H.264/AVC Reference Software Encoder: img_dist

00001 
00002 /*!
00003  *************************************************************************************
00004  * \file img_dist_snr.c
00005  *
00006  * \brief
00007  *    Compute signal to noise ratio (SNR) between the encoded image and the reference image
00008  *
00009  * \author
00010  *    Main contributors (see contributors.h for copyright, address and affiliation details)
00011  *     - Woo-Shik Kim                    <wooshik.kim@usc.edu>
00012  *     - Alexis Michael Tourapis         <alexismt@ieee.org>
00013  *************************************************************************************
00014  */
00015 #include "contributors.h"
00016 
00017 #include <math.h>
00018 
00019 #include "global.h"
00020 #include "img_distortion.h"
00021 #include "enc_statistics.h"
00022 
00023 /*!
00024  ************************************************************************
00025  * \brief
00026  *    Find SNR for all three components
00027  ************************************************************************
00028  */
00029 void find_snr(ImageStructure *imgREF, ImageStructure *imgSRC, DistMetric *metricSSE, DistMetric *metricPSNR)
00030 {
00031   FrameFormat *format = &imgREF->format;
00032   // Luma.
00033   metricSSE ->value[0] = (float) compute_SSE(imgREF->data[0], imgSRC->data[0], 0, 0, format->height, format->width);
00034   metricPSNR->value[0] = psnr(format->max_value_sq[0], format->size_cmp[0], metricSSE->value[0]);
00035 
00036   // Chroma.
00037   if (format->yuv_format != YUV400)
00038   {   
00039     metricSSE ->value[1] = (float) compute_SSE(imgREF->data[1], imgSRC->data[1], 0, 0, format->height_cr, format->width_cr);
00040     metricPSNR->value[1] = psnr(format->max_value_sq[1], format->size_cmp[1], metricSSE->value[1]);
00041     metricSSE ->value[2] = (float) compute_SSE(imgREF->data[2], imgSRC->data[2], 0, 0, format->height_cr, format->width_cr);
00042     metricPSNR->value[2] = psnr(format->max_value_sq[2], format->size_cmp[2], metricSSE->value[2]);
00043   }
00044    
00045   {
00046     accumulate_average(metricSSE,  dist->frame_ctr);
00047     accumulate_average(metricPSNR, dist->frame_ctr);
00048 
00049     accumulate_avslice(metricSSE,  img->type, stats->frame_ctr[img->type]);
00050     accumulate_avslice(metricPSNR, img->type, stats->frame_ctr[img->type]);
00051   }
00052 }