show_camera_or_video.py

'''
usage:

python show_camera_or_video.py
or
python show_camera_or_video.py cam
or
python show_camera_or_video.py inputfilename.avi
'''
import numpy as np
import cv2

def getSource():
  import sys
  if (len(sys.argv) != 2):
    source = "./xxxx.avi"
  elif (sys.argv[1] == 'cam'):
    source = 0              # 0 means camera_id
  else:
    source = sys.argv[1]
  return source

if __name__=='__main__':
  source = getSource()
  cam = cv2.VideoCapture(source)

  while (True):
    ret, frame = cam.read()
    cv2.imshow('frame', frame)
    if cv2.waitKey(1) & 0xFF == ord('q'):
      break
  cam.release()
  cv2.destroyAllWindows()