Firefox – Use Firefox to open an external program and pass the URL as a parameter, ie click to stream with MPC

I'm looking for an add-on or another way to have Firefox (or Chrome or anything else really) open an external program when clicking on certain links and send the URL I clicked to that program.

I know I can set a default action for the type of file that I want to play but then Firefox downloads the whole file and passes the path to the external program. I don't want the browser to download it, I just want to pass the URL.

I have a simple webserver with a directory listing of a bunch of movies. I want to be able to click on one of these movies on another pc and have the browser open Media Player Classic with the link I clicked as a parameter. I do not want to have the browser download the file then play it. I want to invoke MPC with the URL as a parameter.

I can open the link in MPC and it does what I want. I can start MPC with the URL as a parameter and it does what I want. I can also drag the link from the browser to an existing MPC window and it does what I want (This is what I'm doing now with MPC set to "always on top"). What I really want is to click the links and have the program start without downloading the file locally, probably by looking at the extension.

I will eventually look into setting up some kind of streaming service on the host pc, but for now I'd like to do it simply.

I tried a Firefox add-on called "Open Link in Program" (https://addons.mozilla.org/en-us/firefox/addon/olip/) but it does not send the complete link to the external program, only the domain part, so it's useless.

Basically, MPC has no problem streaming links from the webserver by being invoked with the URL as a parameter. How can I send the URL to the program?