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/*
* Copyright (c) 2015 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 WEBRTC_MODULES_RTP_RTCP_SOURCE_H264_BITSTREAM_PARSER_H_
#define WEBRTC_MODULES_RTP_RTCP_SOURCE_H264_BITSTREAM_PARSER_H_
#include <stdint.h>
#include <stddef.h>
namespace rtc {
class BitBuffer;
}
namespace webrtc {
// Stateful H264 bitstream parser (due to SPS/PPS). Used to parse out QP values
// from the bitstream.
// TODO(pbos): Unify with RTP SPS parsing and only use one H264 parser.
// TODO(pbos): If/when this gets used on the receiver side CHECKs must be
// removed and gracefully abort as we have no control over receive-side
// bitstreams.
class H264BitstreamParser {
public:
// Parse an additional chunk of H264 bitstream.
void ParseBitstream(const uint8_t* bitstream, size_t length);
// Get the last extracted QP value from the parsed bitstream.
bool GetLastSliceQp(int* qp) const;
private:
// Captured in SPS and used when parsing slice NALUs.
struct SpsState {
SpsState();
uint32_t delta_pic_order_always_zero_flag = 0;
uint32_t separate_colour_plane_flag = 0;
uint32_t frame_mbs_only_flag = 0;
uint32_t log2_max_frame_num_minus4 = 0;
uint32_t log2_max_pic_order_cnt_lsb_minus4 = 0;
uint32_t pic_order_cnt_type = 0;
};
struct PpsState {
PpsState();
bool bottom_field_pic_order_in_frame_present_flag = false;
bool weighted_pred_flag = false;
uint32_t weighted_bipred_idc = false;
uint32_t redundant_pic_cnt_present_flag = 0;
int pic_init_qp_minus26 = 0;
};
void ParseSlice(const uint8_t* slice, size_t length);
bool ParseSpsNalu(const uint8_t* sps_nalu, size_t length);
bool ParsePpsNalu(const uint8_t* pps_nalu, size_t length);
bool ParseNonParameterSetNalu(const uint8_t* source,
size_t source_length,
uint8_t nalu_type);
// SPS/PPS state, updated when parsing new SPS/PPS, used to parse slices.
bool sps_parsed_ = false;
SpsState sps_;
bool pps_parsed_ = false;
PpsState pps_;
// Last parsed slice QP.
bool last_slice_qp_delta_parsed_ = false;
int32_t last_slice_qp_delta_ = 0;
};
} // namespace webrtc
#endif // WEBRTC_MODULES_RTP_RTCP_SOURCE_H264_BITSTREAM_PARSER_H_
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