A videoplayer able to play back gmv and gzipped gmv files

gmvplayer.py

import numpy as np
import cv2
import gzip
import sys, os
from time import sleep, time


def main():
    width = 600
    height = 800
    if len(sys.argv) > 1:
        filepath = sys.argv[1]
    else:
        filepath = os.path.join(os.getcwd(),'gmvid.gmv')
    print(filepath)
    if filepath != "stdin":
        if filepath.endswith(".gz"):
            inputfile = gzip.open(filepath, "rb")
        else:
            inputfile = open(filepath, "rb")
    else:
        inputfile = sys.stdin.buffer
    
    while True:
        lastframetime = time()
        singleframe = inputfile.read(int((width*height)/8))
        if not singleframe:
            break
        nparr = np.frombuffer(singleframe,np.uint8)
        
        nparr = np.unpackbits(nparr)
        
        nparr = nparr.reshape(-1,8)
        nparr = np.fliplr(nparr)  
        nparr = nparr * 255
        
        try:
            nparr = np.fromstring(nparr,dtype=np.uint8).reshape(height,width,1)    
        except ValueError:
            pass
        cv2.imshow("image",nparr)
        if cv2.waitKey(1) & 0xFF == ord('q'):
                break
        if (time()-lastframetime) < (1/7.7):
            sleep((1/7.7)-(time()-lastframetime))
        print(1.0/(time()-lastframetime))
    cv2.destroyAllWindows()
    inputfile.close()
    
if __name__ == "__main__":
    main()