FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavcodec/av1_parse.h
Date: 2021-09-23 20:34:37
Exec Total Coverage
Lines: 45 49 91.8%
Branches: 28 34 82.4%

Line Branch Exec Source
1 /*
2 * AV1 common parsing code
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21 #ifndef AVCODEC_AV1_PARSE_H
22 #define AVCODEC_AV1_PARSE_H
23
24 #include <limits.h>
25 #include <stdint.h>
26
27 #include "libavutil/common.h"
28 #include "libavutil/error.h"
29 #include "libavutil/intmath.h"
30
31 #include "av1.h"
32 #include "get_bits.h"
33
34 // OBU header fields + max leb128 length
35 #define MAX_OBU_HEADER_SIZE (2 + 8)
36
37 typedef struct AV1OBU {
38 /** Size of payload */
39 int size;
40 const uint8_t *data;
41
42 /**
43 * Size, in bits, of just the data, excluding the trailing_one_bit and
44 * any trailing padding.
45 */
46 int size_bits;
47
48 /** Size of entire OBU, including header */
49 int raw_size;
50 const uint8_t *raw_data;
51
52 /** GetBitContext initialized to the start of the payload */
53 GetBitContext gb;
54
55 int type;
56
57 int temporal_id;
58 int spatial_id;
59 } AV1OBU;
60
61 /** An input packet split into OBUs */
62 typedef struct AV1Packet {
63 AV1OBU *obus;
64 int nb_obus;
65 int obus_allocated;
66 unsigned obus_allocated_size;
67 } AV1Packet;
68
69 /**
70 * Extract an OBU from a raw bitstream.
71 *
72 * @note This function does not copy or store any bitstream data. All
73 * the pointers in the AV1OBU structure will be valid as long
74 * as the input buffer also is.
75 */
76 int ff_av1_extract_obu(AV1OBU *obu, const uint8_t *buf, int length,
77 void *logctx);
78
79 /**
80 * Split an input packet into OBUs.
81 *
82 * @note This function does not copy or store any bitstream data. All
83 * the pointers in the AV1Packet structure will be valid as
84 * long as the input buffer also is.
85 */
86 int ff_av1_packet_split(AV1Packet *pkt, const uint8_t *buf, int length,
87 void *logctx);
88
89 /**
90 * Free all the allocated memory in the packet.
91 */
92 void ff_av1_packet_uninit(AV1Packet *pkt);
93
94 3053 static inline int64_t leb128(GetBitContext *gb) {
95 3053 int64_t ret = 0;
96 int i;
97
98
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3626 for (i = 0; i < 8; i++) {
99 3620 int byte = get_bits(gb, 8);
100 3620 ret |= (int64_t)(byte & 0x7f) << (i * 7);
101
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3620 if (!(byte & 0x80))
102 3047 break;
103 }
104 3053 return ret;
105 }
106
107 1261 static inline int parse_obu_header(const uint8_t *buf, int buf_size,
108 int64_t *obu_size, int *start_pos, int *type,
109 int *temporal_id, int *spatial_id)
110 {
111 GetBitContext gb;
112 int ret, extension_flag, has_size_flag;
113 int64_t size;
114
115 1261 ret = init_get_bits8(&gb, buf, FFMIN(buf_size, MAX_OBU_HEADER_SIZE));
116
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1261 if (ret < 0)
117 return ret;
118
119
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1261 if (get_bits1(&gb) != 0) // obu_forbidden_bit
120 34 return AVERROR_INVALIDDATA;
121
122 1227 *type = get_bits(&gb, 4);
123 1227 extension_flag = get_bits1(&gb);
124 1227 has_size_flag = get_bits1(&gb);
125 1227 skip_bits1(&gb); // obu_reserved_1bit
126
127
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1227 if (extension_flag) {
128 1005 *temporal_id = get_bits(&gb, 3);
129 1005 *spatial_id = get_bits(&gb, 2);
130 1005 skip_bits(&gb, 3); // extension_header_reserved_3bits
131 } else {
132 222 *temporal_id = *spatial_id = 0;
133 }
134
135 1095 *obu_size = has_size_flag ? leb128(&gb)
136
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1227 : buf_size - 1 - extension_flag;
137
138
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1227 if (get_bits_left(&gb) < 0)
139 29 return AVERROR_INVALIDDATA;
140
141 1198 *start_pos = get_bits_count(&gb) / 8;
142
143 1198 size = *obu_size + *start_pos;
144
145
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1198 if (size > buf_size)
146 620 return AVERROR_INVALIDDATA;
147
148 578 return size;
149 }
150
151 78 static inline int get_obu_bit_length(const uint8_t *buf, int size, int type)
152 {
153 int v;
154
155 /* There are no trailing bits on these */
156
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78 if (type == AV1_OBU_TILE_GROUP ||
157
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65 type == AV1_OBU_TILE_LIST ||
158 type == AV1_OBU_FRAME) {
159
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29 if (size > INT_MAX / 8)
160 return AVERROR(ERANGE);
161 else
162 29 return size * 8;
163 }
164
165
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49 while (size > 0 && buf[size - 1] == 0)
166 size--;
167
168
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49 if (!size)
169 19 return 0;
170
171 30 v = buf[size - 1];
172
173
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30 if (size > INT_MAX / 8)
174 return AVERROR(ERANGE);
175 30 size *= 8;
176
177 /* Remove the trailing_one_bit and following trailing zeros */
178
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30 if (v)
179 30 size -= ff_ctz(v) + 1;
180
181 30 return size;
182 }
183
184 #endif /* AVCODEC_AV1_PARSE_H */
185