diff options
Diffstat (limited to 'libavcodec/dirac_arith.c')
| -rw-r--r-- | libavcodec/dirac_arith.c | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/libavcodec/dirac_arith.c b/libavcodec/dirac_arith.c new file mode 100644 index 0000000000..bf913928b3 --- /dev/null +++ b/libavcodec/dirac_arith.c @@ -0,0 +1,116 @@ +/* + * Copyright (C) 2007 Marco Gerards <marco@gnu.org> + * Copyright (C) 2009 David Conrad + * + * This file is part of FFmpeg. + * + * FFmpeg is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * FFmpeg is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with FFmpeg; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +/** + * @file + * Arithmetic decoder for Dirac + * @author Marco Gerards <marco@gnu.org> + */ + +#include "dirac_arith.h" + + +const uint16_t ff_dirac_prob[256] = { + 0, 2, 5, 8, 11, 15, 20, 24, + 29, 35, 41, 47, 53, 60, 67, 74, + 82, 89, 97, 106, 114, 123, 132, 141, + 150, 160, 170, 180, 190, 201, 211, 222, + 233, 244, 256, 267, 279, 291, 303, 315, + 327, 340, 353, 366, 379, 392, 405, 419, + 433, 447, 461, 475, 489, 504, 518, 533, + 548, 563, 578, 593, 609, 624, 640, 656, + 672, 688, 705, 721, 738, 754, 771, 788, + 805, 822, 840, 857, 875, 892, 910, 928, + 946, 964, 983, 1001, 1020, 1038, 1057, 1076, + 1095, 1114, 1133, 1153, 1172, 1192, 1211, 1231, + 1251, 1271, 1291, 1311, 1332, 1352, 1373, 1393, + 1414, 1435, 1456, 1477, 1498, 1520, 1541, 1562, + 1584, 1606, 1628, 1649, 1671, 1694, 1716, 1738, + 1760, 1783, 1806, 1828, 1851, 1874, 1897, 1920, + 1935, 1942, 1949, 1955, 1961, 1968, 1974, 1980, + 1985, 1991, 1996, 2001, 2006, 2011, 2016, 2021, + 2025, 2029, 2033, 2037, 2040, 2044, 2047, 2050, + 2053, 2056, 2058, 2061, 2063, 2065, 2066, 2068, + 2069, 2070, 2071, 2072, 2072, 2072, 2072, 2072, + 2072, 2071, 2070, 2069, 2068, 2066, 2065, 2063, + 2060, 2058, 2055, 2052, 2049, 2045, 2042, 2038, + 2033, 2029, 2024, 2019, 2013, 2008, 2002, 1996, + 1989, 1982, 1975, 1968, 1960, 1952, 1943, 1934, + 1925, 1916, 1906, 1896, 1885, 1874, 1863, 1851, + 1839, 1827, 1814, 1800, 1786, 1772, 1757, 1742, + 1727, 1710, 1694, 1676, 1659, 1640, 1622, 1602, + 1582, 1561, 1540, 1518, 1495, 1471, 1447, 1422, + 1396, 1369, 1341, 1312, 1282, 1251, 1219, 1186, + 1151, 1114, 1077, 1037, 995, 952, 906, 857, + 805, 750, 690, 625, 553, 471, 376, 255 +}; + +const uint8_t ff_dirac_next_ctx[DIRAC_CTX_COUNT] = { + [CTX_ZPZN_F1] = CTX_ZP_F2, + [CTX_ZPNN_F1] = CTX_ZP_F2, + [CTX_ZP_F2] = CTX_ZP_F3, + [CTX_ZP_F3] = CTX_ZP_F4, + [CTX_ZP_F4] = CTX_ZP_F5, + [CTX_ZP_F5] = CTX_ZP_F6, + [CTX_ZP_F6] = CTX_ZP_F6, + [CTX_NPZN_F1] = CTX_NP_F2, + [CTX_NPNN_F1] = CTX_NP_F2, + [CTX_NP_F2] = CTX_NP_F3, + [CTX_NP_F3] = CTX_NP_F4, + [CTX_NP_F4] = CTX_NP_F5, + [CTX_NP_F5] = CTX_NP_F6, + [CTX_NP_F6] = CTX_NP_F6, + [CTX_DELTA_Q_F] = CTX_DELTA_Q_F, +}; + +int16_t ff_dirac_prob_branchless[256][2]; + +void ff_dirac_init_arith_decoder(DiracArith *c, GetBitContext *gb, int length) +{ + int i; + align_get_bits(gb); + + length = FFMIN(length, get_bits_left(gb)/8); + + c->bytestream = gb->buffer + get_bits_count(gb)/8; + c->bytestream_end = c->bytestream + length; + skip_bits_long(gb, length*8); + + c->low = 0; + for (i = 0; i < 4; i++) { + c->low <<= 8; + if (c->bytestream < c->bytestream_end) + c->low |= *c->bytestream++; + else + c->low |= 0xff; + } + + c->counter = -16; + c->range = 0xffff; + + for (i = 0; i < 256; i++) { + ff_dirac_prob_branchless[i][0] = ff_dirac_prob[255-i]; + ff_dirac_prob_branchless[i][1] = -ff_dirac_prob[i]; + } + + for (i = 0; i < DIRAC_CTX_COUNT; i++) + c->contexts[i] = 0x8000; +} |