OpenCV4.0入门（12）视频读写

知识点：

1、VideoCapture 视频文件读取、摄像头读取、视频流读取
2、获取视频的相关属性
- CAP_PROP_FRAME_HEIGHT // 高
- CAP_PROP_FRAME_WIDTH // 宽
- CAP_PROP_FRAME_COUNT // 总帧数
- CAP_PROP_FPS // 帧率
3、VideoWriter 视频写出、文件保存

注意事项：

OpenCV 不支持音频编码与解码保存，不是一个音视频处理的库！主要是分析与解析视频内容。保存文件最大支持单个文件为2G。

C++代码

#include <opencv2/opencv.hpp>
#include <iostream>
using namespace std;
using namespace cv;
void day12() {
    VideoCapture capture;
    // 打开本地的视频文件
    //capture.open("G:\\opencvTest\\video.mp4");
    // 打开摄像头，0是电脑自带的摄像头，序号依次递增为外接摄像头
    capture.open(1);
    if (!capture.isOpened()) {
        cout << "could not open this capture.." << endl;
    }
    int width = static_cast<int>(capture.get(CAP_PROP_FRAME_WIDTH));
    int height = static_cast<int>(capture.get(CAP_PROP_FRAME_HEIGHT));
    int count = static_cast<int>(capture.get(CAP_PROP_FRAME_COUNT));
    int fps = static_cast<int>(capture.get(CAP_PROP_FPS));
    cout << "分辨率：(" << width << "x" << height << ") " << endl;
    cout << "总帧数：" << count << endl;
    cout << "帧率：" << fps << endl;
    int type = static_cast<int>(capture.get(CAP_PROP_FOURCC));
    VideoWriter writer("G:\\opencvTest\\video.mp4", type, fps, Size(width, height), true);
    Mat frame;
    while (capture.read(frame)) {
        imshow("capture_video", frame);
        writer.write(frame);
        // 监听键盘事件，按Esc退出
        char c = waitKey(50);
        if (c == 27) {
            break;
        }
    }
    // 释放资源
    writer.release();
    capture.release();
}

Python代码

Javascript代码