OpenCV---视频操作

用摄像头捕获视频

import cv2 as cv
import numpy
cap = cv.VideoCapture(0)
while(cap.isOpened()):
    ret, frame = cap.read()  # read()   它返回两个值，第一个是布尔值，表示是否成功读取到一帧，第二个是帧本身。
    cv.imshow('Video', frame)
    if cv.waitKey(25) & 0xFF == ord('q'):
        cap.release()
        break
cv.destroyAllWindows()
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没有摄像头，我们可以使用一款APPIP摄像头
cap = cv.VideoCapture(0) 0改成IP摄像头内容中的局域网IP

从文件中播放视频

import cv2 as cv
myVC = cv2.VideoCapture('../video.mp4')      # 设置窗口宽高 myVC.set(3, 160)  myVC.set(4,120)
while True:
    check, frame = myVC.read()
    cv2.imshow('Camera', frame)
    if(cv2.waitKey(1) == ord('q')):
        myVC.release()
        break
cv2.destroyAllWindows()

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保存视频

import cv2 as cv
import numpy as np

myVC = cv.VideoCapture(0)
fourcc = cv.VideoWriter_fourcc(*'XVID')
out = cv.VideoWriter('output.avi', fourcc, 20.0, (640,480))

while(myVC.isOpened()):
    ret, frame = myVC.read()    # 读操作
    if ret == True:
        frame = cv.flip(frame, 0)   # flip() 用于沿Y轴翻转视频的1图像
        out.write(frame)        # 写操作
        cv.imshow('Camera', frame)  # 展示效果：在哪个窗口，哪一帧图像
        if cv.waitKey(1) & 0xFF == ord('q'):
            break
    else:
        break
myVC.release()
out.release()
cv.destroyAllWindows()

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