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
|
/*
* 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 inline functions
*/
#ifndef AVCODEC_CABAC_FUNCTIONS_H
#define AVCODEC_CABAC_FUNCTIONS_H
#include <stdint.h>
#include "cabac.h"
#include "config.h"
#ifndef UNCHECKED_BITSTREAM_READER
#define UNCHECKED_BITSTREAM_READER !CONFIG_SAFE_BITSTREAM_READER
#endif
#if ARCH_AARCH64
# include "aarch64/cabac.h"
#endif
#if ARCH_ARM
# include "arm/cabac.h"
#endif
#if ARCH_X86
# include "x86/cabac.h"
#endif
#if ARCH_MIPS
# include "mips/cabac.h"
#endif
static const uint8_t * const ff_h264_norm_shift = ff_h264_cabac_tables + H264_NORM_SHIFT_OFFSET;
static const uint8_t * const ff_h264_lps_range = ff_h264_cabac_tables + H264_LPS_RANGE_OFFSET;
static const uint8_t * const ff_h264_mlps_state = ff_h264_cabac_tables + H264_MLPS_STATE_OFFSET;
static const uint8_t * const ff_h264_last_coeff_flag_offset_8x8 = ff_h264_cabac_tables + H264_LAST_COEFF_FLAG_OFFSET_8x8_OFFSET;
#if !defined(get_cabac_bypass) || !defined(get_cabac_terminate)
static void refill(CABACContext *c){
#if CABAC_BITS == 16
c->low+= (c->bytestream[0]<<9) + (c->bytestream[1]<<1);
#else
c->low+= c->bytestream[0]<<1;
#endif
c->low -= CABAC_MASK;
#if !UNCHECKED_BITSTREAM_READER
if (c->bytestream < c->bytestream_end)
#endif
c->bytestream += CABAC_BITS / 8;
}
#endif
#ifndef get_cabac_terminate
static inline void renorm_cabac_decoder_once(CABACContext *c){
int shift= (uint32_t)(c->range - 0x100)>>31;
c->range<<= shift;
c->low <<= shift;
if(!(c->low & CABAC_MASK))
refill(c);
}
#endif
#ifndef get_cabac_inline
static void refill2(CABACContext *c){
int i;
unsigned x;
#if !HAVE_FAST_CLZ
x= c->low ^ (c->low-1);
i= 7 - ff_h264_norm_shift[x>>(CABAC_BITS-1)];
#else
i = ff_ctz(c->low) - CABAC_BITS;
#endif
x= -CABAC_MASK;
#if CABAC_BITS == 16
x+= (c->bytestream[0]<<9) + (c->bytestream[1]<<1);
#else
x+= c->bytestream[0]<<1;
#endif
c->low += x<<i;
#if !UNCHECKED_BITSTREAM_READER
if (c->bytestream < c->bytestream_end)
#endif
c->bytestream += CABAC_BITS/8;
}
#endif
#ifndef get_cabac_inline
static av_always_inline int get_cabac_inline(CABACContext *c, uint8_t * const state){
int s = *state;
int RangeLPS= ff_h264_lps_range[2*(c->range&0xC0) + s];
int bit, lps_mask;
c->range -= RangeLPS;
lps_mask= ((c->range<<(CABAC_BITS+1)) - c->low)>>31;
c->low -= (c->range<<(CABAC_BITS+1)) & lps_mask;
c->range += (RangeLPS - c->range) & lps_mask;
s^=lps_mask;
*state= (ff_h264_mlps_state+128)[s];
bit= s&1;
lps_mask= ff_h264_norm_shift[c->range];
c->range<<= lps_mask;
c->low <<= lps_mask;
if(!(c->low & CABAC_MASK))
refill2(c);
return bit;
}
#endif
static int av_noinline av_unused get_cabac_noinline(CABACContext *c, uint8_t * const state){
return get_cabac_inline(c,state);
}
static int av_unused get_cabac(CABACContext *c, uint8_t * const state){
return get_cabac_inline(c,state);
}
#ifndef get_cabac_bypass
static int av_unused get_cabac_bypass(CABACContext *c){
int range;
c->low += c->low;
if(!(c->low & CABAC_MASK))
refill(c);
range= c->range<<(CABAC_BITS+1);
if(c->low < range){
return 0;
}else{
c->low -= range;
return 1;
}
}
#endif
#ifndef get_cabac_bypass_sign
static av_always_inline int get_cabac_bypass_sign(CABACContext *c, int val){
int range, mask;
c->low += c->low;
if(!(c->low & CABAC_MASK))
refill(c);
range= c->range<<(CABAC_BITS+1);
c->low -= range;
mask= c->low >> 31;
range &= mask;
c->low += range;
return (val^mask)-mask;
}
#endif
/**
* @return the number of bytes read or 0 if no end
*/
#ifndef get_cabac_terminate
static int av_unused get_cabac_terminate(CABACContext *c){
c->range -= 2;
if(c->low < c->range<<(CABAC_BITS+1)){
renorm_cabac_decoder_once(c);
return 0;
}else{
return c->bytestream - c->bytestream_start;
}
}
#endif
/**
* Skip @p n bytes and reset the decoder.
* @return the address of the first skipped byte or NULL if there's less than @p n bytes left
*/
#ifndef skip_bytes
static av_unused const uint8_t* skip_bytes(CABACContext *c, int n) {
const uint8_t *ptr = c->bytestream;
if (c->low & 0x1)
ptr--;
#if CABAC_BITS == 16
if (c->low & 0x1FF)
ptr--;
#endif
if ((int) (c->bytestream_end - ptr) < n)
return NULL;
if (ff_init_cabac_decoder(c, ptr + n, c->bytestream_end - ptr - n) < 0)
return NULL;
return ptr;
}
#endif
#endif /* AVCODEC_CABAC_FUNCTIONS_H */
|
