garageCube

Can I make my video clip react to music (bounce/color organ/audio fft analysis) if my video clip DOES NOT have an Alpha channel?

yes, you'll just see the edges

Edges of what? Will it make the image look bad? How much of the "edges" will be shown?

Edges of what? Will it make the image look bad? How much of the "edges" will be shown?

When your video gets smaller or moves around the you start seeing the edge of your frame. So instead of image reacting to the sound as you would see if you use image on transparent background, you get the whole picture from edge to edge.
But why do you ask and not try to see yourself? And make sure you understand what alpha channel means.