Youtube to GIF [Python]

ygif.py

# Youtube to GIF Converter
# (with youtube-dl and ffmpeg)
# made by Paulo Elienay II
# at paulo [at] pauloelienay.com

# imports
import sys, os

# vars
# default vars
output_name = "o.gif" # very self explanatory
output_ext = "mp4" # for a *really* better quality, change this to webm
output_name2 = "o." + output_ext # very self explanatory
path = "~/Videos/gifs/" # very self explanatory
fps = 16 # 16 frames per second
duration = 5 # 5 seconds
url = "https://www.youtube.com/watch?v=dQw4w9WgXcQ" # Rick Roll
start = 0 # default value
size = 430 # default value

# defs
def clear(): os.system('clear')
def check(user, default):
    if user == "":
        return default
    if not user == "":
        return user
def change_fps(): # can work
    if len(sys.argv) > 1:
        fps = int(sys.argv[1])

# first / hello screen
clear()
print ("Youtube to GIF")
print ("You can change the fps with 'python3 ygif.py X'")
print ("Change quality and path editing the file")
print ("Press [Enter] for default")

# getting the vars from the user
print ("")
user_url = input("URL link: ")
url = check(user_url, url)
user_start = input("Start (seconds) [default: 0s]: ")
start = check(user_start, start)
user_duration = input("Duration (seconds) [default: 5s]: ")
duration = check(user_duration, duration)
user_name = input("GIF name: ")
output_name = check(user_name, output_name) + ".gif"

# using youtube-dl to download the video
clear()
print ('Downloading the video... (1/2)')
os.system(f'youtube-dl -f "{output_ext}" -o {output_name2} {url}')

# using ffmpeg to convert the video file
clear()
print ('Converting the video... (2/2)')
output_name = path + output_name # adding path to .gif output
os.system(f'ffmpeg -loglevel warning -ss {start} -t {duration} -y -i {output_name2} -vf "fps={fps},scale={size}:-1:flags=lanczos,palettegen" palette.png') # ffmpeg magic
os.system(f'ffmpeg -loglevel warning -ss {start} -t {duration} -y -i {output_name2} -i palette.png -filter_complex "fps={fps},scale={size}:-1:flags=lanczos[x];[x][1:v]paletteuse" {output_name}') # ffmpeg magic
# removing temp files
os.system('rm palette.png')
os.system(f'rm {output_name2}')

# final screen
clear()
print(f"Your GIF was saved in {output_name}")