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 // OBU header fields + max leb128 length
31 #define MAX_OBU_HEADER_SIZE (2 + 8)
33 typedef struct AV1OBU {
34 /** Size of payload */
39 * Size, in bits, of just the data, excluding the trailing_one_bit and
40 * any trailing padding.
44 /** Size of entire OBU, including header */
46 const uint8_t *raw_data;
48 /** GetBitContext initialized to the start of the payload */
57 /** An input packet split into OBUs */
58 typedef struct AV1Packet {
62 unsigned obus_allocated_size;
66 * Extract an OBU from a raw bitstream.
68 * @note This function does not copy or store any bitstream data. All
69 * the pointers in the AV1OBU structure will be valid as long
70 * as the input buffer also is.
72 int ff_av1_extract_obu(AV1OBU *obu, const uint8_t *buf, int length,
76 * Split an input packet into OBUs.
78 * @note This function does not copy or store any bitstream data. All
79 * the pointers in the AV1Packet structure will be valid as
80 * long as the input buffer also is.
82 int ff_av1_packet_split(AV1Packet *pkt, const uint8_t *buf, int length,
86 * Free all the allocated memory in the packet.
88 void ff_av1_packet_uninit(AV1Packet *pkt);
90 static inline int64_t leb128(GetBitContext *gb) {
94 for (i = 0; i < 8; i++) {
95 int byte = get_bits(gb, 8);
96 ret |= (int64_t)(byte & 0x7f) << (i * 7);
103 static inline int parse_obu_header(const uint8_t *buf, int buf_size,
104 int64_t *obu_size, int *start_pos, int *type,
105 int *temporal_id, int *spatial_id)
108 int ret, extension_flag, has_size_flag;
111 ret = init_get_bits8(&gb, buf, FFMIN(buf_size, MAX_OBU_HEADER_SIZE));
115 if (get_bits1(&gb) != 0) // obu_forbidden_bit
116 return AVERROR_INVALIDDATA;
118 *type = get_bits(&gb, 4);
119 extension_flag = get_bits1(&gb);
120 has_size_flag = get_bits1(&gb);
121 skip_bits1(&gb); // obu_reserved_1bit
123 if (extension_flag) {
124 *temporal_id = get_bits(&gb, 3);
125 *spatial_id = get_bits(&gb, 2);
126 skip_bits(&gb, 3); // extension_header_reserved_3bits
128 *temporal_id = *spatial_id = 0;
131 *obu_size = has_size_flag ? leb128(&gb)
132 : buf_size - 1 - extension_flag;
134 if (get_bits_left(&gb) < 0)
135 return AVERROR_INVALIDDATA;
137 *start_pos = get_bits_count(&gb) / 8;
139 size = *obu_size + *start_pos;
142 return AVERROR_INVALIDDATA;
147 static inline int get_obu_bit_length(const uint8_t *buf, int size, int type)
151 /* There are no trailing bits on these */
152 if (type == AV1_OBU_TILE_GROUP ||
153 type == AV1_OBU_TILE_LIST ||
154 type == AV1_OBU_FRAME) {
155 if (size > INT_MAX / 8)
156 return AVERROR(ERANGE);
161 while (size > 0 && buf[size - 1] == 0)
169 if (size > INT_MAX / 8)
170 return AVERROR(ERANGE);
173 /* Remove the trailing_one_bit and following trailing zeros */
175 size -= ff_ctz(v) + 1;
180 #endif /* AVCODEC_AV1_PARSE_H */