OpenCV-002：从本地摄像头读取视频并播放

#https://opencv-python-tutroals.readthedocs.io/en/latest/py_tutorials/py_gui/py_video_display/py_video_display.html#display-video
###########################################
####Import Module                      ####
import cv2
import numpy as np
###########################################
####Global Parameter                   ####
G_VideoCapFrom0 = cv2.VideoCapture(0)
###########################################
####Sub Function                       ####
def F_CaptureFromCamera0UntilPressQ():
    while(1):
        # get a frame
        ret, frame = G_VideoCapFrom0.read()
        if ret==True:
            # Our operations on the frame
            gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
            # show a frame
            cv2.imshow("captureColor", frame)
            cv2.imshow("captureGray", gray)
            if cv2.waitKey(1) & 0xFF == ord('q'):
                break
        else:
            print("Can not open camera")
            break
###########################################
####Main Function                      ####  
F_CaptureFromCamera0UntilPressQ()          
G_VideoCapFrom0.release()
cv2.destroyAllWindows()