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/*
* Copyright (c) 2023 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef COMMON_VIDEO_H265_H265_SPS_PARSER_H_
#define COMMON_VIDEO_H265_H265_SPS_PARSER_H_
#include <vector>
#include "absl/types/optional.h"
#include "api/array_view.h"
#include "rtc_base/bitstream_reader.h"
namespace webrtc {
// For explanations of each struct and its members, see H.265 specification
// at http://www.itu.int/rec/T-REC-H.265.
enum {
kMaxLongTermRefPicSets = 32, // 7.4.3.2.1
kMaxShortTermRefPicSets = 64, // 7.4.3.2.1
kMaxSubLayers = 7, // 7.4.3.1 & 7.4.3.2.1 [v|s]ps_max_sub_layers_minus1 + 1
};
enum H265ProfileIdc {
kProfileIdcMain = 1,
kProfileIdcMain10 = 2,
kProfileIdcMainStill = 3,
kProfileIdcRangeExtensions = 4,
kProfileIdcHighThroughput = 5,
kProfileIdcMultiviewMain = 6,
kProfileIdcScalableMain = 7,
kProfileIdc3dMain = 8,
kProfileIdcScreenContentCoding = 9,
kProfileIdcScalableRangeExtensions = 10,
kProfileIdcHighThroughputScreenContentCoding = 11,
};
// A class for parsing out sequence parameter set (SPS) data from an H265 NALU.
class H265SpsParser {
public:
struct ProfileTierLevel {
ProfileTierLevel();
// Syntax elements.
int general_profile_idc = 0;
int general_level_idc = 0; // 30x the actual level.
uint32_t general_profile_compatibility_flags = 0;
bool general_progressive_source_flag = false;
bool general_interlaced_source_flag = false;
bool general_non_packed_constraint_flag = false;
bool general_frame_only_constraint_flag = false;
bool general_one_picture_only_constraint_flag = false;
};
struct ShortTermRefPicSet {
ShortTermRefPicSet();
// Syntax elements.
uint32_t num_negative_pics = 0;
uint32_t num_positive_pics = 0;
uint32_t delta_poc_s0[kMaxShortTermRefPicSets] = {};
uint32_t used_by_curr_pic_s0[kMaxShortTermRefPicSets] = {};
uint32_t delta_poc_s1[kMaxShortTermRefPicSets] = {};
uint32_t used_by_curr_pic_s1[kMaxShortTermRefPicSets] = {};
// Calculated fields.
uint32_t num_delta_pocs = 0;
};
// The parsed state of the SPS. Only some select values are stored.
// Add more as they are actually needed.
struct SpsState {
SpsState() = default;
uint32_t sps_max_sub_layers_minus1 = 0;
uint32_t chroma_format_idc = 0;
uint32_t separate_colour_plane_flag = 0;
uint32_t pic_width_in_luma_samples = 0;
uint32_t pic_height_in_luma_samples = 0;
uint32_t log2_max_pic_order_cnt_lsb_minus4 = 0;
uint32_t sps_max_dec_pic_buffering_minus1[kMaxSubLayers] = {};
uint32_t log2_min_luma_coding_block_size_minus3 = 0;
uint32_t log2_diff_max_min_luma_coding_block_size = 0;
uint32_t sample_adaptive_offset_enabled_flag = 0;
uint32_t num_short_term_ref_pic_sets = 0;
std::vector<H265SpsParser::ShortTermRefPicSet> short_term_ref_pic_set;
uint32_t long_term_ref_pics_present_flag = 0;
uint32_t num_long_term_ref_pics_sps = 0;
std::vector<uint32_t> used_by_curr_pic_lt_sps_flag;
uint32_t sps_temporal_mvp_enabled_flag = 0;
uint32_t width = 0;
uint32_t height = 0;
uint32_t sps_id = 0;
uint32_t vps_id = 0;
uint32_t pic_width_in_ctbs_y = 0;
uint32_t pic_height_in_ctbs_y = 0;
uint32_t bit_depth_luma_minus8 = 0;
};
// Unpack RBSP and parse SPS state from the supplied buffer.
static absl::optional<SpsState> ParseSps(const uint8_t* data, size_t length);
static bool ParseScalingListData(BitstreamReader& reader);
static absl::optional<ShortTermRefPicSet> ParseShortTermRefPicSet(
uint32_t st_rps_idx,
uint32_t num_short_term_ref_pic_sets,
const std::vector<ShortTermRefPicSet>& ref_pic_sets,
uint32_t sps_max_dec_pic_buffering_minus1,
BitstreamReader& reader);
static absl::optional<H265SpsParser::ProfileTierLevel> ParseProfileTierLevel(
bool profile_present,
int max_num_sub_layers_minus1,
BitstreamReader& reader);
protected:
// Parse the SPS state, for a bit buffer where RBSP decoding has already been
// performed.
static absl::optional<SpsState> ParseSpsInternal(
rtc::ArrayView<const uint8_t> buffer);
static bool ParseProfileTierLevel(BitstreamReader& reader,
uint32_t sps_max_sub_layers_minus1);
// From Table A.8 - General tier and level limits.
static int GetMaxLumaPs(int general_level_idc);
// From A.4.2 - Profile-specific level limits for the video profiles.
static size_t GetDpbMaxPicBuf(int general_profile_idc);
};
} // namespace webrtc
#endif // COMMON_VIDEO_H265_H265_SPS_PARSER_H_