2 * AV1 common parsing code
4 * This file is part of FFmpeg.
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.
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.
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
21 #ifndef AVCODEC_AV1_PARSE_H
22 #define AVCODEC_AV1_PARSE_H
30 typedef struct AV1OBU {
31 /** Size of payload */
36 * Size, in bits, of just the data, excluding the trailing_one_bit and
37 * any trailing padding.
41 /** Size of entire OBU, including header */
43 const uint8_t *raw_data;
45 /** GetBitContext initialized to the start of the payload */
54 /** An input packet split into OBUs */
55 typedef struct AV1Packet {
62 * Extract an OBU from a raw bitstream.
64 * @note This function does not copy or store any bitstream data. All
65 * the pointers in the AV1OBU structure will be valid as long
66 * as the input buffer also is.
68 int ff_av1_extract_obu(AV1OBU *obu, const uint8_t *buf, int length,
72 * Split an input packet into OBUs.
74 * @note This function does not copy or store any bitstream data. All
75 * the pointers in the AV1Packet structure will be valid as
76 * long as the input buffer also is.
78 int ff_av1_packet_split(AV1Packet *pkt, const uint8_t *buf, int length,
82 * Free all the allocated memory in the packet.
84 void ff_av1_packet_uninit(AV1Packet *pkt);
86 static inline int64_t leb128(GetBitContext *gb) {
90 for (i = 0; i < 8; i++) {
91 int byte = get_bits(gb, 8);
92 ret |= (int64_t)(byte & 0x7f) << (i * 7);
99 static inline int parse_obu_header(const uint8_t *buf, int buf_size,
100 int64_t *obu_size, int *start_pos, int *type,
101 int *temporal_id, int *spatial_id)
104 int ret, extension_flag, has_size_flag;
107 ret = init_get_bits8(&gb, buf, FFMIN(buf_size, 2 + 8)); // OBU header fields + max leb128 length
111 if (get_bits1(&gb) != 0) // obu_forbidden_bit
112 return AVERROR_INVALIDDATA;
114 *type = get_bits(&gb, 4);
115 extension_flag = get_bits1(&gb);
116 has_size_flag = get_bits1(&gb);
117 skip_bits1(&gb); // obu_reserved_1bit
119 if (extension_flag) {
120 *temporal_id = get_bits(&gb, 3);
121 *spatial_id = get_bits(&gb, 2);
122 skip_bits(&gb, 3); // extension_header_reserved_3bits
124 *temporal_id = *spatial_id = 0;
127 *obu_size = has_size_flag ? leb128(&gb)
128 : buf_size - 1 - extension_flag;
130 if (get_bits_left(&gb) < 0)
131 return AVERROR_INVALIDDATA;
133 *start_pos = get_bits_count(&gb) / 8;
135 size = *obu_size + *start_pos;
138 return AVERROR_INVALIDDATA;
143 static inline int get_obu_bit_length(const uint8_t *buf, int size, int type)
147 /* There are no trailing bits on these */
148 if (type == AV1_OBU_TILE_GROUP || type == AV1_OBU_FRAME) {
149 if (size > INT_MAX / 8)
150 return AVERROR(ERANGE);
155 while (size > 0 && buf[size - 1] == 0)
163 if (size > INT_MAX / 8)
164 return AVERROR(ERANGE);
167 /* Remove the trailing_one_bit and following trailing zeros */
169 size -= ff_ctz(v) + 1;
174 #endif /* AVCODEC_AV1_PARSE_H */