import cv2 as cv
import numpy as np
cap = cv.VideoCapture("./vid/zootopia.mkv")
ret, frame1 = cap.read()
prvs = cv.cvtColor(frame1,cv.COLOR_BGR2GRAY)
hsv = np.zeros_like(frame1)
hsv[...,1] = 255
print("read")
cap.set(cv.CAP_PROP_POS_FRAMES,59760)
print("read done")
while(1):
    for i in range(1,12):
        cap.read()
    ret, frame2 = cap.read()
    next = cv.cvtColor(frame2,cv.COLOR_BGR2GRAY)
    flow = cv.calcOpticalFlowFarneback(prvs,next, None, 0.5, 3, 15, 3, 5, 1.2, 0)
    mag, ang = cv.cartToPolar(flow[...,0], flow[...,1])
    hsv[...,0] = ang*180/np.pi/2
    hsv[...,2] = cv.normalize(mag,None,0,255,cv.NORM_MINMAX)
    bgr = cv.cvtColor(hsv,cv.COLOR_HSV2BGR)
    cv.namedWindow("frame2", cv.WINDOW_NORMAL)
    cv.namedWindow("frame", cv.WINDOW_NORMAL)
    cv.imshow('frame2',bgr)
    cv.imshow("frame",frame2)
    cv.waitKey(1)
    #k = cv.waitKey(0.1) & 0xff
    #if k == 27:
    #    break
    #elif k == ord('s'):
    #    cv.imwrite('opticalfb.png',frame2)
    #    cv.imwrite('opticalhsv.png',bgr)
    prvs = next
cap.release()
cv.destroyAllWindows()