x264中的PSNR计算及其打印

2010-01-22 21:39

x264在设置参数后，如果不进行psnr的设置，在编译的时候是不会打印出来信噪比的信息的，这里，只要在参数里面进行设置一下，如：--psnr，就可以打印出YUV的峰值信噪比的信息来，这里就把，在程序中的信噪比的计算和相关函数在这里列举出来： 1.这里是先定义求解信噪比的函数： static float x264_psnr( int64_t i_sqe, int64_t i_size ) { double f_mse = (double)i_sqe / ((double)65025.0 * (double)i_size); if( f_mse <= 0.0000000001 ) /* Max 100dB */ return 100; return (float)(-10.0 * log( f_mse ) / log( 10.0 )); } 2.函数的调用： if( h->param.analyse.b_psnr ) { int64_t ssd[3] = { h->stat.frame.i_ssd[0], h->stat.frame.i_ssd[1], h->stat.frame.i_ssd[2], }; h->stat.i_ssd_global[h->sh.i_type] += ssd[0] + ssd[1] + ssd[2]; h->stat.f_psnr_average[h->sh.i_type] += x264_psnr( ssd[0] + ssd[1] + ssd[2], 3 * h->param.i_width * h->param.i_height / 2 ); h->stat.f_psnr_mean_y[h->sh.i_type] += x264_psnr( ssd[0], h->param.i_width * h->param.i_height ); h->stat.f_psnr_mean_u[h->sh.i_type] += x264_psnr( ssd[1], h->param.i_width * h->param.i_height / 4 ); h->stat.f_psnr_mean_v[h->sh.i_type] += x264_psnr( ssd[2], h->param.i_width * h->param.i_height / 4 ); snprintf( psz_message, 80, " PSNR Y:%5.2f U:%5.2f V:%5.2f", x264_psnr( ssd[0], h->param.i_width * h->param.i_height ), x264_psnr( ssd[1], h->param.i_width * h->param.i_height / 4), x264_psnr( ssd[2], h->param.i_width * h->param.i_height / 4) ); } ...................................................................................... if( h->param.analyse.b_psnr ) { x264_log( h, X264_LOG_INFO, "slice %s:%-5d Avg QP:%5.2f  size:%6.0f  PSNR Mean Y:%5.2f U:%5.2f V:%5.2f Avg:%5.2f Global:%5.2f\n", slice_name[i_slice], i_count, h->stat.f_slice_qp[i_slice] / i_count, (double)h->stat.i_slice_size[i_slice] / i_count, h->stat.f_psnr_mean_y[i_slice] / i_count, h->stat.f_psnr_mean_u[i_slice] / i_count, h->stat.f_psnr_mean_v[i_slice] / i_count, h->stat.f_psnr_average[i_slice] / i_count, x264_psnr( h->stat.i_ssd_global[i_slice], i_count * i_yuv_size ) ); } .......................................................... if( h->param.analyse.b_psnr ) { x264_log( h, X264_LOG_INFO, "PSNR Mean Y:%6.3f U:%6.3f V:%6.3f Avg:%6.3f Global:%6.3f kb/s:%.2f\n", SUM3( h->stat.f_psnr_mean_y ) / i_count, SUM3( h->stat.f_psnr_mean_u ) / i_count, SUM3( h->stat.f_psnr_mean_v ) / i_count, SUM3( h->stat.f_psnr_average ) / i_count, x264_psnr( SUM3( h->stat.i_ssd_global ), i_count * i_yuv_size ), f_bitrate ); } else x264_log( h, X264_LOG_INFO, "kb/s:%.1f\n", f_bitrate ); 这里还有一部分变量的定义，基本完成了这些内容！