((double)Mse > 0.0)
  23         psnr = 10.0 * log10(Peak * Peak * Samples / Mse);
  24     else
  25         psnr = MAX_PSNR;      // Limit to prevent / 0
  26
  27     if (psnr > MAX_PSNR)
  28         psnr = MAX_PSNR;
  29
  30     return psnr;
  31 }