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1/*
2 * H.26L/H.264/AVC/JVT/14496-10/... encoder/decoder
3 * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
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 * Context Adaptive Binary Arithmetic Coder.
25 */
26
27#include <string.h>
28
29#include "libavutil/common.h"
30#include "libavutil/timer.h"
31
32#include "cabac.h"
33#include "cabac_functions.h"
34
35const uint8_t ff_h264_cabac_tables[512 + 4*2*64 + 4*64 + 63] = {
36 9,8,7,7,6,6,6,6,5,5,5,5,5,5,5,5,
37 4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,
38 3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,
39 3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,
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 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
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 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,
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,
55 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 // LPS range
57 -128, -128, -128, -128, -128, -128, 123, 123,
58 116, 116, 111, 111, 105, 105, 100, 100,
59 95, 95, 90, 90, 85, 85, 81, 81,
60 77, 77, 73, 73, 69, 69, 66, 66,
61 62, 62, 59, 59, 56, 56, 53, 53,
62 51, 51, 48, 48, 46, 46, 43, 43,
63 41, 41, 39, 39, 37, 37, 35, 35,
64 33, 33, 32, 32, 30, 30, 29, 29,
65 27, 27, 26, 26, 24, 24, 23, 23,
66 22, 22, 21, 21, 20, 20, 19, 19,
67 18, 18, 17, 17, 16, 16, 15, 15,
68 14, 14, 14, 14, 13, 13, 12, 12,
69 12, 12, 11, 11, 11, 11, 10, 10,
70 10, 10, 9, 9, 9, 9, 8, 8,
71 8, 8, 7, 7, 7, 7, 7, 7,
72 6, 6, 6, 6, 6, 6, 2, 2,
73 -80, -80, -89, -89, -98, -98, -106, -106,
74 -114, -114, -121, -121, -128, -128, 122, 122,
75 116, 116, 110, 110, 104, 104, 99, 99,
76 94, 94, 89, 89, 85, 85, 80, 80,
77 76, 76, 72, 72, 69, 69, 65, 65,
78 62, 62, 59, 59, 56, 56, 53, 53,
79 50, 50, 48, 48, 45, 45, 43, 43,
80 41, 41, 39, 39, 37, 37, 35, 35,
81 33, 33, 31, 31, 30, 30, 28, 28,
82 27, 27, 26, 26, 24, 24, 23, 23,
83 22, 22, 21, 21, 20, 20, 19, 19,
84 18, 18, 17, 17, 16, 16, 15, 15,
85 14, 14, 14, 14, 13, 13, 12, 12,
86 12, 12, 11, 11, 11, 11, 10, 10,
87 9, 9, 9, 9, 9, 9, 8, 8,
88 8, 8, 7, 7, 7, 7, 2, 2,
89 -48, -48, -59, -59, -69, -69, -78, -78,
90 -87, -87, -96, -96, -104, -104, -112, -112,
91 -119, -119, -126, -126, 123, 123, 117, 117,
92 111, 111, 105, 105, 100, 100, 95, 95,
93 90, 90, 86, 86, 81, 81, 77, 77,
94 73, 73, 69, 69, 66, 66, 63, 63,
95 59, 59, 56, 56, 54, 54, 51, 51,
96 48, 48, 46, 46, 43, 43, 41, 41,
97 39, 39, 37, 37, 35, 35, 33, 33,
98 32, 32, 30, 30, 29, 29, 27, 27,
99 26, 26, 25, 25, 23, 23, 22, 22,
100 21, 21, 20, 20, 19, 19, 18, 18,
101 17, 17, 16, 16, 15, 15, 15, 15,
102 14, 14, 13, 13, 12, 12, 12, 12,
103 11, 11, 11, 11, 10, 10, 10, 10,
104 9, 9, 9, 9, 8, 8, 2, 2,
105 -16, -16, -29, -29, -40, -40, -51, -51,
106 -61, -61, -71, -71, -81, -81, -90, -90,
107 -98, -98, -106, -106, -114, -114, -121, -121,
108 -128, -128, 122, 122, 116, 116, 110, 110,
109 104, 104, 99, 99, 94, 94, 89, 89,
110 85, 85, 80, 80, 76, 76, 72, 72,
