2 simultaneous sessions on different devices/IP’s = inconsequential. A 3rd simultaneous session = auth tokens revoked on all authorised devices, and you get a warning that lasts for 1 week. If 3 simultaneous sessions occur again within that time then your account gets removed.
Losslesscut is what you want for this. It’s basic and concatenates without re-encoding. And it’s open source (as is handbrake)