IP camera's RTSP streams are added via its url and shown in the classic tile configuration. The number of tiles is automatically choosen based on the number of configured cameras: a single camera goes full screen, adding more cameras the app switches to a grid view: 2x2, 3x3, 4x4 and so on.
The maximum number of cameras is determined by the device's capabilities.
The stream decoding and rendering is demanded to VLC's library: without their effort this app wouldn't be possible.
This app was specifically developed for F-Droid, as I couldn't find any open source RTSP vievers in the main repository.