VLC

VLC can read a stream from the server in several ways. The recommended one consists in reading with RTSP:

vlc --network-caching=50 rtsp://localhost:8554/mystream

RTSP and Ubuntu compatibility

The VLC shipped with Ubuntu 21.10 doesn't support playing RTSP due to a license issue (read here and here). To fix the issue, remove the default VLC instance and install the snap version:

sudo apt purge -y vlc
snap install vlc

Encrypted RTSP compatibility

At the moment VLC doesn't support reading encrypted RTSP streams. However, you can use a proxy like stunnel or nginx or a local MediaMTX instance to decrypt streams before reading them.