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一、读取写入视频文件- 1 import cv2
- 2
- 3 # 创建一个视屏捕获对象
- 4 videoCapture = cv2.VideoCapture('AVI.avi')
- 5
- 6 # 获取视频的属性值,cv2.CAP_PROP_FPS获取视频帧率
- 7 fps = videoCapture.get(cv2.CAP_PROP_FPS)
- 8
- 9 # cv2.CAP_PROP_FRAME_WIDTH/HEIGHT 返回float类型 获取视频帧的宽高
- 10 size = int(videoCapture.get(cv2.CAP_PROP_FRAME_WIDTH)), \
- 11 int(videoCapture.get(cv2.CAP_PROP_FRAME_HEIGHT))
- 12
- 13 '''
- 14 创建一个写入对象,将帧写入输出的视频
- 15 cv2.VideoWriter_fourcc()函数指定编码器为 I420
- 16 fps 和 size 指定输出的帧率和尺寸
- 17 '''
- 18 videoWrite = cv2.VideoWriter('Out.avi',
- 19 cv2.VideoWriter_fourcc('I', '4', '2', '0'),
- 20 fps, size
- 21 )
- 22
- 23 '''
- 24 对捕获到的视频对象进行读取帧,success表示是否成功读取一帧,frame表示当前帧。
- 25 循环读取写入输出视频。
- 26 '''
- 27 success, frame = videoCapture.read()
- 28 while success:
- 29 videoWrite.write(frame)
- 30 success, frame = videoCapture.read()
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二、捕获摄像头帧- 1 import cv2
- 2
- 3 cameraCapture = cv2.VideoCapture(0)
- 4
- 5 fps = 30
- 6
- 7 size = int(cameraCapture.get(cv2.CAP_PROP_FRAME_WIDTH)), \
- 8 int(cameraCapture.get(cv2.CAP_PROP_FRAME_HEIGHT))
- 9
- 10 videoWriter = cv2.VideoWriter(
- 11 'OutVideo_GRAB.avi',
- 12 cv2.VideoWriter_fourcc('I', '4', '2', '0'),
- 13 fps,
- 14 size
- 15 )
- 16
- 17 success, frame = cameraCapture.read()
- 18
- 19 numFramesRemaining = 10 * fps
- 20 while success and numFramesRemaining > 0:
- 21 videoWriter.write(frame)
- 22 success, frame = cameraCapture.read()
- 23 numFramesRemaining -= 1
复制代码 和视频的读取写入没有什么差异,都是需要先创建一个VideoCapture Object来操作,下述是细微差别:
3 Line:VideoCapture(0),其中 0 代表设备,还可以1,2,3 分别代表不同的摄像头(如果存在),也可以输入网络摄像头,直接替换成URL即可
5 Line:需要手动设置fps的值
19 Line:需要设定一个时间,numFramesRemaining代表持续捕获300个帧,而每30个帧为一秒,所以将生成一个10秒钟的视频文件
三、窗口显示图片- 1 import cv2
- 2
- 3 img = cv2.imread('CopyPic.png')
- 4 cv2.imshow('', img)
- 5 cv2.waitKey()
- 6 cv2.destroyAllWindows()
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四、窗口显示摄像头- 1 import cv2
- 2
- 3 # 检测窗口是否被点击
- 4 clicked = False
- 5
- 6
- 7 # 定义鼠标事件处理函数
- 8 def onMouse(event: int, x, y, flags, param):
- 9 global clicked
- 10 if event == cv2.EVENT_LBUTTONUP:
- 11 clicked = True
- 12
- 13
- 14 # 创建一个视频对象
- 15 cameraCapture = cv2.VideoCapture(0)
- 16 # 定义窗口命
- 17 cv2.namedWindow('Camera')
- 18 # 将鼠标回调函数,将鼠标事件处理函数和窗口关联起来
- 19 cv2.setMouseCallback('Camera', onMouse)
- 20
- 21 print('Showing camera feed. Click window or press any key to stop.')
- 22 # 获取当前时间的摄像头帧
- 23 success, frame = cameraCapture.read()
- 24
- 25 # 循环获取当前时间的摄像头帧,当按下任意按键 or 点击鼠标时则停止显示
- 26 while success and cv2.waitKey(1) == -1 and not clicked:
- 27 cv2.imshow('Camera', frame)
- 28 success, frame = cameraCapture.read()
- 29
- 30 # 关闭窗口
- 31 cv2.destroyAllWindows()
- 32
- 33 # 释放摄像头资源
- 34 cameraCapture.release()
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针对多摄像头,我们需要先探明摄像头的设备号:- 1 import cv2
- 2
- 3 for item in range(10):
- 4 # 创建一个object
- 5 camera = cv2.VideoCapture(item)
- 6
- 7 # 查询此摄像头是否能打开,如果不能则跳过,并输出一条 Error Message
- 8 if not camera.isOpened():
- 9 print(f"Can\'t open camera {item}")
- 10 continue
- 11
- 12 # 读取摄像头帧率
- 13 while True:
- 14 success, frame = camera.read()
- 15 # 当摄像头帧读取失败则跳过
- 16 if not success:
- 17 break
- 18
- 19 cv2.imshow(f'Camera device number: {item}', frame)
- 20
- 21 # 等待1毫秒,检查用户是否有键盘输入‘q’
- 22 if cv2.waitKey(1) == ord('q'):
- 23 break
- 24
- 25 camera.release()
- 26 cv2.destroyAllWindows()
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来源:https://www.cnblogs.com/vangoghpeng/p/17847357.html
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