Ramping brightness (amplitude) in Procyon

I noticed in a session last night that the ramping of amplitude from 255 to 0 and vice versa does not seem to be a smooth process in the Procyon. I definitely experienced some very significant "stepping" in the brightness levels in the session I created.

I mentioned this in another post this morning - here's a quote:

Quote:

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I'm not sure I like how the Procyon handles ramping in brightness. I might be doing it wrong, but when I reached certain levels of brightness (or dimness(?)) there was a very pronounced stepping from one level to the next.

I ramped brightness by travelling from amplitude 255 to 0 and vice versa for the red channel and I noticed the light suddenly disappearing and suddenly appearing with a pronounced difference in brightness that I wouldn't expect if this quality was supposed to be ramped over time.

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Could I get some feedback from MindPlace on this?

It seems to me that in the earlier stages of brightness ramping that the changes are imperceptible. I thought at the time that this might be me, but when the color shut off and shut on, the difference was so significant that I began to suspect that the process of dimming and brightening isn't that smooth in the Procyon.

Am I just doing it the wrong way? Or is there a constraint to gradually changing amplitude over time that I should be considering when programming?

Regards
Caleb

Hi, Caleb--

The eye's response to light is nonlinear, and the brightness changes in the Procyon are currently linear--hence the perceivable steps at the edge of brightness. Though most users don't notice this (which was even more pronounced in the Proteus, with its 16 brightness levels), it could be possible to reduce it in the future by either using a nonlinear look-up table, or a larger number of linear brightness levels--say, 4096 (12 bits vs. current 8 bit value). I'll put that one on the list of things to do!

--Robert

Ah - that might be it.

In working with music I quite often use the MIDI format for parameter control which uses values of 0 to 127.

This isn't too bad, but compared with the VST format which uses 32bit precision, there can be a noticeable difference in "smoothness" when modulating something.

On the other hand - the steps are only really noticeable to ear if you modulate via MIDI quickly enough to hear the "steps".

Having said that - I don't know the equivalent in regards to light linear vs non-linear etc...

But do you find "stepping" when you try to modulate the brightness of the lights over time? I still wouldn't mind confirming the experience with someone else on the very unlikely possibility that it is actually a fault with my machine.

Regards
Caleb

I do notice stepping, especially at low brightness levels, or with certain color combinations. Maybe we need to move to 4096 brightness levels in the future...?

Robert

Sounds like a good plan Robert.

Regards
Caleb