This is basically a comparison of free sofwtare that you can install on your NAS or headless linux machine, I am using Debian Bullseye, but that is besides the point
To run webm files (VP9) through miniDLNA, all you need to do is rename the file !
My atom PC (D525) is not capable of transcoding on the fly, so i keep it, and i wrote a script to execute the following command for webm video files (and any other unsupported file) by browsing to the file in the web browser, then clicking on it, a simple script but explaining how to install it is going to take some times with permissions and server config, so i will probably be posting it online and explaining in a different post when i have the time
ffmpeg -y -i output.webm -c:v libx265 -b:v 2600k -x265-params pass=1 -an -f null /dev/null && \ ffmpeg -i input -c:v libx265 -b:v 2600k -x265-params pass=2 -c:a aac -b:a 128k TEMP_OUTPUT.mp4
the most popular of the bunch is MiniDLNA, it does not transcode, and on openWRT it does not even serve video, so it is a good option when you have a PC storing the files, and you don’t need transcoding on the fly ! for some devices that are capable of running VP9 like modern 4K TVs,all you need to do is rename the file !
Universal Media Server : Universal Media Server is a DLNA-compliant UPnP Media Server. It was originally based on PS3 Media Server by shagrath.
OSMC
Streama: Self hosted streaming media server.
Gerbera: Free UPnP media server based on MediaTomb