cd8b36bb9f
num_ref are represented using golomb and may be very large. BitstreamReader is generally resilent to many consenquites fail reads, but not when number of reads comparable to int limit. This change address the issue in two ways, either one is enough, but both are helpful in their own way: H264 parser now fails faster when number of references is too large. BitstreamReader now is resilent to unlimited number of fail reads. Bug: chromium:352402499 Change-Id: I19646bc3f53cd2970393d00bc143400b1fdf5473 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/357100 Commit-Queue: Danil Chapovalov <danilchap@webrtc.org> Reviewed-by: Tomas Gunnarsson <tommi@webrtc.org> Cr-Commit-Position: refs/heads/main@{#42628}
96 lines
3.0 KiB
C++
96 lines
3.0 KiB
C++
/*
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* Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef COMMON_VIDEO_H264_H264_COMMON_H_
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#define COMMON_VIDEO_H264_H264_COMMON_H_
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#include <stddef.h>
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#include <stdint.h>
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#include <vector>
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#include "rtc_base/buffer.h"
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#include "rtc_base/system/rtc_export.h"
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namespace webrtc {
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namespace H264 {
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// The size of a full NALU start sequence {0 0 0 1}, used for the first NALU
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// of an access unit, and for SPS and PPS blocks.
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const size_t kNaluLongStartSequenceSize = 4;
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// The size of a shortened NALU start sequence {0 0 1}, that may be used if
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// not the first NALU of an access unit or an SPS or PPS block.
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const size_t kNaluShortStartSequenceSize = 3;
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// The size of the NALU type byte (1).
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const size_t kNaluTypeSize = 1;
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// Maximum reference index for reference pictures.
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constexpr int kMaxReferenceIndex = 31;
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enum NaluType : uint8_t {
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kSlice = 1,
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kIdr = 5,
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kSei = 6,
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kSps = 7,
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kPps = 8,
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kAud = 9,
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kEndOfSequence = 10,
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kEndOfStream = 11,
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kFiller = 12,
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kPrefix = 14,
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kStapA = 24,
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kFuA = 28
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};
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enum SliceType : uint8_t { kP = 0, kB = 1, kI = 2, kSp = 3, kSi = 4 };
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struct NaluIndex {
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// Start index of NALU, including start sequence.
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size_t start_offset;
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// Start index of NALU payload, typically type header.
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size_t payload_start_offset;
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// Length of NALU payload, in bytes, counting from payload_start_offset.
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size_t payload_size;
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};
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// Returns a vector of the NALU indices in the given buffer.
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RTC_EXPORT std::vector<NaluIndex> FindNaluIndices(const uint8_t* buffer,
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size_t buffer_size);
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// Get the NAL type from the header byte immediately following start sequence.
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RTC_EXPORT NaluType ParseNaluType(uint8_t data);
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// Methods for parsing and writing RBSP. See section 7.4.1 of the H264 spec.
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//
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// The following sequences are illegal, and need to be escaped when encoding:
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// 00 00 00 -> 00 00 03 00
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// 00 00 01 -> 00 00 03 01
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// 00 00 02 -> 00 00 03 02
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// And things in the source that look like the emulation byte pattern (00 00 03)
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// need to have an extra emulation byte added, so it's removed when decoding:
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// 00 00 03 -> 00 00 03 03
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//
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// Decoding is simply a matter of finding any 00 00 03 sequence and removing
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// the 03 emulation byte.
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// Parse the given data and remove any emulation byte escaping.
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std::vector<uint8_t> ParseRbsp(const uint8_t* data, size_t length);
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// Write the given data to the destination buffer, inserting and emulation
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// bytes in order to escape any data the could be interpreted as a start
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// sequence.
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void WriteRbsp(const uint8_t* bytes, size_t length, rtc::Buffer* destination);
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} // namespace H264
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} // namespace webrtc
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#endif // COMMON_VIDEO_H264_H264_COMMON_H_
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