1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
|
/*
* H.26L/H.264/AVC/JVT/14496-10/... encoder/decoder
* Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
*
* 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
* Context Adaptive Binary Arithmetic Coder.
*/
#include <string.h>
#include "libavutil/common.h"
#include "libavutil/timer.h"
#include "get_bits.h"
#include "cabac.h"
#include "cabac_functions.h"
#include "cabac_tablegen.h"
/**
*
* @param buf_size size of buf in bits
*/
void ff_init_cabac_encoder(CABACContext *c, uint8_t *buf, int buf_size){
init_put_bits(&c->pb, buf, buf_size);
c->low= 0;
c->range= 0x1FE;
c->outstanding_count= 0;
c->pb.bit_left++; //avoids firstBitFlag
}
/**
*
* @param buf_size size of buf in bits
*/
void ff_init_cabac_decoder(CABACContext *c, const uint8_t *buf, int buf_size){
c->bytestream_start=
c->bytestream= buf;
c->bytestream_end= buf + buf_size;
#if CABAC_BITS == 16
c->low = (*c->bytestream++)<<18;
c->low+= (*c->bytestream++)<<10;
#else
c->low = (*c->bytestream++)<<10;
#endif
c->low+= ((*c->bytestream++)<<2) + 2;
c->range= 0x1FE;
}
void ff_init_cabac_states(void)
{
static int initialized = 0;
if (initialized)
return;
cabac_tableinit();
initialized = 1;
}
#ifdef TEST
#define SIZE 10240
#include "libavutil/lfg.h"
#include "avcodec.h"
static inline void put_cabac_bit(CABACContext *c, int b){
put_bits(&c->pb, 1, b);
for(;c->outstanding_count; c->outstanding_count--){
put_bits(&c->pb, 1, 1-b);
}
}
static inline void renorm_cabac_encoder(CABACContext *c){
while(c->range < 0x100){
//FIXME optimize
if(c->low<0x100){
put_cabac_bit(c, 0);
}else if(c->low<0x200){
c->outstanding_count++;
c->low -= 0x100;
}else{
put_cabac_bit(c, 1);
c->low -= 0x200;
}
c->range+= c->range;
c->low += c->low;
}
}
static void put_cabac(CABACContext *c, uint8_t * const state, int bit){
int RangeLPS= ff_h264_lps_range[2*(c->range&0xC0) + *state];
if(bit == ((*state)&1)){
c->range -= RangeLPS;
*state = ff_h264_mlps_state[128 + *state];
}else{
c->low += c->range - RangeLPS;
c->range = RangeLPS;
*state= ff_h264_mlps_state[127 - *state];
}
renorm_cabac_encoder(c);
}
/**
* @param bit 0 -> write zero bit, !=0 write one bit
*/
static void put_cabac_bypass(CABACContext *c, int bit){
c->low += c->low;
if(bit){
c->low += c->range;
}
//FIXME optimize
if(c->low<0x200){
put_cabac_bit(c, 0);
}else if(c->low<0x400){
c->outstanding_count++;
c->low -= 0x200;
}else{
put_cabac_bit(c, 1);
c->low -= 0x400;
}
}
/**
*
* @return the number of bytes written
*/
static int put_cabac_terminate(CABACContext *c, int bit){
c->range -= 2;
if(!bit){
renorm_cabac_encoder(c);
}else{
c->low += c->range;
c->range= 2;
renorm_cabac_encoder(c);
av_assert0(c->low <= 0x1FF);
put_cabac_bit(c, c->low>>9);
put_bits(&c->pb, 2, ((c->low>>7)&3)|1);
flush_put_bits(&c->pb); //FIXME FIXME FIXME XXX wrong
}
return (put_bits_count(&c->pb)+7)>>3;
}
int main(void){
CABACContext c;
uint8_t b[9*SIZE];
uint8_t r[9*SIZE];
int i, ret = 0;
uint8_t state[10]= {0};
AVLFG prng;
av_lfg_init(&prng, 1);
ff_init_cabac_encoder(&c, b, SIZE);
ff_init_cabac_states();
for(i=0; i<SIZE; i++){
if(2*i<SIZE) r[i] = av_lfg_get(&prng) % 7;
else r[i] = (i>>8)&1;
}
for(i=0; i<SIZE; i++){
put_cabac_bypass(&c, r[i]&1);
}
for(i=0; i<SIZE; i++){
put_cabac(&c, state, r[i]&1);
}
put_cabac_terminate(&c, 1);
ff_init_cabac_decoder(&c, b, SIZE);
memset(state, 0, sizeof(state));
for(i=0; i<SIZE; i++){
if( (r[i]&1) != get_cabac_bypass(&c) ) {
av_log(NULL, AV_LOG_ERROR, "CABAC bypass failure at %d\n", i);
ret = 1;
}
}
for(i=0; i<SIZE; i++){
if( (r[i]&1) != get_cabac_noinline(&c, state) ) {
av_log(NULL, AV_LOG_ERROR, "CABAC failure at %d\n", i);
ret = 1;
}
}
if(!get_cabac_terminate(&c)) {
av_log(NULL, AV_LOG_ERROR, "where's the Terminator?\n");
ret = 1;
}
return ret;
}
#endif /* TEST */
|
