Put all files in a directory into list. How?

[Larz60+]

this can be done with pathlib:

I use same path as script file, but you can substitute any path on line 23
note that I removed the '*' from EXTN pathlib wants just the suffix.
I put two files in my src directory, cows.mpeg and trigger.mp4

import pathlib
import os

# This does all the work:
def get_file_list(fpath):
    EXTN = ['.avi', '.flv', '.mkv', '.mov', '.mp4',
        '.mpeg', '.mpg', '.webm', '.wmv']

    if not isinstance(fpath, pathlib.PosixPath):
        fpath = (pathlib.Path(fpath))

    return [filename for filename in fpath.iterdir()
        if filename.is_file() and (filename.suffix in EXTN)]


def main():
    filelist = []

    # anchor starting directory to script path
    os.chdir(os.path.abspath(os.path.dirname(__file__)))

    #create a pathlib path, here it is current path
    fpath = pathlib.Path('.')

    filelist = get_file_list(fpath)

    for filename in filelist:
        print(f"{filename.name}")


if __name__ == '__main__':
    main()

results:

Output:
cows.mpeg
trigger.mp4