opencv-012-视频读写

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知识点

VideoCapture 视频文件读取、摄像头读取、视频流读取
VideoWriter 视频写出、文件保存、

  • CAP_PROP_FRAME_HEIGHT #高度
  • CAP_PROP_FRAME_WIDTH #宽度
  • CAP_PROP_FRAME_COUNT #数量
  • CAP_PROP_FPS #帧率

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。

代码（c++,python）

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#include <iostream>
#include <opencv2/opencv.hpp>

using namespace std;
using namespace cv;

/*
 * 视频读写
 */
int main() {
    // 打开摄像头
    // VideoCapture capture(0);
    // 打开视频文件
    VideoCapture capture;
    capture.open("../images/vtest.avi");
    if (!capture.isOpened()) {
        cout << "could not load video.." << endl;
        return -1;
    }

    Size S = Size((int) capture.get(CAP_PROP_FRAME_WIDTH), (int) capture.get(CAP_PROP_FRAME_HEIGHT));
    int fps = capture.get(CAP_PROP_FPS);
    cout << "capture fps: " << fps << endl;
    VideoWriter writer("D:/test.mp4", cv::VideoWriter::fourcc('D', 'I','V','X'), fps, S, true);

    Mat frame;
    while(capture.read(frame)){
        imshow("input", frame);
        writer.write(frame);
        char c = waitKey(50);
        if(c == 27){
            break;
        }
    }
    capture.release();
    writer.release();

    waitKey(0);
    return 0;
}
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import cv2 as cv
import numpy as np


capture = cv.VideoCapture("D:/vcprojects/images/768x576.avi")
# capture = cv.VideoCapture(0) 打开摄像头
height = capture.get(cv.CAP_PROP_FRAME_HEIGHT)
width = capture.get(cv.CAP_PROP_FRAME_WIDTH)
count = capture.get(cv.CAP_PROP_FRAME_COUNT)
fps = capture.get(cv.CAP_PROP_FPS)
print(height, width, count, fps)
out = cv.VideoWriter("D:/test.mp4", cv.VideoWriter_fourcc('D', 'I', 'V', 'X'), 15,
                     (np.int(width), np.int(height)), True)
while True:
    ret, frame = capture.read()
    if ret is True:
        cv.imshow("video-input", frame)
        out.write(frame)
        c = cv.waitKey(50)
        if c == 27: # ESC
            break
    else:
        break

capture.release()
out.release()

结果

代码地址

github