On Apr 5, 2006, at 5:55 AM, Peter Forde wrote:
In Gem, does anyone know how pix_levels works. I just want to kill
all the reds or greens in a video. I don't understand the floor/ ceiling stuff.
...ok, no one answered how pix_levels works, so I'll try...it's alot
like the "levels" option in Gimp or photo$hop: they all allow you to
control the levels of color channels, either individually or together...
...[pix_levels] has a few different modes: auto, auto+uniform,
uniform, and "other"...when "auto" is on, the object automagically
assumes it knows most of the bandwidth you'd like to deal with, and
so you really just need to tell it what to do with individual
channels...for example, if you just want to remove the red channel,
set auto on, then send [0 1 0 0< to the third inlet...(this reminds
me that it might be better to have a named message here, so maybe in
the future we can have a [red 0 1 0 0< to do the same thing)
...the uniform mode takes one message for the RGB channels together,
and this goes to the 2nd inlet of [pix_levels]...this works more as
an overall lightness/darkness control for the image...
...the floor/ceiling stuff has to do with how much bandwidth of the
color(s) you're dealing with, and you usually have seperate in/out
floor/ceilings...so, if you have [0 1 0 1<, you have the full
spectrum of the channel output...
hth,
james