This loops a videofile and shows the time on top.

opencvvideoclock.py

# To simulate netcat: https://gist.github.com/leonjza/f35a7252babdf77c8421
# Test Cython for dithering: http://docs.cython.org/en/latest/src/tutorial/numpy.html
import numpy as np
from time import localtime, strftime, time, sleep
import cv2
import sys

use_cython = True

if use_cython:
    import pyximport
    pyximport.install(setup_args={"include_dirs":np.get_include()}, reload_support=True)
    import st_dither2 as st_dither
else:
    import st_dither

def gen_bayer_matrix(n, old=None, brightness=0):
    if old is None:
        old = np.array([[1, 2], [3, 0]],dtype=np.float)

    if len(old) >= n:
        for y in range(len(old)):
            for x in range(len(old)):
                old[x, y] = 255 * ((old[x, y] + 0.5) / (len(old) * len(old)))
        return old

    new = np.zeros((len(old) * 2, len(old) * 2),dtype=np.float)
    for i in range(4):
        new[len(old) * (i % 2):len(old) + (len(old) * (i % 2)), len(old) * (i // 2):len(old) + (len(old) * (i // 2))] = ((4 * old + (i + 1) % 4)-brightness)

    return gen_bayer_matrix(n, old=new)

  
def rotate_bound(image, angle):
    # grab the dimensions of the image and then determine the
    # center
    (h, w) = image.shape[:2]
    (cX, cY) = (w // 2, h // 2)
 
    # grab the rotation matrix (applying the negative of the
    # angle to rotate clockwise), then grab the sine and cosine
    # (i.e., the rotation components of the matrix)
    M = cv2.getRotationMatrix2D((cX, cY), -angle, 1.0)
    cos = np.abs(M[0, 0])
    sin = np.abs(M[0, 1])
 
    # compute the new bounding dimensions of the image
    nW = int((h * sin) + (w * cos))
    nH = int((h * cos) + (w * sin))
 
    # adjust the rotation matrix to take into account translation
    M[0, 2] += (nW / 2) - cX
    M[1, 2] += (nH / 2) - cY
 
    # perform the actual rotation and return the image
    return cv2.warpAffine(image, M, (nW, nH))
  
def main():    
    bayer_size = 64
    brightness = 0.1
    th_map = gen_bayer_matrix(bayer_size, None, brightness)
    # print(th_map)
    OutError = None
    cap = cv2.VideoCapture(r"C:\Users\Stefan\Pictures\20160630_154705.avi")
    font = cv2.FONT_HERSHEY_SIMPLEX   
    outfilepath = r"C:\Users\Stefan\PycharmProjects\OpenCVTest\outfile.gmv"
    outfile = open(outfilepath, "wb")

    while cap.isOpened():
        ret, frame = cap.read()
        # Loop back to the start of the video and the loop
        if not ret:
            cap.set(cv2.CAP_PROP_POS_MSEC, 0)
            # print("Reset")
            continue
        
        gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
        
        # We want the picture in portrait-orientation
        (height, width) = gray.shape[:2]
        if width > height:
            gray = rotate_bound(gray,90)
        # And it should be 600x800
        if (height, width) != (800, 600):
            gray = cv2.resize(gray,(600,800))
            
        currclocktime = strftime("%X", localtime())
        textdims = cv2.getTextSize(currclocktime, font, 4, 2)
        textcoords = (int((gray.shape[:2][1]-textdims[0][0])/2), int((gray.shape[:2][0]-textdims[0][1])/4))      
        cv2.putText(gray, currclocktime, textcoords, font, 4, (255, 255, 255), 2, cv2.LINE_AA)
        
        lastframetime = time()
        
        gray = st_dither.apply_ordered_dither(gray, th_map, bayer_size)
        
        # print(time()-lastframetime)
        
        #cv2.imshow('frame', gray)
        #if cv2.waitKey(1) & 0xFF == ord('q'):
        #    break
        #if (time()-lastframetime) < (1/7.7):
        #    sleep((1/7.7)-(time()-lastframetime))
        # Pack and save the resulting frames
        
        outarray = gray.reshape(-1,8)
        outarray = np.fliplr(outarray)  
        outarray = outarray * 255
        outarray = np.packbits(outarray,None)
        #outarray.tofile(outfile)
        
        for i in outarray:
            sys.stdout.buffer.write(i)
        # This does not work with stdout
        # outarray.tofile(sys.stdout)

    cap.release()
    cv2.destroyAllWindows()
    outfile.close()

if __name__ == "__main__":
    main()