app.py

import gradio as gr
import urllib.request

url = 'http://aust001.pythonanywhere.com/photo/test.avi'
def to_black(text):
    if text=='love':
        urllib.request.urlretrieve(url, 'uu.avi')
        return 'uu.avi'

interface = gr.Interface(fn=to_black, inputs="text", outputs="video")
interface.launch()