Replace video background with Greenscreen background

I recorded an instruction video using my webcam but I want to replace the background which is a cluttered room with a green screen or other neutral background. Can I do that in Shotcut?

No.
That’s back to front thinking.
You must shoot the video with a ‘green screen’ background to begin with which in post production you can replace with any background of your liking. Removing a background in video [or knocking out an object] requires techniques like rotoscoping which Shotcut is not capable of.

Thank you Steve! That was exactly the direct answer I was looking for. -Cheers!

If i shoot a video with a greenscreen, where can i find the option to replace the greenscreen with background of my choosing?

You need to use the Chroma Key filter. See this short tutorial.

Shotcut seems to work like most non-linear video editors, which is to say you have to have the image in the track below that which you’re using a green screen effect. You have to use the Chroma Key filter on the track that you want to see against a background of your choice.

Unlike Final Cut Pro X you have to apply an effect directly to a clip. When you understand that nothing done in Shotcut exists in isolation (in that you have to apply a text or visual effect to something that’s in a track of your project).

In other words, let’s say Track 1 (V1) has an image (jpg) you want to green screen yourself in front of. On Track 2 (V2) you’d place the video that you want to green screen by applying the Chroma Key filter though it’s not always that simple in that you might – as I did – see a bit of fringing.

If that happens, add Alpha Channel: Adjust to Track 2 and tweak accordingly.