Discuss video feedback techniqiues here.  Video feedback is where
you point a video camera at a monitor causing the video signal to feedback.
This produces a variety of swirling psychadelic patterns, and fractal
mossaics.  This can be combined with images either on transparencies or
next to the screen to create a swirling hall of mirrors effect.

3 responses total.

Back in my public access cable TV days, we used to feed back electronically
thru a frame buffer.  We did this by using the output of a VCR, which got the
switcher output for recording purposes.  In the East Lansing cable studio,
the VCR signal was fed thru a frame buffer to get it synced to the rest of
the system, so we got a ~1 frame delay in the feedback look. The effect was
very cool, with mostly black background with red, green, and blue lines
drifting away to one side or another.  Movement in the image led to echoes
(we'd mix or chroma key with a camera).  Playing with the color knobs on the
(I guess is was a "genlock"?) frame buffer changed movement, color, etc.

        Can you feedback an image using this technique, or can you just
use it to get abstract feedback patterns?  Both are cool, but obviously
different effects. Do the abstract patterns look anything like the colored
bars on the display panels of the computers on the old Star Trek?

Well, we'd feed in a camera signal of people with a chroma-key blue
background, and the background went to black somehow.  I'm starting to get
fuzzy on the details, especially since the cable station tech outlawed that
technique after a while (claimed it was burning out clock crystals in the
cameras).

The colored lines where very fine and tended to flow in random ways.  I don't
quite recall what the old Trek stuff looked like (another good reason to put
TOS back on the air!).

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