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
29 typedef struct AV1OBU {
30 /** Size of payload */
34 /** Size of entire OBU, including header */
36 const uint8_t *raw_data;
38 /** GetBitContext initialized to the start of the payload */
47 /** An input packet split into OBUs */
48 typedef struct AV1Packet {
55 * Extract an OBU from a raw bitstream.
57 * @note This function does not copy or store any bistream data. All
58 * the pointers in the AV1OBU structure will be valid as long
59 * as the input buffer also is.
61 int ff_av1_extract_obu(AV1OBU *obu, const uint8_t *buf, int length,
65 * Split an input packet into OBUs.
67 * @note This function does not copy or store any bistream data. All
68 * the pointers in the AV1Packet structure will be valid as
69 * long as the input buffer also is.
71 int ff_av1_packet_split(AV1Packet *pkt, const uint8_t *buf, int length,
75 * Free all the allocated memory in the packet.
77 void ff_av1_packet_uninit(AV1Packet *pkt);
79 static inline int64_t leb128(GetBitContext *gb) {
83 for (i = 0; i < 8; i++) {
84 int byte = get_bits(gb, 8);
85 ret |= (int64_t)(byte & 0x7f) << (i * 7);
92 static inline int parse_obu_header(const uint8_t *buf, int buf_size,
93 int64_t *obu_size, int *start_pos, int *type,
94 int *temporal_id, int *spatial_id)
97 int ret, extension_flag, has_size_flag;
100 ret = init_get_bits8(&gb, buf, FFMIN(buf_size, 2 + 8)); // OBU header fields + max leb128 length
104 if (get_bits1(&gb) != 0) // obu_forbidden_bit
105 return AVERROR_INVALIDDATA;
107 *type = get_bits(&gb, 4);
108 extension_flag = get_bits1(&gb);
109 has_size_flag = get_bits1(&gb);
110 skip_bits1(&gb); // obu_reserved_1bit
112 if (extension_flag) {
113 *temporal_id = get_bits(&gb, 3);
114 *spatial_id = get_bits(&gb, 2);
115 skip_bits(&gb, 3); // extension_header_reserved_3bits
117 *temporal_id = *spatial_id = 0;
120 *obu_size = has_size_flag ? leb128(&gb)
121 : buf_size - 1 - extension_flag;
123 if (get_bits_left(&gb) < 0)
124 return AVERROR_INVALIDDATA;
126 *start_pos = get_bits_count(&gb) / 8;
128 size = *obu_size + *start_pos;
131 return AVERROR(ERANGE);
136 #endif /* AVCODEC_AV1_PARSE_H */