LCOV - code coverage report
Current view: top level - libavcodec - dctref.c (source / functions) Hit Total Coverage
Test: coverage.info Lines: 34 34 100.0 %
Date: 2017-12-10 21:22:29 Functions: 3 3 100.0 %

          Line data    Source code
       1             : /*
       2             :  * reference discrete cosine transform (double precision)
       3             :  * Copyright (C) 2009 Dylan Yudaken
       4             :  *
       5             :  * This file is part of FFmpeg.
       6             :  *
       7             :  * FFmpeg is free software; you can redistribute it and/or
       8             :  * modify it under the terms of the GNU Lesser General Public
       9             :  * License as published by the Free Software Foundation; either
      10             :  * version 2.1 of the License, or (at your option) any later version.
      11             :  *
      12             :  * FFmpeg is distributed in the hope that it will be useful,
      13             :  * but WITHOUT ANY WARRANTY; without even the implied warranty of
      14             :  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      15             :  * Lesser General Public License for more details.
      16             :  *
      17             :  * You should have received a copy of the GNU Lesser General Public
      18             :  * License along with FFmpeg; if not, write to the Free Software
      19             :  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
      20             :  */
      21             : 
      22             : /**
      23             :  * @file
      24             :  * reference discrete cosine transform (double precision)
      25             :  *
      26             :  * @author Dylan Yudaken (dyudaken at gmail)
      27             :  *
      28             :  * @note This file could be optimized a lot, but is for
      29             :  * reference and so readability is better.
      30             :  */
      31             : 
      32             : #include "libavutil/mathematics.h"
      33             : #include "dctref.h"
      34             : 
      35             : static double coefficients[8 * 8];
      36             : 
      37             : /**
      38             :  * Initialize the double precision discrete cosine transform
      39             :  * functions fdct & idct.
      40             :  */
      41           5 : av_cold void ff_ref_dct_init(void)
      42             : {
      43             :     unsigned int i, j;
      44             : 
      45          45 :     for (j = 0; j < 8; ++j) {
      46          40 :         coefficients[j] = sqrt(0.125);
      47         320 :         for (i = 8; i < 64; i += 8) {
      48         280 :             coefficients[i + j] = 0.5 * cos(i * (j + 0.5) * M_PI / 64.0);
      49             :         }
      50             :     }
      51           5 : }
      52             : 
      53             : /**
      54             :  * Transform 8x8 block of data with a double precision forward DCT <br>
      55             :  * This is a reference implementation.
      56             :  *
      57             :  * @param block pointer to 8x8 block of data to transform
      58             :  */
      59      520000 : void ff_ref_fdct(short *block)
      60             : {
      61             :     /* implement the equation: block = coefficients * block * coefficients' */
      62             : 
      63             :     unsigned int i, j, k;
      64             :     double out[8 * 8];
      65             : 
      66             :     /* out = coefficients * block */
      67     4680000 :     for (i = 0; i < 64; i += 8) {
      68    37440000 :         for (j = 0; j < 8; ++j) {
      69    33280000 :             double tmp = 0;
      70   299520000 :             for (k = 0; k < 8; ++k) {
      71   266240000 :                 tmp += coefficients[i + k] * block[k * 8 + j];
      72             :             }
      73    33280000 :             out[i + j] = tmp * 8;
      74             :         }
      75             :     }
      76             : 
      77             :     /* block = out * (coefficients') */
      78     4680000 :     for (j = 0; j < 8; ++j) {
      79    37440000 :         for (i = 0; i < 64; i += 8) {
      80    33280000 :             double tmp = 0;
      81   299520000 :             for (k = 0; k < 8; ++k) {
      82   266240000 :                 tmp += out[i + k] * coefficients[j * 8 + k];
      83             :             }
      84    33280000 :             block[i + j] = floor(tmp + 0.499999999999);
      85             :         }
      86             :     }
      87      520000 : }
      88             : 
      89             : /**
      90             :  * Transform 8x8 block of data with a double precision inverse DCT <br>
      91             :  * This is a reference implementation.
      92             :  *
      93             :  * @param block pointer to 8x8 block of data to transform
      94             :  */
      95     1140000 : void ff_ref_idct(short *block)
      96             : {
      97             :     /* implement the equation: block = (coefficients') * block * coefficients */
      98             : 
      99             :     unsigned int i, j, k;
     100             :     double out[8 * 8];
     101             : 
     102             :     /* out = block * coefficients */
     103    10260000 :     for (i = 0; i < 64; i += 8) {
     104    82080000 :         for (j = 0; j < 8; ++j) {
     105    72960000 :             double tmp = 0;
     106   656640000 :             for (k = 0; k < 8; ++k) {
     107   583680000 :                 tmp += block[i + k] * coefficients[k * 8 + j];
     108             :             }
     109    72960000 :             out[i + j] = tmp;
     110             :         }
     111             :     }
     112             : 
     113             :     /* block = (coefficients') * out */
     114    10260000 :     for (i = 0; i < 8; ++i) {
     115    82080000 :         for (j = 0; j < 8; ++j) {
     116    72960000 :             double tmp = 0;
     117   656640000 :             for (k = 0; k < 64; k += 8) {
     118   583680000 :                 tmp += coefficients[k + i] * out[k + j];
     119             :             }
     120    72960000 :             block[i * 8 + j] = floor(tmp + 0.5);
     121             :         }
     122             :     }
     123     1140000 : }

Generated by: LCOV version 1.13