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Anti paddle jitter algoritms

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Has anyone ever tried to fix paddle jitter by code? Simple averaging seems to be too simple to really work.


Here is my idea for an algorithm:

; n = number of frame
; inp[n] = paddle value of current frame
; out[n] = jitter suppressed resulting value

factor = 0.0 .. 1.0                             ; e.g. 0.5 (1.0 means no jitter suppression and immediate response)
dfactor = factor ^ (1 / abs(inp[n] - out[n-1])) ; the larger the paddle delta, the less jitter suppression
out[n] = inp[n] * dfactor + res[n-1] * (1 - dfactor)

Due to the math, this cannot be implemented 1:1 in 6502 assembler, but an ARM based game could use it. And Stella too.

Does anyone have a better idea?

Edited by Thomas Jentzsch
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The major reason of my question: The R77 console produces a very hefty jitter (~3 pixel!). They tried to compensate that with some very primitive code, which caused the paddles to respond that badly. Over the last days, we did enhance Stella with a configurable dejittering. Seems to work pretty well for us. :)

The next R77 image will show if it works for everyone.

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  • 4 weeks later...

This has been raised a few times, and generally I respond that a median filter of size 3 would likely work great. 1, 2, 3. (probably more) :)


Median filters are fantastic with salt and pepper type noise, which seems to be the same kind of noise jittery paddles put out. You would need a handful of bytes, but nothing very onerous.

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