Serviio

I have this running and it's very sweet running on the Raspian Buster minimal install and serving 4K video without spooling or cogging.
I'm using an 8TB 3.5" HDD on a USB 3 adapter.

In fact I started out building a NAS for a backup for the 8TB library but I saw that there was room in the box for two HDD's and their power supplies, so I put the library in there as well as the backup drive (a read-only mirror of the library using rsync).

Then in a rush of blood, I installed serviio and it just worked as expected.

I'm chuffed.

Make sure to connect the gigabit router with the Cat6 Network Ethernet Cable to your HTPC to make sure you will benefit from the high transfer speeds.