|
0
|
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 inline functions
|
|
|
25 */
|
|
|
26
|
|
|
27 #ifndef AVCODEC_CABAC_FUNCTIONS_H
|
|
|
28 #define AVCODEC_CABAC_FUNCTIONS_H
|
|
|
29
|
|
|
30 #include <stdint.h>
|
|
|
31
|
|
|
32 #include "cabac.h"
|
|
|
33 #include "config.h"
|
|
|
34
|
|
|
35 #ifndef UNCHECKED_BITSTREAM_READER
|
|
|
36 #define UNCHECKED_BITSTREAM_READER !CONFIG_SAFE_BITSTREAM_READER
|
|
|
37 #endif
|
|
|
38
|
|
|
39 #if ARCH_AARCH64
|
|
|
40 # include "aarch64/cabac.h"
|
|
|
41 #endif
|
|
|
42 #if ARCH_ARM
|
|
|
43 # include "arm/cabac.h"
|
|
|
44 #endif
|
|
|
45 #if ARCH_X86
|
|
|
46 # include "x86/cabac.h"
|
|
|
47 #endif
|
|
|
48
|
|
|
49 static CABAC_TABLE_CONST uint8_t * const ff_h264_norm_shift = ff_h264_cabac_tables + H264_NORM_SHIFT_OFFSET;
|
|
|
50 static CABAC_TABLE_CONST uint8_t * const ff_h264_lps_range = ff_h264_cabac_tables + H264_LPS_RANGE_OFFSET;
|
|
|
51 static CABAC_TABLE_CONST uint8_t * const ff_h264_mlps_state = ff_h264_cabac_tables + H264_MLPS_STATE_OFFSET;
|
|
|
52 static CABAC_TABLE_CONST uint8_t * const ff_h264_last_coeff_flag_offset_8x8 = ff_h264_cabac_tables + H264_LAST_COEFF_FLAG_OFFSET_8x8_OFFSET;
|
|
|
53
|
|
|
54 static void refill(CABACContext *c){
|
|
|
55 #if CABAC_BITS == 16
|
|
|
56 c->low+= (c->bytestream[0]<<9) + (c->bytestream[1]<<1);
|
|
|
57 #else
|
|
|
58 c->low+= c->bytestream[0]<<1;
|
|
|
59 #endif
|
|
|
60 c->low -= CABAC_MASK;
|
|
|
61 #if !UNCHECKED_BITSTREAM_READER
|
|
|
62 if (c->bytestream < c->bytestream_end)
|
|
|
63 #endif
|
|
|
64 c->bytestream += CABAC_BITS / 8;
|
|
|
65 }
|
|
|
66
|
|
|
67 static inline void renorm_cabac_decoder_once(CABACContext *c){
|
|
|
68 int shift= (uint32_t)(c->range - 0x100)>>31;
|
|
|
69 c->range<<= shift;
|
|
|
70 c->low <<= shift;
|
|
|
71 if(!(c->low & CABAC_MASK))
|
|
|
72 refill(c);
|
|
|
73 }
|
|
|
74
|
|
|
75 #ifndef get_cabac_inline
|
|
|
76 static void refill2(CABACContext *c){
|
|
|
77 int i, x;
|
|
|
78
|
|
|
79 x= c->low ^ (c->low-1);
|
|
|
80 i= 7 - ff_h264_norm_shift[x>>(CABAC_BITS-1)];
|
|
|
81
|
|
|
82 x= -CABAC_MASK;
|
|
|
83
|
|
|
84 #if CABAC_BITS == 16
|
|
|
85 x+= (c->bytestream[0]<<9) + (c->bytestream[1]<<1);
|
|
|
86 #else
|
|
|
87 x+= c->bytestream[0]<<1;
|
|
|
88 #endif
|
|
|
89
|
|
|
90 c->low += x<<i;
|
|
|
91 #if !UNCHECKED_BITSTREAM_READER
|
|
|
92 if (c->bytestream < c->bytestream_end)
|
|
|
93 #endif
|
|
|
94 c->bytestream += CABAC_BITS/8;
|
|
|
95 }
|
|
|
96
|
|
|
97 static av_always_inline int get_cabac_inline(CABACContext *c, uint8_t * const state){
|
|
|
98 int s = *state;
|
|
|
99 int RangeLPS= ff_h264_lps_range[2*(c->range&0xC0) + s];
|
|
|
100 int bit, lps_mask;
|
|
|
101
|
|
|
102 c->range -= RangeLPS;
|
|
|
103 lps_mask= ((c->range<<(CABAC_BITS+1)) - c->low)>>31;
|
|
|
104
|
|
|
