视频转化为图片或灰度视频

1.视频转化为图片

import cv2video_path=r"D:\Dataset\video/7.mp4"
capture=cv2.VideoCapture(video_path)
# print(capture.get(5))if capture.isOpened():ret,img=capture.read()index=0while ret:if index%20==0:imgid=r"D:\Dataset\image/6/"+"%07d"%index+".jpg"print(index,ret)cv2.imwrite(imgid,img)ret,img=capture.read()index=index+1
capture.release()

2.视频转化为灰度视频

import cv2
'''
这是一个将彩色视频装换成灰度视频的代码块
'''
cap = cv2.VideoCapture(r'D:\Dataset/video/1.mp4')fourcc = cv2.VideoWriter_fourcc('m', 'p', '4', 'v')
out = cv2.VideoWriter(r'D:\Dataset\video/1-1.mp4',fourcc, 30.0, (720,1280),False)while(cap.isOpened()):ret, frame = cap.read()if ret==True:frame = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)out.write(frame)cv2.imshow('frame',frame)if cv2.waitKey(1) & 0xFF == ord('q'):breakelse:break
cap.release()
out.release()
cv2.destroyAllWindows()

3.图片转化为视频

import numpy as np
import cv2
size = (432,288)#这个是图片的尺寸，一定要和要用的图片size一致
#完成写入对象的创建，第一个参数是合成之后的视频的名称，第二个参数是可以使用的编码器，第三个参数是帧率即每秒钟展示多少张图片，第四个参数是图片大小信息
videowrite = cv2.VideoWriter(r'F:\test.mp4',-1,20,size)#20是帧数，size是图片尺寸
img_array=[]
for filename in [r'F:\Picture\{0}.jpg'.format(i) for i in range(100000)]:#这个循环是为了读取所有要用的图片文件img = cv2.imread(filename)if img is None:print(filename + " is error!")continueimg_array.append(img)
for i in range(100000):#把读取的图片文件写进去videowrite.write(img_array[i])
videowrite.release()
print('end!')

4.打开摄像头

import cv2
import numpy as np
def video_demo():capture = cv2.VideoCapture(0,cv2.CAP_DSHOW)#0为电脑内置摄像头while(True):ret, frame = capture.read()#摄像头读取,ret为是否成功打开摄像头,true,false。 frame为视频的每一帧图像frame = cv2.flip(frame, 1)#摄像头是和人对立的，将图像左右调换回来正常显示。cv2.imshow("video", frame)c = cv2.waitKey(50)if c == 27:break
video_demo()
cv2.destroyAllWindows()