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|---|---|---|---|
| 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 | static const uint16_t 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 | 35 | av_cold void ff_dirac_init_arith_tables(void) | |
| 87 | { | ||
| 88 | int i; | ||
| 89 | |||
| 90 |
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8995 | for (i = 0; i < 256; i++) { |
| 91 | 8960 | ff_dirac_prob_branchless[i][0] = dirac_prob[255-i]; | |
| 92 | 8960 | ff_dirac_prob_branchless[i][1] = -dirac_prob[i]; | |
| 93 | } | ||
| 94 | 35 | } | |
| 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 |
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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 |
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4630 | for (i = 0; i < 4; i++) { |
| 109 | 3704 | c->low <<= 8; | |
| 110 |
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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 | 926 | c->error = 0; | |
| 119 | 926 | c->overread= 0; | |
| 120 | |||
| 121 |
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21298 | for (i = 0; i < DIRAC_CTX_COUNT; i++) |
| 122 | 20372 | c->contexts[i] = 0x8000; | |
| 123 | 926 | } | |
| 124 |