Extra bends on GSC AVEP2S

The circuit-bent AVEP2S is still my favourite video tool. I was looking at some other video circuit benders work and liked a lot of stuff they were doing with chroma keys and control of saturation in an image. This inspired me to go back to the AVEP2S and add a few other nice features.

The first project was to add some simple chroma key functions. The signals that were easily available to do this are the PAL colour components “(R-Y)” and “(B-Y)” so they aren’t real chroma keys because there is a big component of luminance in them too. Still they help slice up the image. The keying circuit is built from a uA733 video amp (from the arc) to boost the signals feeding in to a comparator. I found the 733 amp really hard to work with – it seems very sensitive to DC biasing and impedance on the output. Any advice from readers on how to make effective use of this IC is welcome.

The other mod was to provide an input that can override the manual colour saturation control so that output can be varied dynamically.

Squeezing the Chroma Key Controls On The AVEP2S Case

With the additional keys you can get some really nice effects – particularly as you can modulate the key with an audio signal.

Screen Capture with Aditional Chroma Key