import cv2

import numpy as np

cap = cv2.VideoCapture("D:/Workspace/week2/test/test_256_12.mp4")

ret, frame1 = cap.read()

prvs = cv2.cvtColor(frame1,cv2.COLOR_BGR2GRAY)

hsv = np.zeros_like(frame1)

hsv[...,1] = 255

num = 1

while(1):

    ret, frame2 = cap.read()

    next = cv2.cvtColor(frame2,cv2.COLOR_BGR2GRAY)

    flow = cv2.calcOpticalFlowFarneback(prvs,next, None, 0.5, 3, 6, 3, 5, 1.25, 0)

    mag, ang = cv2.cartToPolar(flow[...,0], flow[...,1])

    hsv[...,0] = ang*180/np.pi/2

    hsv[...,2] = cv2.normalize(mag,None,0,255,cv2.NORM_MINMAX)

    rgb = cv2.cvtColor(hsv,cv2.COLOR_HSV2BGR)

    cv2.imshow("frame",frame2)

    cv2.imshow("flow",rgb)

    k = cv2.waitKey(30) & 0xff

    if k == 27:

        break

    elif k == ord('s'):

        cv2.imwrite('opticalfb.png',frame2)

        cv2.imwrite('opticalhsv.png',rgb)

    prvs = next

cap.release()

cv2.destroyAllWindows()