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;
186 // Keep our fetches on a 2-byte boundry as this should avoid ever having to
187 // do unaligned loads if the compiler (or asm) optimises the double byte
188 // load into a single instruction
189 if(((uintptr_t)c->bytestream & 1) == 0) {
193 c->low += ((*c->bytestream++) << 2) + 2;
196 c->low = (*c->bytestream++)<<10;
197 c->low+= ((*c->bytestream++)<<2) + 2;
200 if ((c->range<<(CABAC_BITS+1)) < c->low)
201 return AVERROR_INVALIDDATA;
208 #include "libavutil/lfg.h"
211 static inline void put_cabac_bit(CABACContext *c, int b){
212 put_bits(&c->pb, 1, b);
213 for(;c->outstanding_count; c->outstanding_count--){
214 put_bits(&c->pb, 1, 1-b);
218 static inline void renorm_cabac_encoder(CABACContext *c){
219 while(c->range < 0x100){
223 }else if(c->low<0x200){
224 c->outstanding_count++;
236 static void put_cabac(CABACContext *c, uint8_t * const state, int bit){
237 int RangeLPS= ff_h264_lps_range[2*(c->range&0xC0) + *state];
239 if(bit == ((*state)&1)){
240 c->range -= RangeLPS;
241 *state = ff_h264_mlps_state[128 + *state];
243 c->low += c->range - RangeLPS;
245 *state= ff_h264_mlps_state[127 - *state];
248 renorm_cabac_encoder(c);
252 * @param bit 0 -> write zero bit, !=0 write one bit
254 static void put_cabac_bypass(CABACContext *c, int bit){
263 }else if(c->low<0x400){
264 c->outstanding_count++;
274 * @return the number of bytes written
276 static int put_cabac_terminate(CABACContext *c, int bit){
280 renorm_cabac_encoder(c);
285 renorm_cabac_encoder(c);
287 av_assert0(c->low <= 0x1FF);
288 put_cabac_bit(c, c->low>>9);
289 put_bits(&c->pb, 2, ((c->low>>7)&3)|1);
291 flush_put_bits(&c->pb); //FIXME FIXME FIXME XXX wrong
294 return (put_bits_count(&c->pb)+7)>>3;
302 uint8_t state[10]= {0};
305 av_lfg_init(&prng, 1);
306 ff_init_cabac_encoder(&c, b, SIZE);
308 for(i=0; i<SIZE; i++){
309 if(2*i<SIZE) r[i] = av_lfg_get(&prng) % 7;
310 else r[i] = (i>>8)&1;
313 for(i=0; i<SIZE; i++){
314 put_cabac_bypass(&c, r[i]&1);
317 for(i=0; i<SIZE; i++){
318 put_cabac(&c, state, r[i]&1);
321 i= put_cabac_terminate(&c, 1);
322 b[i++] = av_lfg_get(&prng);
323 b[i ] = av_lfg_get(&prng);
325 ff_init_cabac_decoder(&c, b, SIZE);
327 memset(state, 0, sizeof(state));
329 for(i=0; i<SIZE; i++){
330 if( (r[i]&1) != get_cabac_bypass(&c) ) {
331 av_log(NULL, AV_LOG_ERROR, "CABAC bypass failure at %d\n", i);
336 for(i=0; i<SIZE; i++){
337 if( (r[i]&1) != get_cabac_noinline(&c, state) ) {
338 av_log(NULL, AV_LOG_ERROR, "CABAC failure at %d\n", i);
342 if(!get_cabac_terminate(&c)) {
343 av_log(NULL, AV_LOG_ERROR, "where's the Terminator?\n");