View Full Version : Chroma Key
roba000
7th September 2002, 06:29 PM
Hye, do u know any software
like resolume, motion dive, etc to make chroma-key live???
eXhale
7th September 2002, 06:36 PM
Resolume can do this
MoRpH
7th September 2002, 09:05 PM
SVi can key on pure black.
burstingfist
8th September 2002, 06:16 AM
visualJockey has live input and many different ways to key the input. I use a joystick to control the threshold with the y-axis and the mix level with the x-axis
vjpixylight
8th September 2002, 07:40 AM
Motion Dive
MD uses a layering process that is a bit different from color keyed video, called inking, and is, IMHO, a far better, and cleaner way of layering video with that kinda color keyed like mix...
MoRpH
8th September 2002, 08:03 AM
Transzendent also uses an inking like layering methods, look for full description in my up coming TZT review :)
holly
27th September 2002, 04:51 PM
Chroma-key is the blue/green screen background. It's the most reliable solution for compositing -- especially with cgi where the background is a perfect, pure color. Shadows and dark colors are all preserved 100%. Can't use halos, lensflares, or partial transparancy (wispy hair) unless your using a $10000+ Ultimatte hardware box or processor-intensive After Effects plug-in, so it's limited for practical VJ use. Strictly an "in studio" solution, and I convert all my chroma-key clips to black backgrounds for luma-keying live.
Luma-key is simple and just blends the lighter pixels together while ignoring the black pixels. Anything on a black background can be luma-keyed with nice results and every VJ software has some sort of luma-key mode like the "Ink mode" in MotionDive. My mixerboard has a luma-key that makes the black pixels transparent to show the second feed underneith. Problems are shadows and darker colors that become transparent, and an undesirable bleed-thru of brighter pixels. Remember cheap sci-fi from Saturday morning cartoons where the stars showed through the planet...?
Holly.
MoRpH
27th September 2002, 04:58 PM
Some apps and hardware mixers actually let you set the colour that is keyed with the chroma-key function, rather than just blue.. and its still called chroma-key cause technically chroma = colour so the term can cover keying out of ANY colour, but is standardly pure blue
fluchtpunkt
27th September 2002, 07:27 PM
Originally posted by MoRpH
Some apps and hardware mixers actually let you set the colour that is keyed with the chroma-key function
...& even the tolerance (i.e. keys not just one color, but also 'similar' colors).
having control over the chroma's tolerance is what makes it such a great thing for (live)mixing (in my opinion @ least). unfortunately i havent found this feature in a vj-soft yet :confused: (i do it either with afterfx or a hw-mixer).
elbows
27th September 2002, 08:11 PM
I think you can control the tolerance of the chromakey effect in the free nasharts package of visualJockey now, with the latest update to that package that came out the other day. I havent had a chance to try this yet though.
fluchtpunkt
27th September 2002, 08:19 PM
this (nasharts-[3.20.28.29]) is the version they have on the page... nope, no such function (or i'm too stupid :) ).
elbows
27th September 2002, 08:24 PM
Theres lots of "unofficial" plugin updates but they only mention them on the forums.
Heres some links:
http://www.visualjockey.com/freedownloads/plugin/nasharts-[3.30].exe
If you want to use high res video input then Pete Warden wrote some lovely free plugins and theres a deinterlacer there that works a treat:
http://www.petewarden.com/downloads.htm
fluchtpunkt
27th September 2002, 10:00 PM
wonderful the new chroma :cool:
...no more trying to get that same effect via masking - or some other strange combination of effects :) .
cheers
Meierhans
29th September 2002, 03:38 PM
If you got a Capture device that supports 640 *480 you can use video-in & petes deinterlacer in combination with nashs chroma-key to key in 640*480 best quality. Runs at my pc at 25 fps stable. But you ain`t got much space for other effects then.
USE
6th February 2007, 09:47 AM
is the resolume chroma keying that rgb tab in the layer pallette?
so if i want to prep some clips for chroma keying, i have to make it one of those pure colours. is there a specific shade of colour that keys best?
holly
6th February 2007, 10:21 AM
R=0
G=0
B=255
in hex:
#0000FF
This thread is 5 YEARS OLD!!!
http://cache.consumerist.com/assets/resources/2006/08/zombie_grave600-thumb.jpg
PilotX
6th February 2007, 10:39 AM
kerbump indeed.. could this be a record?
nice pic holly :)
use - no.. the RGB select buttons turn the channel off entirely - I don't actually know, but Iassume that this means that if you turn off the blue channel the B value for all pixels with be set to 0.
does resolume have a chromakey natively? I've never used one, luma keys yes.
lumakey sets all pixels with an RGB value as specified as being transparent. it is best, as holly says, to use pure blue or pure green (blue clashes less with skin colours, filming against a green screen needs less light to get a cleaner green. apparently), especially if you are doing it in a studio.
if your background is pure blue, and there is no blue anywhere else in the picture, you could turn off blue and then luma key I guess, but I would expect that your picture would change colour slightly, or noticeably.
USE
6th February 2007, 10:44 AM
but someone said that resolume has chroma keying, but i have never found it (was tryign to avoid admitting that).
if anyoen can tell me how best to key out blue and green that doesnt involve deleting a colour channel then luma keying it, id be well happy.
shahar
6th February 2007, 11:29 PM
Vjamm Blueprint (link (http://www.vjamm.com/blueprint/manual/manual_params_coloralpha.html))
robotfunk
7th February 2007, 12:54 AM
http://vjfx.com/vjfx_store_sys.php?op=VJFXStoreProd&prod_id=514
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