| /* |
| * 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 |
| */ |
| |
| /** |
| * @file |
| * EVC decoder/parser shared code |
| */ |
| |
| #ifndef AVCODEC_EVC_PARSE_H |
| #define AVCODEC_EVC_PARSE_H |
| |
| #include <stdint.h> |
| |
| #include "libavutil/intreadwrite.h" |
| #include "libavutil/log.h" |
| #include "evc.h" |
| #include "evc_ps.h" |
| |
| // The sturcture reflects Slice Header RBSP(raw byte sequence payload) layout |
| // @see ISO_IEC_23094-1 section 7.3.2.6 |
| // |
| // The following descriptors specify the parsing process of each element |
| // u(n) - unsigned integer using n bits |
| // ue(v) - unsigned integer 0-th order Exp_Golomb-coded syntax element with the left bit first |
| // u(n) - unsigned integer using n bits. |
| // When n is "v" in the syntax table, the number of bits varies in a manner dependent on the value of other syntax elements. |
| typedef struct EVCParserSliceHeader { |
| uint8_t slice_pic_parameter_set_id; // ue(v) |
| uint8_t single_tile_in_slice_flag; // u(1) |
| uint8_t first_tile_id; // u(v) |
| uint8_t arbitrary_slice_flag; // u(1) |
| uint8_t last_tile_id; // u(v) |
| uint32_t num_remaining_tiles_in_slice_minus1; // ue(v) |
| uint16_t delta_tile_id_minus1[EVC_MAX_TILE_ROWS * EVC_MAX_TILE_COLUMNS]; // ue(v) |
| |
| uint8_t slice_type; // ue(v) |
| uint8_t no_output_of_prior_pics_flag; // u(1) |
| uint8_t mmvd_group_enable_flag; // u(1) |
| uint8_t slice_alf_enabled_flag; // u(1) |
| |
| uint8_t slice_alf_luma_aps_id; // u(5) |
| uint8_t slice_alf_map_flag; // u(1) |
| uint8_t slice_alf_chroma_idc; // u(2) |
| uint8_t slice_alf_chroma_aps_id; // u(5) |
| uint8_t slice_alf_chroma_map_flag; // u(1) |
| uint8_t slice_alf_chroma2_aps_id; // u(5) |
| uint8_t slice_alf_chroma2_map_flag; // u(1) |
| uint16_t slice_pic_order_cnt_lsb; // u(v) |
| |
| // @note |
| // Currently the structure does not reflect the entire Slice Header RBSP layout. |
| // It contains only the fields that are necessary to read from the NAL unit all the values |
| // necessary for the correct initialization of the AVCodecContext structure. |
| |
| // @note |
| // If necessary, add the missing fields to the structure to reflect |
| // the contents of the entire NAL unit of the SPS type |
| |
| } EVCParserSliceHeader; |
| |
| // picture order count of the current picture |
| typedef struct EVCParserPoc { |
| int PicOrderCntVal; // current picture order count value |
| int prevPicOrderCntVal; // the picture order count of the previous Tid0 picture |
| int DocOffset; // the decoding order count of the previous picture |
| } EVCParserPoc; |
| |
| static inline uint32_t evc_read_nal_unit_length(const uint8_t *bits, int bits_size, void *logctx) |
| { |
| uint32_t nalu_len = 0; |
| |
| if (bits_size < EVC_NALU_LENGTH_PREFIX_SIZE) { |
| av_log(logctx, AV_LOG_ERROR, "Can't read NAL unit length\n"); |
| return 0; |
| } |
| |
| nalu_len = AV_RB32(bits); |
| |
| return nalu_len; |
| } |
| |
| int ff_evc_parse_slice_header(GetBitContext *gb, EVCParserSliceHeader *sh, |
| const EVCParamSets *ps, enum EVCNALUnitType nalu_type); |
| |
| // POC (picture order count of the current picture) derivation |
| // @see ISO/IEC 23094-1:2020(E) 8.3.1 Decoding process for picture order count |
| int ff_evc_derive_poc(const EVCParamSets *ps, const EVCParserSliceHeader *sh, |
| EVCParserPoc *poc, enum EVCNALUnitType nalu_type, int tid); |
| |
| #endif /* AVCODEC_EVC_PARSE_H */ |
