(for Sony Vegas) If a visual only contains a still image, then I use the Masking in Pan/Crop. If its a moving visual, i either use the Pan/Crop masking orr Chroma Keyer if possible
It mostly depends on the background. For example, i used Chroma Keyer for the moving visual at the top right. The background of that visial contained mostly one color and a gradient. Having one background color makes it much more easier. It also works well with gradients. I also mask out anything from the background that isnt the same color.
