does not work on windows

it does not work on windows, even though i added windows binaries in the same folder, downloaded the mpd manifest and fed it like this:
```
python ./web-dl.py -u D:/coding/python/web-dl/manifest-mpd.mpd -o test.mkv
```
if you want the specific manifest for testing, dm me on discord kraxen72

the error is:

but i think it's due to the script calling linux-only commands that it doesen't work

Start with web-dl.py and reproduce the reported command using a Windows environment and the supplied MPD manifest. Identify which part of the run fails on Windows, then verify that the same command produces test.mkv without relying on Linux-only behavior.

Written by the indexing model from the issue text.