2 * H.26L/H.264/AVC/JVT/14496-10/... encoder/decoder
3 * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
5 * This file is part of Libav.
7 * Libav 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.
12 * Libav 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.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24 * Context Adaptive Binary Arithmetic Coder.
29 #include "libavutil/common.h"
32 #include "cabac_functions.h"
34 const uint8_t ff_h264_cabac_tables[512 + 4*2*64 + 4*64 + 63] = {
35 9,8,7,7,6,6,6,6,5,5,5,5,5,5,5,5,
36 4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,
37 3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,
38 3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,
39 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
40 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
41 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
42 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
43 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
44 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
45 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
46 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
47 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
48 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
49 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
50 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
51 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
52 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
53 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
54 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
56 -128, -128, -128, -128, -128, -128, 123, 123,
57 116, 116, 111, 111, 105, 105, 100, 100,
58 95, 95, 90, 90, 85, 85, 81, 81,
59 77, 77, 73, 73, 69, 69, 66, 66,
60 62, 62, 59, 59, 56, 56, 53, 53,
61 51, 51, 48, 48, 46, 46, 43, 43,
62 41, 41, 39, 39, 37, 37, 35, 35,
63 33, 33, 32, 32, 30, 30, 29, 29,
64 27, 27, 26, 26, 24, 24, 23, 23,
65 22, 22, 21, 21, 20, 20, 19, 19,
66 18, 18, 17, 17, 16, 16, 15, 15,
67 14, 14, 14, 14, 13, 13, 12, 12,
68 12, 12, 11, 11, 11, 11, 10, 10,
69 10, 10, 9, 9, 9, 9, 8, 8,
70 8, 8, 7, 7, 7, 7, 7, 7,
71 6, 6, 6, 6, 6, 6, 2, 2,
72 -80, -80, -89, -89, -98, -98, -106, -106,
73 -114, -114, -121, -121, -128, -128, 122, 122,
74 116, 116, 110, 110, 104, 104, 99, 99,
75 94, 94, 89, 89, 85, 85, 80, 80,
76 76, 76, 72, 72, 69, 69, 65, 65,
77 62, 62, 59, 59, 56, 56, 53, 53,
78 50, 50, 48, 48, 45, 45, 43, 43,
79 41, 41, 39, 39, 37, 37, 35, 35,
80 33, 33, 31, 31, 30, 30, 28, 28,
81 27, 27, 26, 26, 24, 24, 23, 23,
82 22, 22, 21, 21, 20, 20, 19, 19,
83 18, 18, 17, 17, 16, 16, 15, 15,
84 14, 14, 14, 14, 13, 13, 12, 12,
85 12, 12, 11, 11, 11, 11, 10, 10,
86 9, 9, 9, 9, 9, 9, 8, 8,
87 8, 8, 7, 7, 7, 7, 2, 2,
88 -48, -48, -59, -59, -69, -69, -78, -78,
89 -87, -87, -96, -96, -104, -104, -112, -112,
90 -119, -119, -126, -126, 123, 123, 117, 117,
91 111, 111, 105, 105, 100, 100, 95, 95,
92 90, 90, 86, 86, 81, 81, 77, 77,
93 73, 73, 69, 69, 66, 66, 63, 63,
94 59, 59, 56, 56, 54, 54, 51, 51,
95 48, 48, 46, 46, 43, 43, 41, 41,
96 39, 39, 37, 37, 35, 35, 33, 33,
97 32, 32, 30, 30, 29, 29, 27, 27,
98 26, 26, 25, 25, 23, 23, 22, 22,
99 21, 21, 20, 20, 19, 19, 18, 18,
100 17, 17, 16, 16, 15, 15, 15, 15,
101 14, 14, 13, 13, 12, 12, 12, 12,
102 11, 11, 11, 11, 10, 10, 10, 10,
103 9, 9, 9, 9, 8, 8, 2, 2,
104 -16, -16, -29, -29, -40, -40, -51, -51,
105 -61, -61, -71, -71, -81, -81, -90, -90,
106 -98, -98, -106, -106, -114, -114, -121, -121,
107 -128, -128, 122, 122, 116, 116, 110, 110,
108 104, 104, 99, 99, 94, 94, 89, 89,
109 85, 85, 80, 80, 76, 76, 72, 72,
110 69, 69, 65, 65, 62, 62, 59, 59,
111 56, 56, 53, 53, 50, 50, 48, 48,
112 45, 45, 43, 43, 41, 41, 39, 39,
113 37, 37, 35, 35, 33, 33, 31, 31,
114 30, 30, 28, 28, 27, 27, 25, 25,
115 24, 24, 23, 23, 22, 22, 21, 21,
116 20, 20, 19, 19, 18, 18, 17, 17,
117 16, 16, 15, 15, 14, 14, 14, 14,
118 13, 13, 12, 12, 12, 12, 11, 11,
119 11, 11, 10, 10, 9, 9, 2, 2,
121 127, 126, 77, 76, 77, 76, 75, 74,
122 75, 74, 75, 74, 73, 72, 73, 72,
123 73, 72, 71, 70, 71, 70, 71, 70,
124 69, 68, 69, 68, 67, 66, 67, 66,
125 67, 66, 65, 64, 65, 64, 63, 62,
126 61, 60, 61, 60, 61, 60, 59, 58,
127 59, 58, 57, 56, 55, 54, 55, 54,
128 53, 52, 53, 52, 51, 50, 49, 48,
129 49, 48, 47, 46, 45, 44, 45, 44,
130 43, 42, 43, 42, 39, 38, 39, 38,
131 37, 36, 37, 36, 33, 32, 33, 32,
132 31, 30, 31, 30, 27, 26, 27, 26,
133 25, 24, 23, 22, 23, 22, 19, 18,
134 19, 18, 17, 16, 15, 14, 13, 12,
135 11, 10, 9, 8, 9, 8, 5, 4,
136 5, 4, 3, 2, 1, 0, 0, 1,
137 2, 3, 4, 5, 6, 7, 8, 9,
138 10, 11, 12, 13, 14, 15, 16, 17,
139 18, 19, 20, 21, 22, 23, 24, 25,
140 26, 27, 28, 29, 30, 31, 32, 33,
141 34, 35, 36, 37, 38, 39, 40, 41,
142 42, 43, 44, 45, 46, 47, 48, 49,
143 50, 51, 52, 53, 54, 55, 56, 57,
144 58, 59, 60, 61, 62, 63, 64, 65,
145 66, 67, 68, 69, 70, 71, 72, 73,
146 74, 75, 76, 77, 78, 79, 80, 81,
147 82, 83, 84, 85, 86, 87, 88, 89,
148 90, 91, 92, 93, 94, 95, 96, 97,
149 98, 99, 100, 101, 102, 103, 104, 105,
150 106, 107, 108, 109, 110, 111, 112, 113,
151 114, 115, 116, 117, 118, 119, 120, 121,
152 122, 123, 124, 125, 124, 125, 126, 127,
153 // last_coeff_flag_offset_8x8
154 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
155 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
156 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4,
157 5, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8
161 * @param buf_size size of buf in bits
163 void ff_init_cabac_decoder(CABACContext *c, const uint8_t *buf, int buf_size){
166 c->bytestream_end= buf + buf_size;
169 c->low = (*c->bytestream++)<<18;
170 c->low+= (*c->bytestream++)<<10;
172 c->low = (*c->bytestream++)<<10;
174 c->low+= ((*c->bytestream++)<<2) + 2;