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
|
/**************************************************************************
*
* Copyright 2013 Advanced Micro Devices, Inc.
* All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sub license, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial portions
* of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
* IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR
* ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
**************************************************************************/
/*
* Authors:
* Christian König <christian.koenig@amd.com>
*
*/
/*
* Functions for reading the raw byte sequence payload of H.264
*/
#ifndef vl_rbsp_h
#define vl_rbsp_h
#include "vl/vl_vlc.h"
struct vl_rbsp {
struct vl_vlc nal;
unsigned escaped;
};
/**
* Initialize the RBSP object
*/
static inline void vl_rbsp_init(struct vl_rbsp *rbsp, struct vl_vlc *nal, unsigned num_bits)
{
unsigned valid, bits_left = vl_vlc_bits_left(nal);
int i;
/* copy the position */
rbsp->nal = *nal;
rbsp->escaped = 16;
/* search for the end of the NAL unit */
while (vl_vlc_search_byte(nal, num_bits, 0x00)) {
if (vl_vlc_peekbits(nal, 24) == 0x000001 ||
vl_vlc_peekbits(nal, 32) == 0x00000001) {
vl_vlc_limit(&rbsp->nal, bits_left - vl_vlc_bits_left(nal));
break;
}
vl_vlc_eatbits(nal, 8);
}
valid = vl_vlc_valid_bits(&rbsp->nal);
/* search for the emulation prevention three byte */
for (i = 24; i <= valid; i += 8) {
if ((vl_vlc_peekbits(&rbsp->nal, i) & 0xffffff) == 0x3) {
vl_vlc_removebits(&rbsp->nal, i - 8, 8);
i += 8;
}
}
}
/**
* Make at least 16 more bits available
*/
static inline void vl_rbsp_fillbits(struct vl_rbsp *rbsp)
{
unsigned valid = vl_vlc_valid_bits(&rbsp->nal);
unsigned i, bits;
/* abort if we still have enough bits */
if (valid >= 32)
return;
vl_vlc_fillbits(&rbsp->nal);
/* abort if we have less than 24 bits left in this nal */
if (vl_vlc_bits_left(&rbsp->nal) < 24)
return;
/* check that we have enough bits left from the last fillbits */
assert(valid >= rbsp->escaped);
/* handle the already escaped bits */
valid -= rbsp->escaped;
/* search for the emulation prevention three byte */
rbsp->escaped = 16;
bits = vl_vlc_valid_bits(&rbsp->nal);
for (i = valid + 24; i <= bits; i += 8) {
if ((vl_vlc_peekbits(&rbsp->nal, i) & 0xffffff) == 0x3) {
vl_vlc_removebits(&rbsp->nal, i - 8, 8);
rbsp->escaped = bits - i;
bits -= 8;
i += 8;
}
}
}
/**
* Return an unsigned integer from the first n bits
*/
static inline unsigned vl_rbsp_u(struct vl_rbsp *rbsp, unsigned n)
{
if (n == 0)
return 0;
vl_rbsp_fillbits(rbsp);
return vl_vlc_get_uimsbf(&rbsp->nal, n);
}
/**
* Return an unsigned exponential Golomb encoded integer
*/
static inline unsigned vl_rbsp_ue(struct vl_rbsp *rbsp)
{
unsigned bits = 0;
vl_rbsp_fillbits(rbsp);
while (!vl_vlc_get_uimsbf(&rbsp->nal, 1))
++bits;
return (1 << bits) - 1 + vl_rbsp_u(rbsp, bits);
}
/**
* Return an signed exponential Golomb encoded integer
*/
static inline signed vl_rbsp_se(struct vl_rbsp *rbsp)
{
signed codeNum = vl_rbsp_ue(rbsp);
if (codeNum & 1)
return (codeNum + 1) >> 1;
else
return -(codeNum >> 1);
}
/**
* Are more data available in the RBSP ?
*/
static inline bool vl_rbsp_more_data(struct vl_rbsp *rbsp)
{
unsigned bits, value;
if (vl_vlc_bits_left(&rbsp->nal) > 8)
return TRUE;
bits = vl_vlc_valid_bits(&rbsp->nal);
value = vl_vlc_peekbits(&rbsp->nal, bits);
if (value == 0 || value == (1 << (bits - 1)))
return FALSE;
return TRUE;
}
#endif /* vl_rbsp_h */
|
