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TMessagesProj/jni/voip/webrtc/common_video/h265/h265_common.h

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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;
+
+// The size of the NALU type byte (2).
+const size_t kNaluTypeSize = 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,
+  // Aggregation packets, refer to section 4.4.2 in RFC 7798.
+  kAp = 48,
+  // Fragmentation units, refer to section 4.4.3 in RFC 7798.
+  kFu = 49,
+  // PACI packets, refer to section 4.4.4 in RFC 7798.
+  kPaci = 50
+};
+
+// Slice type definition. See table 7-7 of the H.265 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 H.265 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);
+uint32_t Log2(uint32_t value);
+
+}  // namespace H265
+}  // namespace webrtc
+
+#endif  // COMMON_VIDEO_H265_H265_COMMON_H_