Building a Multiviewer

[bwalls]

I'd like to use an old Mac with a big screen to show a bunch of multicast channels simultaneously.

I know how to launch multiple instances of VLC with the different sources. I've figured out how to specify the location and window size, to a certain extent, though there seems to be an odd habit of windows opening in weird places.

Currently, though, I'm just getting a crop from the playing video, rather than the video scaling to fit my windows.

Here's what I have for one of the windows:
/Applications/VLC.app/Contents/MacOS/VLC --video-x=650 --video-y=22 --width=320 --height=240 --no-video-deco --no-autoscale udp://@233.4.178.11:30120 &

How do I have the video scale to fit the 320x240 window (with bars if it's 16:9 is fine)?

Has anyone already done this?