JPEG degradation

app.py

#!/usr/bin/env python3

# setup
# sudo apt install libmagickwand-dev ffmpeg
# pip3 install Wand progressbar
# ffmpeg -framerate 30 -i out/%05d.jpg -c:v libx264 -r 30 jpeg.mp4
from random import randrange

from wand.image import Image
import progressbar

last_name = 'src0.jpg'
for i in progressbar.progressbar(range(300)):
    with Image(filename=last_name) as img:
        last_name = 'out/%05d.jpg' % i
        with img.clone() as im:
            im.compression = 'jpeg'
            im.compression_quality = randrange(10, 70)
            im.save(filename=last_name)