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Diffstat (limited to '')
-rw-r--r-- | media/ffvpx/libavcodec/av1_parse.h | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/media/ffvpx/libavcodec/av1_parse.h b/media/ffvpx/libavcodec/av1_parse.h new file mode 100644 index 0000000000..f4a5d2830e --- /dev/null +++ b/media/ffvpx/libavcodec/av1_parse.h @@ -0,0 +1,184 @@ +/* + * AV1 common parsing code + * + * This file is part of FFmpeg. + * + * FFmpeg is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * FFmpeg is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with FFmpeg; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#ifndef AVCODEC_AV1_PARSE_H +#define AVCODEC_AV1_PARSE_H + +#include <limits.h> +#include <stdint.h> + +#include "libavutil/error.h" +#include "libavutil/intmath.h" +#include "libavutil/macros.h" + +#include "av1.h" +#include "get_bits.h" + +// OBU header fields + max leb128 length +#define MAX_OBU_HEADER_SIZE (2 + 8) + +typedef struct AV1OBU { + /** Size of payload */ + int size; + const uint8_t *data; + + /** + * Size, in bits, of just the data, excluding the trailing_one_bit and + * any trailing padding. + */ + int size_bits; + + /** Size of entire OBU, including header */ + int raw_size; + const uint8_t *raw_data; + + /** GetBitContext initialized to the start of the payload */ + GetBitContext gb; + + int type; + + int temporal_id; + int spatial_id; +} AV1OBU; + +/** An input packet split into OBUs */ +typedef struct AV1Packet { + AV1OBU *obus; + int nb_obus; + int obus_allocated; + unsigned obus_allocated_size; +} AV1Packet; + +/** + * Extract an OBU from a raw bitstream. + * + * @note This function does not copy or store any bitstream data. All + * the pointers in the AV1OBU structure will be valid as long + * as the input buffer also is. + */ +int ff_av1_extract_obu(AV1OBU *obu, const uint8_t *buf, int length, + void *logctx); + +/** + * Split an input packet into OBUs. + * + * @note This function does not copy or store any bitstream data. All + * the pointers in the AV1Packet structure will be valid as + * long as the input buffer also is. + */ +int ff_av1_packet_split(AV1Packet *pkt, const uint8_t *buf, int length, + void *logctx); + +/** + * Free all the allocated memory in the packet. + */ +void ff_av1_packet_uninit(AV1Packet *pkt); + +static inline int64_t leb128(GetBitContext *gb) { + int64_t ret = 0; + int i; + + for (i = 0; i < 8; i++) { + int byte = get_bits(gb, 8); + ret |= (int64_t)(byte & 0x7f) << (i * 7); + if (!(byte & 0x80)) + break; + } + return ret; +} + +static inline int parse_obu_header(const uint8_t *buf, int buf_size, + int64_t *obu_size, int *start_pos, int *type, + int *temporal_id, int *spatial_id) +{ + GetBitContext gb; + int ret, extension_flag, has_size_flag; + int64_t size; + + ret = init_get_bits8(&gb, buf, FFMIN(buf_size, MAX_OBU_HEADER_SIZE)); + if (ret < 0) + return ret; + + if (get_bits1(&gb) != 0) // obu_forbidden_bit + return AVERROR_INVALIDDATA; + + *type = get_bits(&gb, 4); + extension_flag = get_bits1(&gb); + has_size_flag = get_bits1(&gb); + skip_bits1(&gb); // obu_reserved_1bit + + if (extension_flag) { + *temporal_id = get_bits(&gb, 3); + *spatial_id = get_bits(&gb, 2); + skip_bits(&gb, 3); // extension_header_reserved_3bits + } else { + *temporal_id = *spatial_id = 0; + } + + *obu_size = has_size_flag ? leb128(&gb) + : buf_size - 1 - extension_flag; + + if (get_bits_left(&gb) < 0) + return AVERROR_INVALIDDATA; + + *start_pos = get_bits_count(&gb) / 8; + + size = *obu_size + *start_pos; + + if (size > buf_size) + return AVERROR_INVALIDDATA; + + return size; +} + +static inline int get_obu_bit_length(const uint8_t *buf, int size, int type) +{ + int v; + + /* There are no trailing bits on these */ + if (type == AV1_OBU_TILE_GROUP || + type == AV1_OBU_TILE_LIST || + type == AV1_OBU_FRAME) { + if (size > INT_MAX / 8) + return AVERROR(ERANGE); + else + return size * 8; + } + + while (size > 0 && buf[size - 1] == 0) + size--; + + if (!size) + return 0; + + v = buf[size - 1]; + + if (size > INT_MAX / 8) + return AVERROR(ERANGE); + size *= 8; + + /* Remove the trailing_one_bit and following trailing zeros */ + if (v) + size -= ff_ctz(v) + 1; + + return size; +} + +#endif /* AVCODEC_AV1_PARSE_H */ |