Download from youtube

[snippsat]

Also missing .format.
Need raw string in path r"C:\Users\Anton"

url = 'http://google.com'
process_call = 'ffmpeg -ss {1} -to {2} -i "{0}" -acodec aac -b:a 192k -avoid_negative_ts make_zero "{3}"'.\
format(url, "00:10:00.00", "00:10:56.00", r"C:\Users\Anton")
print(repr(process_call))

Output:
'ffmpeg -ss 00:10:00.00 -to 00:10:56.00 -i "http://google.com" -acodec aac -b:a 192k -avoid_negative_ts make_zero "C:\\Users\\Anton"'

Advice is always write it as list to avoid shell=True(not secure).