Sending Commands to Existing VLC Instance or Adding Custom RC Commands?

[homsar47]

I'm trying to toggle the opacity of a filter on runtime and can't figure out any possible way to do this with the CVLC command line interface, or with existing RC commands. It's trivial to use a command to set my desired opacity with the command line arguments, but I am unaware of any method that allows this to happen while a video is in progress.

The end goal is getting a serial port analog value from my Node.JS instance to modify VLC output, but I'm at a loss for an easy way to do this. I'm running on Raspbian.

I understand I'd need to compile from source to modify this, but firstly, I wanted to make sure there wasn't an easy solution I'm missing.

If there is no possible way to do this with existing RC commands, and no way to send a command to a "live" VLC instance, are there any resources that might be helpful for what I'm trying to accomplish? Would I need to modify libVLC as well, or just the relevant VLC modules?