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 FFmpeg.
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.
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.
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
24 * Context Adaptive Binary Arithmetic Coder.
29 #include "libavutil/common.h"
30 #include "libavutil/timer.h"
33 #include "cabac_functions.h"
35 const 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,
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,
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
163 * @param buf_size size of buf in bits
165 void ff_init_cabac_encoder(CABACContext *c, uint8_t *buf, int buf_size){
166 init_put_bits(&c->pb, buf, buf_size);
170 c->outstanding_count= 0;
171 c->pb.bit_left++; //avoids firstBitFlag
176 * @param buf_size size of buf in bits
178 int ff_init_cabac_decoder(CABACContext *c, const uint8_t *buf, int buf_size){
181 c->bytestream_end= buf + buf_size;
184 c->low = (*c->bytestream++)<<18;
185 c->low+= (*c->bytestream++)<<10;
187 c->low = (*c->bytestream++)<<10;
189 c->low+= ((*c->bytestream++)<<2) + 2;
191 if ((c->range<<(CABAC_BITS+1)) < c->low)
192 return AVERROR_INVALIDDATA;
199 #include "libavutil/lfg.h"
202 static inline void put_cabac_bit(CABACContext *c, int b){
203 put_bits(&c->pb, 1, b);
204 for(;c->outstanding_count; c->outstanding_count--){
205 put_bits(&c->pb, 1, 1-b);
209 static inline void renorm_cabac_encoder(CABACContext *c){
210 while(c->range < 0x100){
214 }else if(c->low<0x200){
215 c->outstanding_count++;
227 static void put_cabac(CABACContext *c, uint8_t * const state, int bit){
228 int RangeLPS= ff_h264_lps_range[2*(c->range&0xC0) + *state];
230 if(bit == ((*state)&1)){
231 c->range -= RangeLPS;
232 *state = ff_h264_mlps_state[128 + *state];
234 c->low += c->range - RangeLPS;
236 *state= ff_h264_mlps_state[127 - *state];
239 renorm_cabac_encoder(c);
243 * @param bit 0 -> write zero bit, !=0 write one bit
245 static void put_cabac_bypass(CABACContext *c, int bit){
254 }else if(c->low<0x400){
255 c->outstanding_count++;
265 * @return the number of bytes written
267 static int put_cabac_terminate(CABACContext *c, int bit){
271 renorm_cabac_encoder(c);
276 renorm_cabac_encoder(c);
278 av_assert0(c->low <= 0x1FF);
279 put_cabac_bit(c, c->low>>9);
280 put_bits(&c->pb, 2, ((c->low>>7)&3)|1);
282 flush_put_bits(&c->pb); //FIXME FIXME FIXME XXX wrong
285 return (put_bits_count(&c->pb)+7)>>3;
293 uint8_t state[10]= {0};
296 av_lfg_init(&prng, 1);
297 ff_init_cabac_encoder(&c, b, SIZE);
299 for(i=0; i<SIZE; i++){
300 if(2*i<SIZE) r[i] = av_lfg_get(&prng) % 7;
301 else r[i] = (i>>8)&1;
304 for(i=0; i<SIZE; i++){
305 put_cabac_bypass(&c, r[i]&1);
308 for(i=0; i<SIZE; i++){
309 put_cabac(&c, state, r[i]&1);
312 put_cabac_terminate(&c, 1);
314 ff_init_cabac_decoder(&c, b, SIZE);
316 memset(state, 0, sizeof(state));
318 for(i=0; i<SIZE; i++){
319 if( (r[i]&1) != get_cabac_bypass(&c) ) {
320 av_log(NULL, AV_LOG_ERROR, "CABAC bypass failure at %d\n", i);
325 for(i=0; i<SIZE; i++){
326 if( (r[i]&1) != get_cabac_noinline(&c, state) ) {
327 av_log(NULL, AV_LOG_ERROR, "CABAC failure at %d\n", i);
331 if(!get_cabac_terminate(&c)) {
332 av_log(NULL, AV_LOG_ERROR, "where's the Terminator?\n");