sorting a video on brightness

using FFMPEG to make images from video file
using Python PIL to convert every image to a 1x1 pixel image, and give it a brightness value
sorting the output images by brightness value
copying and renaming the images with SHUTIL
using FFMPEG to make a video from the images

inputFilename: input video
outputFilename: output images (frames)
exportFilename: export video

from PIL import Image
import os, shutil
from argparse import ArgumentParser
from glob import glob


p = ArgumentParser()
p.add_argument("input", help="input filename")
p.add_argument("--inputframerate", type=float, default=1.0, help="frame rate to extract frames (frames per second)")
p.add_argument("--outputframerate", type=float, default=1.0, help="frame rate to extract frames (frames per second)")
p.add_argument("--output", default="output.mp4", help="output filename")
args = p.parse_args()
 
# ***FROM VIDEO TO IMAGE***
# ensure tmp folder
cmd = "mkdir -p tmp"
print (cmd)
os.system(cmd)
cmd = 'ffmpeg -i "{0}" -f image2 -r {1} -an -y tmp/tmp_frame%04d.jpg'
cmd = cmd.format(args.input, args.inputframerate)
print (cmd)
os.system(cmd)

# ***SORTING IMAGES ON BRIGHTNESS (make grayscale, convert to 1x1px image, value the grayscaleness of this pixel) ***
def avg(p):
	pil_im = Image.open(p)
 
	i=pil_im.convert('L')
	i.thumbnail((1,1))
	g=i.getpixel((0,0))
	return g
 
imgs = glob("tmp/tmp_frame*.jpg")    
imgs.sort()
 
d = []
for x in imgs:
	d.append((avg(x), x))
d.sort()
print d
 
i=0
for g, image in d:
	newname='tmp/tmp_sorted{0:04d}.jpg'.format(i)
	print "copying", image , "to", newname
	shutil.copyfile(image, newname)
	i=i+1
 
# ***FROM IMAGES TO VIDEO***
cmd = 'ffmpeg -r {0} -f image2 -i tmp/tmp_sorted%04d.jpg -y "{1}"'
cmd = cmd.format(args.outputframerate, args.output)
print cmd
os.system(cmd)