h265_pps_parser.h - mozsearch

/*

 *  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_PPS_PARSER_H_

#define COMMON_VIDEO_H265_H265_PPS_PARSER_H_

#include "absl/types/optional.h"

#include "api/array_view.h"

#include "common_video/h265/h265_sps_parser.h"

#include "rtc_base/bitstream_reader.h"

#include "rtc_base/system/rtc_export.h"

namespace webrtc {

// A class for parsing out picture parameter set (PPS) data from a H265 NALU.

class RTC_EXPORT H265PpsParser {

 public:

  // The parsed state of the PPS. Only some select values are stored.

  // Add more as they are actually needed.

  struct PpsState {

    PpsState() = default;

    bool dependent_slice_segments_enabled_flag = false;

    bool cabac_init_present_flag = false;

    bool output_flag_present_flag = false;

    uint32_t num_extra_slice_header_bits = 0;

    uint32_t num_ref_idx_l0_default_active_minus1 = 0;

    uint32_t num_ref_idx_l1_default_active_minus1 = 0;

    int init_qp_minus26 = 0;

    bool weighted_pred_flag = false;

    bool weighted_bipred_flag = false;

    bool lists_modification_present_flag = false;

    uint32_t pps_id = 0;

    uint32_t sps_id = 0;

    int qp_bd_offset_y = 0;

};

  // Unpack RBSP and parse PPS state from the supplied buffer.

  static absl::optional<PpsState> ParsePps(rtc::ArrayView<const uint8_t> data,

                                           const H265SpsParser::SpsState* sps);

  // TODO: bugs.webrtc.org/42225170 - Deprecate.

  static inline absl::optional<PpsState> ParsePps(

      const uint8_t* data,

      size_t length,

      const H265SpsParser::SpsState* sps) {

    return ParsePps(rtc::MakeArrayView(data, length), sps);

  static bool ParsePpsIds(rtc::ArrayView<const uint8_t> data,

                          uint32_t* pps_id,

                          uint32_t* sps_id);

  // TODO: bugs.webrtc.org/42225170 - Deprecate.

  static inline bool ParsePpsIds(const uint8_t* data,

                                 size_t length,

                                 uint32_t* pps_id,

                                 uint32_t* sps_id) {

    return ParsePpsIds(rtc::MakeArrayView(data, length), pps_id, sps_id);

 protected:

  // Parse the PPS state, for a bit buffer where RBSP decoding has already been

  // performed.

  static absl::optional<PpsState> ParseInternal(

      rtc::ArrayView<const uint8_t> buffer,

      const H265SpsParser::SpsState* sps);

  static bool ParsePpsIdsInternal(BitstreamReader& reader,

                                  uint32_t& pps_id,

                                  uint32_t& sps_id);

};

}  // namespace webrtc

#endif  // COMMON_VIDEO_H265_H265_PPS_PARSER_H_