Python-OpenCV 处理视频（一）： 输入输出
视频的处理和图片的处理类似，只不过视频处理需要连续处理一系列图片。
一般有两种视频源，一种是直接从硬盘加载视频，另一种是获取摄像头视频。
0x00. 本地读取视频
核心函数:
cv.CaptureFromFile()
代码示例：
| 123456789101112131415161718192021222324 | import cv2.cv as cv capture = cv.CaptureFromFile(\’myvideo.avi\’) nbFrames = int(cv.GetCaptureProperty(capture, cv.CV_CAP_PROP_FRAME_COUNT)) #CV_CAP_PROP_FRAME_WIDTH Width of the frames in the video stream#CV_CAP_PROP_FRAME_HEIGHT Height of the frames in the video stream fps = cv.GetCaptureProperty(capture, cv.CV_CAP_PROP_FPS) wait = int(1/fps * 1000/1) duration = (nbFrames * fps) / 1000 print \’Num. Frames = \’, nbFramesprint \’Frame Rate = \’, fps, \’fps\’print \’Duration = \’, duration, \’sec\’ for f in xrange( nbFrames ): frameImg = cv.QueryFrame(capture) print cv.GetCaptureProperty(capture, cv.CV_CAP_PROP_POS_FRAMES) cv.ShowImage(\”The Video\”, frameImg) cv.WaitKey(wait) |
cv2
| 12345678910111213141516 | import numpy as npimport cv2 cap = cv2.VideoCapture(\’vtest.avi\’) while(cap.isOpened()): ret, frame = cap.read() gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY) cv2.imshow(\’frame\’,gray) if cv2.waitKey(1) & 0xFF == ord(\’q\’): break cap.release()cv2.destroyAllWindows() |
0x01. 摄像头视频读取
核心函数：
cv.CaptureFromCAM()
示例代码：
| 12345678910 | import cv2.cv as cv capture = cv.CaptureFromCAM(0) while True: frame = cv.QueryFrame(capture) cv.ShowImage(\”Webcam\”, frame) c = cv.WaitKey(1) if c == 27: #Esc on Windows break |
cv2
| 1234567891011121314151617181920 | import numpy as npimport cv2 cap = cv2.VideoCapture/span>cv2 cap = cv2.VideoCapture=\”crayon-5812a37a11732965027020\” class=\”crayon-syntax crayon-theme-github crayon-font-monaco crayon-os-pc print-yes notranslate\” data-settings=\” minimize scroll-always\” style=\” margin-top: 12px; margin-bottom: 12px; font-size: 13px !important; line-height: 15px !important;\”>
cv2
0x01. 摄像头视频读取核心函数：
示例代码：
cv2
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