LCOV - code coverage report
Current view: top level - libavcodec - dirac_arith.c (source / functions) Hit Total Coverage
Test: coverage.info Lines: 22 22 100.0 %
Date: 2017-12-17 16:07:53 Functions: 2 2 100.0 %

          Line data    Source code
       1             : /*
       2             :  * Copyright (C) 2007 Marco Gerards <marco@gnu.org>
       3             :  * Copyright (C) 2009 David Conrad
       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             :  * Arithmetic decoder for Dirac
      25             :  * @author Marco Gerards <marco@gnu.org>
      26             :  */
      27             : 
      28             : #include "dirac_arith.h"
      29             : 
      30             : 
      31             : const uint16_t ff_dirac_prob[256] = {
      32             :     0,    2,    5,    8,    11,   15,   20,   24,
      33             :     29,   35,   41,   47,   53,   60,   67,   74,
      34             :     82,   89,   97,   106,  114,  123,  132,  141,
      35             :     150,  160,  170,  180,  190,  201,  211,  222,
      36             :     233,  244,  256,  267,  279,  291,  303,  315,
      37             :     327,  340,  353,  366,  379,  392,  405,  419,
      38             :     433,  447,  461,  475,  489,  504,  518,  533,
      39             :     548,  563,  578,  593,  609,  624,  640,  656,
      40             :     672,  688,  705,  721,  738,  754,  771,  788,
      41             :     805,  822,  840,  857,  875,  892,  910,  928,
      42             :     946,  964,  983,  1001, 1020, 1038, 1057, 1076,
      43             :     1095, 1114, 1133, 1153, 1172, 1192, 1211, 1231,
      44             :     1251, 1271, 1291, 1311, 1332, 1352, 1373, 1393,
      45             :     1414, 1435, 1456, 1477, 1498, 1520, 1541, 1562,
      46             :     1584, 1606, 1628, 1649, 1671, 1694, 1716, 1738,
      47             :     1760, 1783, 1806, 1828, 1851, 1874, 1897, 1920,
      48             :     1935, 1942, 1949, 1955, 1961, 1968, 1974, 1980,
      49             :     1985, 1991, 1996, 2001, 2006, 2011, 2016, 2021,
      50             :     2025, 2029, 2033, 2037, 2040, 2044, 2047, 2050,
      51             :     2053, 2056, 2058, 2061, 2063, 2065, 2066, 2068,
      52             :     2069, 2070, 2071, 2072, 2072, 2072, 2072, 2072,
      53             :     2072, 2071, 2070, 2069, 2068, 2066, 2065, 2063,
      54             :     2060, 2058, 2055, 2052, 2049, 2045, 2042, 2038,
      55             :     2033, 2029, 2024, 2019, 2013, 2008, 2002, 1996,
      56             :     1989, 1982, 1975, 1968, 1960, 1952, 1943, 1934,
      57             :     1925, 1916, 1906, 1896, 1885, 1874, 1863, 1851,
      58             :     1839, 1827, 1814, 1800, 1786, 1772, 1757, 1742,
      59             :     1727, 1710, 1694, 1676, 1659, 1640, 1622, 1602,
      60             :     1582, 1561, 1540, 1518, 1495, 1471, 1447, 1422,
      61             :     1396, 1369, 1341, 1312, 1282, 1251, 1219, 1186,
      62             :     1151, 1114, 1077, 1037, 995,  952,  906,  857,
      63             :     805,  750,  690,  625,  553,  471,  376,  255
      64             : };
      65             : 
      66             : const uint8_t ff_dirac_next_ctx[DIRAC_CTX_COUNT] = {
      67             :     [CTX_ZPZN_F1]   = CTX_ZP_F2,
      68             :     [CTX_ZPNN_F1]   = CTX_ZP_F2,
      69             :     [CTX_ZP_F2]     = CTX_ZP_F3,
      70             :     [CTX_ZP_F3]     = CTX_ZP_F4,
      71             :     [CTX_ZP_F4]     = CTX_ZP_F5,
      72             :     [CTX_ZP_F5]     = CTX_ZP_F6,
      73             :     [CTX_ZP_F6]     = CTX_ZP_F6,
      74             :     [CTX_NPZN_F1]   = CTX_NP_F2,
      75             :     [CTX_NPNN_F1]   = CTX_NP_F2,
      76             :     [CTX_NP_F2]     = CTX_NP_F3,
      77             :     [CTX_NP_F3]     = CTX_NP_F4,
      78             :     [CTX_NP_F4]     = CTX_NP_F5,
      79             :     [CTX_NP_F5]     = CTX_NP_F6,
      80             :     [CTX_NP_F6]     = CTX_NP_F6,
      81             :     [CTX_DELTA_Q_F] = CTX_DELTA_Q_F,
      82             : };
      83             : 
      84             : int16_t ff_dirac_prob_branchless[256][2];
      85             : 
      86          29 : av_cold void ff_dirac_init_arith_tables(void)
      87             : {
      88             :     int i;
      89             : 
      90        7453 :     for (i = 0; i < 256; i++) {
      91        7424 :         ff_dirac_prob_branchless[i][0] =  ff_dirac_prob[255-i];
      92        7424 :         ff_dirac_prob_branchless[i][1] = -ff_dirac_prob[i];
      93             :     }
      94          29 : }
      95             : 
      96         926 : void ff_dirac_init_arith_decoder(DiracArith *c, GetBitContext *gb, int length)
      97             : {
      98             :     int i;
      99         926 :     align_get_bits(gb);
     100             : 
     101         926 :     length = FFMIN(length, get_bits_left(gb)/8);
     102             : 
     103         926 :     c->bytestream     = gb->buffer + get_bits_count(gb)/8;
     104         926 :     c->bytestream_end = c->bytestream + length;
     105         926 :     skip_bits_long(gb, length*8);
     106             : 
     107         926 :     c->low = 0;
     108        4630 :     for (i = 0; i < 4; i++) {
     109        3704 :         c->low <<= 8;
     110        3704 :         if (c->bytestream < c->bytestream_end)
     111        3694 :             c->low |= *c->bytestream++;
     112             :         else
     113          10 :             c->low |= 0xff;
     114             :     }
     115             : 
     116         926 :     c->counter = -16;
     117         926 :     c->range   = 0xffff;
     118             : 
     119       21298 :     for (i = 0; i < DIRAC_CTX_COUNT; i++)
     120       20372 :         c->contexts[i] = 0x8000;
     121         926 : }

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