Get the video count and size in GB of a internet archive item which contains mp4s. ia (https://github.com/jjjake/internetarchive) must be installed.

ia-youtube-archive-get-size.py

import subprocess
import io

out = subprocess.check_output("ia list " + input() + " -c size -g *.mp4", shell=True)
string = io.StringIO(out.decode("utf-8"))
count = 0
total_bytes = 0

for line in string:
    count += 1
    total_bytes += int(line)

print(str(count) + " videos")
print(str(total_bytes / 1000000000) + " GB")