OpenCV写文件MP4 flv avi

比眉伴天荒 2022-09-15 05:43 11阅读 0赞

除了ffmpeg写视频外，很多时候我们也采用Opencv写视频文件，官方案例：[入口][Link 1]

其它一些参考文件：  
ffmpeg movflags [参数说明][Link 2]  
[opencv写文件][opencv]  
这里说明一点就是writerAlias->setFourcc(cv::VideoWriter::fourcc(‘X’, ‘2’, ‘6’, ‘4’));编码出来是x264

不过opencv写的视频文件都比较大，暂时没有看到能控制码流的参数，特别avi达到了20Mb/s

下面是一个参考类：

#ifndef FILEWRITER_H
    #define FILEWRITER_H
    
    #include "writer.h"
    
    #include <opencv.hpp>
    
    namespace flow { 
    
    
    class FileWriter { 
    public:
      using FileWriterPtr=std::make_shared<FileWriter>;
      
      explicit FileWriter(const std::string &file) { 
      m_address=file;
      }
      
      FileWriter() = delete;
      FileWriter(FileWriter &&) = delete;
      FileWriter(const FileWriter &) = delete;
      FileWriter &operator=(FileWriter &&) = delete;
      FileWriter &operator=(const FileWriter &) = delete;
      ~FileWriter()  = default;
    
      bool write(const cv::Mat &frame) ;
      void setFourcc(int fourcc) {  m_fourcc = fourcc; }
      static FileWriterPtr create() {  return FileWriterPtr(new FileWriter("./test.avi")); }
      
      bool open() ;
      bool close() ;
    
    protected:
      // use 'int64_t' for memory padding
      int64_t m_fourcc = cv::VideoWriter::fourcc('D', 'I', 'V', 'X');
      cv::Ptr<cv::VideoWriter> m_videoFileWriter;
      std::string m_address{ };
    };
    
    } // namespace flow
    #endif // FILEWRITER_H

#include "filewriter.h"
    
    #include "xlog/xlog.h"
    
    namespace flow { 
    
    bool FileWriter::open() { 
      LOG_INFO("Open file to write: {} ...", m_param.address);
      m_videoFileWriter.reset(new cv::VideoWriter());
      return m_videoFileWriter->open(m_address, static_cast<int>(m_fourcc),
                                     double(25),
                                     cv::Size(2560, 1440));
    }
    
    bool FileWriter::close() { 
      m_videoFileWriter.release();
      return true;
    }
    
    bool FileWriter::write(const cv::Mat &frame) { 
      assert(!m_videoFileWriter.empty());
    
      cv::Mat dst;
      cv::Size size = cv::Size(2560, 1440);
      if (size != frame.mat.size()) { 
        dst = cv::Mat(size, frame.type());
        cv::resize(frame, dst, size);
      } else { 
        dst = frame;
      }
    
      *m_videoFileWriter << dst;
      return true;
    }
    using FileWriterPtr=std::make_shared<FileWriter>;
    } // namespace flow
    
    /main函数/
    //example
    
    void createMat(cv::Mat &mat){ 
    //somewhere cteate mat
    }
    int main(){ 
    FileWriterPtr writerPtr=FileWriter::create("./test.avi");
    writerPtr->setFourcc(cv::VideoWriter::fourcc('X', '2', '6', '4'));//h264 fourcc('D', 'I', 'V', 'X') mpeg
    
    writerPtr.open();
    while(n < 1000){ 
    cv::Mat mat;
    createMat(mat);//somewhere get some mat
    writerPtr.write(mat);
    }
    writerPtr.close();
    }

[Link 1]: https://docs.opencv.org/3.4.8/d4/d26/samples_2cpp_2facedetect_8cpp-example.html
[Link 2]: http://www.bubuko.com/infodetail-2009540.html
[opencv]: https://www.cnblogs.com/sprint1989/p/3804044.html