The Framebuffer Loopback Source reads video data from the current framebuffer and treats it as a data source for an effect. Using this plugin allows you to display something like a file or captured video, then read the display back and put it through another effect. By layering a number of different effect plugins very complicated visuals can be achieved.
You can also use this to do "grab & hold" style effects, where you feed the framebuffer through an effect repeatedly, compounding the effect until the image decays or distorts beyond recognition.
The Framebuffer Loopback source was initially designed for doing one thing: Video feedback. If you've ever pointed a video camera at a TV displaying the output from that same camera, you've seen video feedback. Take a picture, apply a small change to it (zoom, rotate, shrink, bend, tint) and then paint it back out again over top of itself, usually with alpha blending so you don't completely replace the previous image. Repeat the process really fast and things get really interesting. Pretty much any MidiVid plugin that distorts an image can be used to create cool feedback effects. Experiementing is encouraged.
For starters, try this:
|MidiVid GPU Version 1.0
Copyright (c) 2005 Jason Dorie and VUTAG
Generated on: Sun Jan 25 23:45:41 2009