Castle Patching 001: Digitizing Luma Video Sources

adc
dac
castle
patch-tutorial

#1

At the end of this exercise you should be able to digitize a video source and create a posterize effect. The first piece of gear I saw posterize on was on my first video mixer, the Panasonic MX-10, it had a rotary switch that you could use to select how many ‘slices’ of Posterizing you would have. You can do the same with this patch by removing any of the Data outputs from the DAC. Tools needed for this exercise are: Castle ADC, Castle DAC, and a video source.

First take your luma video source, I’ve used a simple ramp shape from the Visual Cortex H+V output, but you can use any video source. Take your video source and input it into the Castle ADC. Patch from ADC outputs D0-D2 to the DAC D0-D2 inputs, and from the DAC output to your video output. The Gain control on the ADC goes from non-inverted on the left through zero to inverted on the right. Set the gain to around 9 o’clock. Adjust the Bias control on the ADC until you can see 8 discrete levels including black. This patch constitutes the basic input and output of the Castle system.

Patch output:


DIY Questions:)
#2

Awesome post, thank you! Here’s my take on the patch with an additional trip through Staircase after coming out of the DAC.
Untitled%2001%204


#3


#4

Trying to wrap my head around how some of these Castles work on their own…

What would result if, in the patch above, you skipped the DAC and went from D0, D1, and D2 directly into R, G, and B of the encoder?

Or, alternatively, each of the individual channels (D0, D1, D2) on their own into the R? Can’t quite visualize what the quantization data looks like precisely.


#5

bypassing the DAC and going in to R G B, if the input were a simple gradient from left to right you would get color bars, starting with black, to red, green, yellow, blue, magenta, cyan, white. the bit sequence is, and if red is the first digit - 000, 100, 010, 110, 001, 101, 011, 111.


#6

Hm. Didn’t really “get” the Castle series before, but slowly starting to realize how much interesting territory could be opened up by sort of misusing the connections between the digital and analog worlds here.