1 /*
2 * exp golomb vlc writing stuff
3 * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
4 * Copyright (c) 2004 Alex Beregszaszi
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 /**
24 * @file
25 * @brief
26 * exp golomb vlc writing stuff
27 * @author Michael Niedermayer <michaelni@gmx.at> and Alex Beregszaszi
28 */
29
30 #ifndef AVCODEC_PUT_GOLOMB_H
31 #define AVCODEC_PUT_GOLOMB_H
32
33 #include <stdint.h>
34 #include "put_bits.h"
35
36 extern const uint8_t ff_ue_golomb_len[256];
37
38 /**
39 * write unsigned exp golomb code. 2^16 - 2 at most
40 */
set_ue_golomb(PutBitContext * pb,int i)41 static inline void set_ue_golomb(PutBitContext *pb, int i)
42 {
43 av_assert2(i >= 0);
44 av_assert2(i <= 0xFFFE);
45
46 if (i < 256)
47 put_bits(pb, ff_ue_golomb_len[i], i + 1);
48 else {
49 int e = av_log2(i + 1);
50 put_bits(pb, 2 * e + 1, i + 1);
51 }
52 }
53
54 /**
55 * write unsigned exp golomb code. 2^32-2 at most.
56 */
set_ue_golomb_long(PutBitContext * pb,uint32_t i)57 static inline void set_ue_golomb_long(PutBitContext *pb, uint32_t i)
58 {
59 av_assert2(i <= (UINT32_MAX - 1));
60
61 if (i < 256)
62 put_bits(pb, ff_ue_golomb_len[i], i + 1);
63 else {
64 int e = av_log2(i + 1);
65 put_bits64(pb, 2 * e + 1, i + 1);
66 }
67 }
68
69 /**
70 * write truncated unsigned exp golomb code.
71 */
set_te_golomb(PutBitContext * pb,int i,int range)72 static inline void set_te_golomb(PutBitContext *pb, int i, int range)
73 {
74 av_assert2(range >= 1);
75 av_assert2(i <= range);
76
77 if (range == 2)
78 put_bits(pb, 1, i ^ 1);
79 else
80 set_ue_golomb(pb, i);
81 }
82
83 /**
84 * write signed exp golomb code. 16 bits at most.
85 */
set_se_golomb(PutBitContext * pb,int i)86 static inline void set_se_golomb(PutBitContext *pb, int i)
87 {
88 i = 2 * i - 1;
89 if (i < 0)
90 i ^= -1; //FIXME check if gcc does the right thing
91 set_ue_golomb(pb, i);
92 }
93
94 /**
95 * write unsigned golomb rice code (ffv1).
96 */
set_ur_golomb(PutBitContext * pb,int i,int k,int limit,int esc_len)97 static inline void set_ur_golomb(PutBitContext *pb, int i, int k, int limit,
98 int esc_len)
99 {
100 int e;
101
102 av_assert2(i >= 0);
103
104 e = i >> k;
105 if (e < limit)
106 put_bits(pb, e + k + 1, (1 << k) + av_mod_uintp2(i, k));
107 else
108 put_bits(pb, limit + esc_len, i - limit + 1);
109 }
110
111 /**
112 * write unsigned golomb rice code (jpegls).
113 */
set_ur_golomb_jpegls(PutBitContext * pb,int i,int k,int limit,int esc_len)114 static inline void set_ur_golomb_jpegls(PutBitContext *pb, int i, int k,
115 int limit, int esc_len)
116 {
117 int e;
118
119 av_assert2(i >= 0);
120
121 e = (i >> k) + 1;
122 if (e < limit) {
123 while (e > 31) {
124 put_bits(pb, 31, 0);
125 e -= 31;
126 }
127 put_bits(pb, e, 1);
128 if (k)
129 put_sbits(pb, k, i);
130 } else {
131 while (limit > 31) {
132 put_bits(pb, 31, 0);
133 limit -= 31;
134 }
135 put_bits(pb, limit, 1);
136 put_bits(pb, esc_len, i - 1);
137 }
138 }
139
140 /**
141 * write signed golomb rice code (ffv1).
142 */
set_sr_golomb(PutBitContext * pb,int i,int k,int limit,int esc_len)143 static inline void set_sr_golomb(PutBitContext *pb, int i, int k, int limit,
144 int esc_len)
145 {
146 int v;
147
148 v = -2 * i - 1;
149 v ^= (v >> 31);
150
151 set_ur_golomb(pb, v, k, limit, esc_len);
152 }
153
154 /**
155 * write signed golomb rice code (flac).
156 */
set_sr_golomb_flac(PutBitContext * pb,int i,int k,int limit,int esc_len)157 static inline void set_sr_golomb_flac(PutBitContext *pb, int i, int k,
158 int limit, int esc_len)
159 {
160 int v;
161
162 v = -2 * i - 1;
163 v ^= (v >> 31);
164
165 set_ur_golomb_jpegls(pb, v, k, limit, esc_len);
166 }
167
168 #endif /* AVCODEC_PUT_GOLOMB_H */
169