105 c->low -= (c->range<<(CABAC_BITS+1)) & lps_mask;
|
|
|
106 c->range += (RangeLPS - c->range) & lps_mask;
|
|
|
107
|
|
|
108 s^=lps_mask;
|
|
|
109 *state= (ff_h264_mlps_state+128)[s];
|
|
|
110 bit= s&1;
|
|
|
111
|
|
|
112 lps_mask= ff_h264_norm_shift[c->range];
|
|
|
113 c->range<<= lps_mask;
|
|
|
114 c->low <<= lps_mask;
|
|
|
115 if(!(c->low & CABAC_MASK))
|
|
|
116 refill2(c);
|
|
|
117 return bit;
|
|
|
118 }
|
|
|
119 #endif
|
|
|
120
|
|
|
121 static int av_noinline av_unused get_cabac_noinline(CABACContext *c, uint8_t * const state){
|
|
|
122 return get_cabac_inline(c,state);
|
|
|
123 }
|
|
|
124
|
|
|
125 static int av_unused get_cabac(CABACContext *c, uint8_t * const state){
|
|
|
126 return get_cabac_inline(c,state);
|
|
|
127 }
|
|
|
128
|
|
|
129 #ifndef get_cabac_bypass
|
|
|
130 static int av_unused get_cabac_bypass(CABACContext *c){
|
|
|
131 int range;
|
|
|
132 c->low += c->low;
|
|
|
133
|
|
|
134 if(!(c->low & CABAC_MASK))
|
|
|
135 refill(c);
|
|
|
136
|
|
|
137 range= c->range<<(CABAC_BITS+1);
|
|
|
138 if(c->low < range){
|
|
|
139 return 0;
|
|
|
140 }else{
|
|
|
141 c->low -= range;
|
|
|
142 return 1;
|
|
|
143 }
|
|
|
144 }
|
|
|
145 #endif
|
|
|
146
|
|
|
147 #ifndef get_cabac_bypass_sign
|
|
|
148 static av_always_inline int get_cabac_bypass_sign(CABACContext *c, int val){
|
|
|
149 int range, mask;
|
|
|
150 c->low += c->low;
|
|
|
151
|
|
|
152 if(!(c->low & CABAC_MASK))
|
|
|
153 refill(c);
|
|
|
154
|
|
|
155 range= c->range<<(CABAC_BITS+1);
|
|
|
156 c->low -= range;
|
|
|
157 mask= c->low >> 31;
|
|
|
158 range &= mask;
|
|
|
159 c->low += range;
|
|
|
160 return (val^mask)-mask;
|
|
|
161 }
|
|
|
162 #endif
|
|
|
163
|
|
|
164 /**
|
|
|
165 *
|
|
|
166 * @return the number of bytes read or 0 if no end
|
|
|
167 */
|
|
|
168 static int av_unused get_cabac_terminate(CABACContext *c){
|
|
|
169 c->range -= 2;
|
|
|
170 if(c->low < c->range<<(CABAC_BITS+1)){
|
|
|
171 renorm_cabac_decoder_once(c);
|
|
|
172 return 0;
|
|
|
173 }else{
|
|
|
174 return c->bytestream - c->bytestream_start;
|
|
|
175 }
|
|
|
176 }
|
|
|
177
|
|
|
178 /**
|
|
|
179 * Skip @p n bytes and reset the decoder.
|
|
|
180 * @return the address of the first skipped byte or NULL if there's less than @p n bytes left
|
|
|
181 */
|
|
|
182 static av_unused const uint8_t* skip_bytes(CABACContext *c, int n) {
|
|
|
183 const uint8_t *ptr = c->bytestream;
|
|
|
184
|
|
|
185 if (c->low & 0x1)
|
|
|
186 ptr--;
|
|
|
187 #if CABAC_BITS == 16
|
|
|
188 if (c->low & 0x1FF)
|
|
|
189 ptr--;
|
|
|
190 #endif
|
|
|
191 if ((int) (c->bytestream_end - ptr) < n)
|
|
|
192 return NULL;
|
|
|
193 ff_init_cabac_decoder(c, ptr + n, c->bytestream_end - ptr - n);
|
|
|
194
|
|
|
195 return ptr;
|
|
|
196 }
|
|
|
197
|
|
|
198 #endif /* AVCODEC_CABAC_FUNCTIONS_H */
|
