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/*
* Copyright (c) 2016 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_H264_PPS_PARSER_H_
#define COMMON_VIDEO_H264_PPS_PARSER_H_
#include <stddef.h>
#include <stdint.h>
#include <optional>
#include "api/array_view.h"
namespace webrtc {
// A class for parsing out picture parameter set (PPS) data from a H264 NALU.
class PpsParser {
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 bottom_field_pic_order_in_frame_present_flag = false;
bool weighted_pred_flag = false;
bool entropy_coding_mode_flag = false;
uint32_t num_ref_idx_l0_default_active_minus1 = 0;
uint32_t num_ref_idx_l1_default_active_minus1 = 0;
uint32_t weighted_bipred_idc = false;
uint32_t redundant_pic_cnt_present_flag = 0;
int pic_init_qp_minus26 = 0;
uint32_t id = 0;
uint32_t sps_id = 0;
};
struct SliceHeader {
SliceHeader() = default;
uint32_t first_mb_in_slice = 0;
uint32_t pic_parameter_set_id = 0;
};
// Unpack RBSP and parse PPS state from the supplied buffer.
static std::optional<PpsState> ParsePps(rtc::ArrayView<const uint8_t> data);
// TODO: bugs.webrtc.org/42225170 - Deprecate.
static inline std::optional<PpsState> ParsePps(const uint8_t* data,
size_t length) {
return ParsePps(rtc::MakeArrayView(data, length));
}
static bool ParsePpsIds(rtc::ArrayView<const uint8_t> data,
uint32_t* pps_id,
uint32_t* sps_id);
static std::optional<SliceHeader> ParseSliceHeader(
rtc::ArrayView<const uint8_t> data);
protected:
// Parse the PPS state, for a buffer where RBSP decoding has already been
// performed.
static std::optional<PpsState> ParseInternal(
rtc::ArrayView<const uint8_t> buffer);
};
} // namespace webrtc
#endif // COMMON_VIDEO_H264_PPS_PARSER_H_