111 69, 69, 65, 65, 62, 62, 59, 59,
112 56, 56, 53, 53, 50, 50, 48, 48,
113 45, 45, 43, 43, 41, 41, 39, 39,
114 37, 37, 35, 35, 33, 33, 31, 31,
115 30, 30, 28, 28, 27, 27, 25, 25,
116 24, 24, 23, 23, 22, 22, 21, 21,
117 20, 20, 19, 19, 18, 18, 17, 17,
118 16, 16, 15, 15, 14, 14, 14, 14,
119 13, 13, 12, 12, 12, 12, 11, 11,
120 11, 11, 10, 10, 9, 9, 2, 2,
121 // mlps state
122 127, 126, 77, 76, 77, 76, 75, 74,
123 75, 74, 75, 74, 73, 72, 73, 72,
124 73, 72, 71, 70, 71, 70, 71, 70,
125 69, 68, 69, 68, 67, 66, 67, 66,
126 67, 66, 65, 64, 65, 64, 63, 62,
127 61, 60, 61, 60, 61, 60, 59, 58,
128 59, 58, 57, 56, 55, 54, 55, 54,
129 53, 52, 53, 52, 51, 50, 49, 48,
130 49, 48, 47, 46, 45, 44, 45, 44,
131 43, 42, 43, 42, 39, 38, 39, 38,
132 37, 36, 37, 36, 33, 32, 33, 32,
133 31, 30, 31, 30, 27, 26, 27, 26,
134 25, 24, 23, 22, 23, 22, 19, 18,
135 19, 18, 17, 16, 15, 14, 13, 12,
136 11, 10, 9, 8, 9, 8, 5, 4,
137 5, 4, 3, 2, 1, 0, 0, 1,
138 2, 3, 4, 5, 6, 7, 8, 9,
139 10, 11, 12, 13, 14, 15, 16, 17,
140 18, 19, 20, 21, 22, 23, 24, 25,
141 26, 27, 28, 29, 30, 31, 32, 33,
142 34, 35, 36, 37, 38, 39, 40, 41,
143 42, 43, 44, 45, 46, 47, 48, 49,
144 50, 51, 52, 53, 54, 55, 56, 57,
145 58, 59, 60, 61, 62, 63, 64, 65,
146 66, 67, 68, 69, 70, 71, 72, 73,
147 74, 75, 76, 77, 78, 79, 80, 81,
148 82, 83, 84, 85, 86, 87, 88, 89,
149 90, 91, 92, 93, 94, 95, 96, 97,
150 98, 99, 100, 101, 102, 103, 104, 105,
151 106, 107, 108, 109, 110, 111, 112, 113,
152 114, 115, 116, 117, 118, 119, 120, 121,
153 122, 123, 124, 125, 124, 125, 126, 127,
154 // last_coeff_flag_offset_8x8
155 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
156 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
157 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4,
158 5, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8
159};
160
161/**
162 * @param buf_size size of buf in bits
163 */
164void ff_init_cabac_encoder(CABACContext *c, uint8_t *buf, int buf_size){
165 init_put_bits(&c->pb, buf, buf_size);
166
167 c->low= 0;
168 c->range= 0x1FE;
169 c->outstanding_count= 0;
170 c->pb.bit_left++; //avoids firstBitFlag
171}
172
173/**
174 *
175 * @param buf_size size of buf in bits
176 */
177int ff_init_cabac_decoder(CABACContext *c, const uint8_t *buf, int buf_size){
178 c->bytestream_start=
179 c->bytestream= buf;
180 c->bytestream_end= buf + buf_size;
181
182#if CABAC_BITS == 16
183 c->low = (*c->bytestream++)<<18;
184 c->low+= (*c->bytestream++)<<10;
185 // Keep our fetches on a 2-byte boundary as this should avoid ever having to
186 // do unaligned loads if the compiler (or asm) optimises the double byte
187 // load into a single instruction
188 if(((uintptr_t)c->bytestream & 1) == 0) {
189 c->low += (1 << 9);
190 }
191 else {
192 c->low += ((*c->bytestream++) << 2) + 2;
193 }
194#else
195 c->low = (*c->bytestream++)<<10;
196 c->low+= ((*c->bytestream++)<<2) + 2;
197#endif
198 c->range= 0x1FE;
199 if ((c->range<<(CABAC_BITS+1)) < c->low)
200 return AVERROR_INVALIDDATA;
201 return 0;
202}
203
generated by cgit at 2024-05-17 02:05:20 (GMT)