Not working yet. It is necessary to find out how the POST request is signed (the signature field in the request payload). It looks like a simple hash of sha1, but from the looks of it, this is not it, but the Amazon's AWS Signature Version 4. Or I am doing something wrong and everything is much easier... Any ideas are appreciated, write to issues.
Parsed payload of license request
Copy headers and cookies of POST license request from browser to headers.py and cookies.py respectively like dictionaries.
pip install -r requirements.txt # if doesn't work try pip3
py l3.py
Input MPD URL: https://strm.yandex.ru/vh-ottenc-converted/vod-content/.../.../dash-cenc/sdr_uhd_hevc_ec3.mpd