mirror of
https://github.com/ZLMediaKit/ZLMediaKit.git
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98 lines
3.0 KiB
C++
98 lines
3.0 KiB
C++
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/*
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* Copyright (c) 2016-present The ZLMediaKit project authors. All Rights Reserved.
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*
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* This file is part of ZLMediaKit(https://github.com/ZLMediaKit/ZLMediaKit).
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*
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* Use of this source code is governed by MIT-like license that can be found in the
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* LICENSE file in the root of the source tree. All contributing project authors
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* may be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef ZLMEDIAKIT_MP2V_H
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#define ZLMEDIAKIT_MP2V_H
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#include "Extension/Frame.h"
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#include "Extension/Track.h"
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namespace mediakit {
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/**
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* MPEG-2 Video 帧辅助类模板
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* MPEG-2 Video frame helper class template
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*/
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template <typename Parent>
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class MP2VFrameHelper : public Parent {
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public:
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using Ptr = std::shared_ptr<MP2VFrameHelper>;
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template <typename... ARGS>
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MP2VFrameHelper(ARGS &&...args)
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: Parent(std::forward<ARGS>(args)...) {
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this->_codec_id = CodecMP2V;
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}
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/**
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* MPEG-2 视频起始码: 00 00 01 00 (picture_start_code)
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* I帧判断：picture_coding_type == 1 (I-Picture)
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* picture_coding_type 位于 picture header 的第 11-12 bit (从 temporal_reference 之后)
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*
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* MPEG-2 video start code: 00 00 01 00 (picture_start_code)
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* I-frame detection: picture_coding_type == 1 (I-Picture)
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*/
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bool keyFrame() const override {
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auto data = (const uint8_t *)this->data() + this->prefixSize();
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auto size = this->size() - this->prefixSize();
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return isMP2VKeyFrame(data, size);
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}
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bool configFrame() const override { return false; }
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static bool isMP2VKeyFrame(const uint8_t *data, size_t size) {
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// 查找 picture start code (00 00 01 00)，然后检查 picture_coding_type
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// Look for picture start code (00 00 01 00), then check picture_coding_type
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for (size_t i = 0; i + 5 < size; ++i) {
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if (data[i] == 0x00 && data[i + 1] == 0x00 && data[i + 2] == 0x01 && data[i + 3] == 0x00) {
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// picture header: temporal_reference(10bits) + picture_coding_type(3bits)
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// picture_coding_type: 001 = I, 010 = P, 011 = B
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uint8_t picture_coding_type = (data[i + 5] >> 3) & 0x07;
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return picture_coding_type == 1;
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}
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}
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return false;
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}
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};
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/// MPEG-2 Video 帧类
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using MP2VFrame = MP2VFrameHelper<FrameImp>;
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using MP2VFrameNoCacheAble = MP2VFrameHelper<FrameFromPtr>;
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/**
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* MPEG-2 Video Track
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*/
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class MP2VTrack : public VideoTrackImp {
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public:
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using Ptr = std::shared_ptr<MP2VTrack>;
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MP2VTrack() : VideoTrackImp(CodecMP2V) {}
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Track::Ptr clone() const override { return std::make_shared<MP2VTrack>(*this); }
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bool inputFrame(const Frame::Ptr &frame) override;
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private:
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Sdp::Ptr getSdp(uint8_t payload_type) const override;
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/**
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* 从 sequence header 中解析宽高和帧率
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* Parse width, height and fps from sequence header
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*/
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void parseSequenceHeader(const uint8_t *data, size_t size);
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private:
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bool _seq_header_parsed = false;
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};
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} // namespace mediakit
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#endif // ZLMEDIAKIT_MP2V_H
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