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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_COMMON_H_
#define COMMON_VIDEO_H265_H265_COMMON_H_
#include <memory>
#include <vector>
#include "common_video/h265/h265_inline.h"
#include "rtc_base/buffer.h"
namespace webrtc {
namespace H265 {
// The size of a full NALU start sequence {0 0 0 1}, used for the first NALU
// of an access unit, and for SPS and PPS blocks.
constexpr size_t kNaluLongStartSequenceSize = 4;
// The size of a shortened NALU start sequence {0 0 1}, that may be used if
// not the first NALU of an access unit or an SPS or PPS block.
constexpr size_t kNaluShortStartSequenceSize = 3;
// The size of the NALU header byte (2).
constexpr size_t kNaluHeaderSize = 2;
// Type description of 0-40 is defined in Table7-1 of the H.265 spec
// Type desciption of 48-49 is defined in section 4.4.2 and 4.4.3 of RFC7798
enum NaluType : uint8_t {
kTrailN = 0,
kTrailR = 1,
kTsaN = 2,
kTsaR = 3,
kStsaN = 4,
kStsaR = 5,
kRadlN = 6,
kRadlR = 7,
kBlaWLp = 16,
kBlaWRadl = 17,
kBlaNLp = 18,
kIdrWRadl = 19,
kIdrNLp = 20,
kCra = 21,
kRsvIrapVcl23 = 23,
kVps = 32,
kSps = 33,
kPps = 34,
kAud = 35,
kPrefixSei = 39,
kSuffixSei = 40,
kAP = 48,
kFU = 49
};
// Slice type definition. See table 7-7 of the H265 spec
enum SliceType : uint8_t { kB = 0, kP = 1, kI = 2 };
struct NaluIndex {
// Start index of NALU, including start sequence.
size_t start_offset = 0;
// Start index of NALU payload, typically type header.
size_t payload_start_offset = 0;
// Length of NALU payload, in bytes, counting from payload_start_offset.
size_t payload_size = 0;
};
// Returns a vector of the NALU indices in the given buffer.
std::vector<NaluIndex> FindNaluIndices(const uint8_t* buffer,
size_t buffer_size);
// Get the NAL type from the header byte immediately following start sequence.
NaluType ParseNaluType(uint8_t data);
// Methods for parsing and writing RBSP. See section 7.4.2 of the H265 spec.
//
// The following sequences are illegal, and need to be escaped when encoding:
// 00 00 00 -> 00 00 03 00
// 00 00 01 -> 00 00 03 01
// 00 00 02 -> 00 00 03 02
// And things in the source that look like the emulation byte pattern (00 00 03)
// need to have an extra emulation byte added, so it's removed when decoding:
// 00 00 03 -> 00 00 03 03
//
// Decoding is simply a matter of finding any 00 00 03 sequence and removing
// the 03 emulation byte.
// Parse the given data and remove any emulation byte escaping.
std::vector<uint8_t> ParseRbsp(const uint8_t* data, size_t length);
// Write the given data to the destination buffer, inserting and emulation
// bytes in order to escape any data the could be interpreted as a start
// sequence.
void WriteRbsp(const uint8_t* bytes, size_t length, rtc::Buffer* destination);
uint32_t Log2Ceiling(uint32_t value);
} // namespace H265
} // namespace webrtc
#endif // COMMON_VIDEO_H265_H265_COMMON_H_
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