A01.py

import sys
import os
from pathlib import Path
import numpy as np
import shutil
import cv2

def load_video_as_frames(video_filepath):
    # Load video
    print("\n\nPROCESS VIDEO: ",video_filepath)
    
    #Use cv2.VideoCapture to load a video from video_filepath
    capture = cv2.VideoCapture(video_filepath)
    
    # Check if data is invalid
    if not capture.isOpened():
        # If the video is not opened, print an error and return None
        print("ERROR: Could not open or find the video!")
        return None
    
    # Loop through the video ONCE and add each frame to a list
    my_frames = []
    
    frame_cnt = int(capture.get(cv2.CAP_PROP_FRAME_COUNT))
    print("video frame count is: ",frame_cnt)
    
    cv2.namedWindow(video_filepath)
    
    for current_frame in range(frame_cnt):
        ret, frame = capture.read()
        #print("on frame: ",current_frame+1)
        #print("shape: ",frame.shape)
        my_frames.append(frame)
    
    #close capture and destroy all windows
    capture.release()
    cv2.destroyAllWindows()
    
    #Return list of frames as numpy array
    return np.array(my_frames)

def compute_wait(fps):
    #Compute the wait in milliseconds as int(1000.0/fps) 
    return int(1000.0/fps)

def display_frames(all_frames, title, fps=30):
    #Call compute_wait(fps) to get the wait time.
    
    wait_time = compute_wait(fps)
    
    #show all the frames
    for frame in all_frames:
        cv2.imshow(title, frame)
        cv2.waitKey(wait_time)
       
    #destroy all windows 
    cv2.destroyAllWindows()

def save_frames(all_frames, output_dir, basename, fps=30):
    #Make the video folder name as basename + “_” + str(fps) 
    video_folder = basename + "_" + str(fps)
    output_path = os.path.join(output_dir, video_folder)
    
    # If the path already exists (os.path.exists()), remove it with shutil.rmtree() 
    if os.path.exists(output_path) is True:
        shutil.rmtree(output_path)
    
    #make the directory
    print("Creating directory",output_path)
    os.makedirs(output_path)
    
    #For each frame...
    for frame in range(len(all_frames)):
        print("frame:",frame)
        #get zero-padded filename
        filename = "image_%07d.png" % frame
        #get full path
        filename = os.path.join(output_path, filename)
        print("filename: ",filename)
        #save frame
        cv2.imwrite(filename,all_frames[frame])

def main(): 
    if len(sys.argv) < 3:
        print("ERROR: Not enough args.")
        exit(1)
    else:
        video_filepath = sys.argv[1]
        output_directory = sys.argv[2]
        core_file_name = Path(video_filepath).stem
        
        #Load all frames; if the function returns None, print an error and exit(1)
        all_frames = load_video_as_frames(video_filepath)
        
        if all_frames is None:
            print("ERROR: Could not get frames.")
            exit(1)
            
        #Display all frames with title “Input Video” and fps of 30
        display_frames(all_frames, "Input Video", fps=30)
        
        # Save the (output) frames to the output folder
        save_frames(all_frames, output_directory, core_file_name, fps=30)

    # Close down...
    print("Closing application...")

if __name__ == "__main__": 
    main()