Python 使用Opencv读写视频（Opencv教程二）

爱被打了一巴掌 2022-05-24 04:59 379阅读 0赞

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读取视频并将视频每帧的图像写入到新的视频文件

import cv2
    vc = cv2.VideoCapture('aa.wmv')
    # 设置每秒传输帧数
    fps = vc.get(cv2.CAP_PROP_FPS)
    # 获取视频的大小
    size = (int(vc.get(cv2.CAP_PROP_FRAME_WIDTH)),int(vc.get(cv2.CAP_PROP_FRAME_HEIGHT)))
    # 生成一个空的视频文件
    # 视频编码类型
    # cv2.VideoWriter_fourcc('X','V','I','D') MPEG-4 编码类型
    # cv2.VideoWriter_fourcc('I','4','2','0') YUY编码类型
    # cv2.VideoWriter_fourcc('P','I','M','I') MPEG-1 编码类型
    # cv2.VideoWriter_fourcc('T','H','E','O') Ogg Vorbis类型，文件名为.ogv
    # cv2.VideoWriter_fourcc('F','L','V','1') Flask视频，文件名为.flv
    vw = cv2.VideoWriter('mya.avi',cv2.VideoWriter_fourcc('X','V','I','D'), fps, size)
    # 读取视频第一帧的内容
    success, frame = vc.read()
    while success:
        # frame = cv2.flip(frame, 2) # 反转视频画面
        # 写入视频
        vw.write(frame)
        # 读取视频下一帧的内容
        success, frame = vc.read()
    print('a')

开启摄像头并捕捉摄像头10秒的视频信息

import cv2
    # 获取摄像头
    cameraCapture = cv2.VideoCapture(0)
    # 设置每秒传输帧数
    fps = 30
    size = (int(cameraCapture.get(cv2.CAP_PROP_FRAME_WIDTH)),int(cameraCapture.get(cv2.CAP_PROP_FRAME_HEIGHT)))
    # 设置视频文件格式
    vw = cv2.VideoWriter('camera.avi',cv2.VideoWriter_fourcc('I','4','2','0'), fps, size)
    # 读取摄像头的图像，函数 isOpened 判断摄像头是否开启，返回布尔型
    if cameraCapture.isOpened():
        success, frame = cameraCapture.read()
        # # 若有多个摄像头，可使用
        # success = cameraCapture.grab()
        # success, frame = cameraCapture.retrieve()
    # 10 代表10秒，1个fps代表1秒
    num = 10 * fps
    while success and num>0:
    	# 显示摄像头录制窗口
    	# cv2.imshow('MyPic',frame)
        # cv2.waitKey(1)
        # 写入图像到视频文件
        vw.write(frame)
        # 读取摄像头的图像
        success, frame = cameraCapture.read()
        # # 若有多个摄像头，可使用
        # success = cameraCapture.grab()
        # success, frame = cameraCapture.retrieve()
        num -= 1
    # 释放摄像头
    cameraCapture.release()
    # 注销录制窗口
    # cv2.destroyWindow('MyPic')

显示摄像头

import cv2
    clicked = False
    # onMouse是回调函数。
    def onMouse(event, x, y, flags, param):
        global clicked
        # 松开鼠标左键所触发的事件
        if event == cv2.EVENT_LBUTTONUP:
            clicked = True
    cameraCapture = cv2.VideoCapture(0)
    # 创建MyWindow窗口
    cv2.namedWindow('MyWindow')
    # 设置MyWindow窗口的鼠标回滚
    cv2.setMouseCallback('MyWindow', onMouse)
    success, frame = cameraCapture.read()
    while success and cv2.waitKey(1) == -1 and not clicked:
        # 将图片显示在MyWindow窗口
        cv2.imshow('MyWindow', frame)
        success, frame = cameraCapture.read()
    # 注销MyWindow窗口
    cv2.destroyWindow('MyWindow')
    # 释放摄像头
    cameraCapture.release()

函数setMouseCallback的触发的事件如下：  
![这里写图片描述][70]

参考资料：OpenCV 3计算机视觉 Python语言实现第二版

[70]: /images/20220524/6b7d8caa898549cb9992e6911daeb4ce.png