DisplayFrames.py

#!/usr/bin/env python3

import cv2
import time

# globals
outputDir    = 'frames'
frameDelay   = 42       # the answer to everything

# initialize frame count
count = 0

startTime = time.time()

# Generate the filename for the first frame 
frameFileName = "{}/grayscale_{:04d}.jpg".format(outputDir, count)

# load the frame
frame = cv2.imread(frameFileName)

while frame is not None:
    
    print("Displaying frame {}".format(count))
    # Display the frame in a window called "Video"
    cv2.imshow("Video", frame)

    # compute the amount of time that has elapsed
    # while the frame was processed
    elapsedTime = int((time.time() - startTime) * 1000)
    print("Time to process frame {} ms".format(elapsedTime))
    
    # determine the amount of time to wait, also
    # make sure we don't go into negative time
    timeToWait = max(1, frameDelay - elapsedTime)

    # Wait for 42 ms and check if the user wants to quit
    if cv2.waitKey(timeToWait) and 0xFF == ord("q"):
        break    

    # get the start time for processing the next frame
    startTime = time.time()
    
    # get the next frame filename
    count += 1
    frameFileName = "{}/grayscale_{:04d}.jpg".format(outputDir, count)

    # Read the next frame file
    frame = cv2.imread(frameFileName)

# make sure we cleanup the windows, otherwise we might end up with a mess
cv2.destroyAllWindows()