Day and Night Time Lapse with RaspberryPI

#!/usr/local/bin/python3

import cv2
import argparse
import os
import functools
from functools import cmp_to_key

def help ():
 with open(__file__, "r", encoding="UTF-8") as open_file:
  for line in open_file:
   if ":" in line and "def" in line and "if " not in line:
    print(line.split(" ")[1])

#Function to check if string can be cast to int
def isnum (num):
 try:
  int(num)
  return True
 except:
  return False

#Numerically sorts filenames
def image_sort_name (x,y):
 
 x = int(x.split(".")[0])
 y = int(y.split(".")[0])
 return x-y

#Sort filenames by their last edited datetime stamp
#This way, even if you didn't name and number your frames, you can still use their order of creation for sorting
#10/10! :)
def image_sort_datetime (x,y):
 x = os.path.getmtime(x)
 y = os.path.getmtime(y)
 return x - y

def render ():
 # Construct the argument parser and parse the arguments
 arg_parser = argparse.ArgumentParser()
 arg_parser.add_argument("-e", "--extension", required=False, default='png', help="Extension name. default is 'png'.")
 arg_parser.add_argument("-o", "--output", required=False, default='output.mp4', help="Output video file.")
 arg_parser.add_argument("-d", "--directory", required=False, default='.', help="Specify image directory.")
 arg_parser.add_argument("-fps", "--framerate", required=False, default='10', help="Set the video framerate.")
 arg_parser.add_argument("-s", "--sort", required=False, default='numeric', help="Determines the type of file-order sort that will be used. Current values: none, numeric, datetime")
 arg_parser.add_argument("-t", "--time", required=False, default='none', help="Sets the framerate so that the video length matches the time in seconds.")
 arg_parser.add_argument("-v", "--visual", required=False, default='false', help="If 'true' then will display preview window.")
 arg_parser.add_argument("-safe", "--safe", required=False, default='true', help="If 'false' then will try to render all images, not just consistenly-sized ones.")
 args = vars(arg_parser.parse_args())

 # Arguments
 dir_path = args['directory']
 ext = args['extension']
 output = args['output']
 framerate = args['framerate']
 sort_type = args['sort']
 time = args['time']
 visual = args['visual']

 #Flips bools to a bool-type
 visual = visual == "true"
 safe = args['safe'] == "true"

 #Sets the framerate to argument, or defaults to 10
 if not isnum(framerate):
  framerate = 10
 else:
  framerate = int(framerate)

 #Get the files from directory
 images = []
 for f in os.listdir(dir_path):
  if f.endswith(ext):
   images.append(f)

 #Sort the files found in the directory
 if sort_type == "numeric":
  int_name = images[0].split(".")[0]
  if isnum(int_name):
   images = sorted(images, key=cmp_to_key(image_sort_name))
  else:
   print("Failed to sort numerically, switching to alphabetic sort")
   images.sort()
 elif sort_type == "datetime":
  images = [dir_path + "/" + im for im in images]
  images = sorted(images, key=cmp_to_key(image_sort_datetime))
  images = ["".join(im.split(dir_path + "/")[1:]) for im in images]
 elif sort_type == "alphabetic":
  images.sort()

 #Change framerate to fit the time in seconds if a time has been specified.
 #Overrides the -fps arg
 if isnum(time):
  framerate = int(len(images) / int(time))
  print("Adjusting framerate to " + str(framerate))

 # Determine the width and height from the first image
 image_path = os.path.join(dir_path, images[0])
 frame = cv2.imread(image_path)

 if visual:
  cv2.imshow('video',frame)
 regular_size = os.path.getsize(image_path)
 height, width, channels = frame.shape

 # Define the codec and create VideoWriter object
 fourcc = cv2.VideoWriter_fourcc(*'mp4v') # Be sure to use lower case
 out = cv2.VideoWriter(output, fourcc, framerate, (width, height))

 for n, image in enumerate(images):
  image_path = os.path.join(dir_path, image)
  image_size = os.path.getsize(image_path)
  if image_size < regular_size / 1.5 and safe:
   print("Cancelled: " + image)
   print("Abnormal image size. Use the '-safe false' to disable this check")
   continue

  frame = cv2.imread(image_path)
  out.write(frame) # Write out frame to video
  if visual:
   cv2.imshow('video', frame)

  if (cv2.waitKey(1) & 0xFF) == ord('q'): # Hit `q` to exit
   break
  if n%100 == 0:
   print("Frame " + str(n))

 # Release everything if job is finished
 out.release()
 cv2.destroyAllWindows()

 print("The output video is {}".format(output))
render()