johnhlee@cory.Berkeley.EDU (John Lee) (07/24/89)
The discussion about genlocks has reminded me of an idea I had a while back. Correct me if i'm wrong, but I believe (at least most) genlocks know when to inject live video in the output image (ie color 0) by a pin on the video port which changes state whenever the data coming out of the RGB lines is color zero. ie, as the video image is scanned this pin goes high or low (i don't know which) when the background is being scanned. What I was thinking was this: I remember that the old commodore genlock for the 1000 converted the incoming video to RGB and showed the genlocked image on the RGB passthru (since this is just an analog-to-analog conversion, this doesn't surprise me). I don't know if any of the genlocks on the market (or which) do this too. The ones i've seen only have composite out. Anyway, if you built a little circuit which looked at the RGB signals on this line and outputted a digital signal depending on how "blue" the output was, you could feed this signal back into the genlock instead of the color0 line and have a primitive and CHEAP chroma-key. True, you couldn't have any blue hues in your computer graphics, but whadda you want for (almost) free? Any replies? would it be fast enough? Please don't chastise me too much if i've said something dumb, though. - Vince Lee (now back from Europe), using my brother's account since berkeley doesn't think Mech E's deserve computer time.
silver@cup.portal.com (Jim B Howard) (07/25/89)
Speaking of Chroma key, are there any Amiga genlocks that can do it? I'm willing to spend up to 5 grand to get this capability. But I cannot find one single company that sells them! I've scoured through every video magazine in existence, and *NONE* of them sell any kind of chroma key equipment. It doesn't seem as if this should be such a hard feat to acomplish. After all, every news station has one for their local weather guy. I cant believe there are no amiga products with this capability. If anyone has any info, no matter how inacurate, let me know. I'm stuck.
bob@jacobs.CS.ORST.EDU (robert s. richardson) (07/26/89)
In article <20715@cup.portal.com> silver@cup.portal.com (Jim B Howard) writes: >Speaking of Chroma key, are there any Amiga genlocks that can do it? >I'm willing to spend up to 5 grand to get this capability. But I >cannot find one single company that sells them! I've scoured through >every video magazine in existence, and *NONE* of them sell any >kind of chroma key equipment. It doesn't seem as if this should >be such a hard feat to acomplish. After all, every news station has >one for their local weather guy. I cant believe there are no amiga >products with this capability. > >If anyone has any info, no matter how inacurate, let me know. I'm stuck. Chroma key is not usually a function relegated to a separate device, but is a part of the production switcher. (The thing with all the lights and levers and joysticks on it.) You can pick up a small 8-channel one with chroma key for about $3500, but you must also have cameras that can sync to an external source, such as your Amiga. If you don't you'll also need a time base corrector, another $4000. But have no fear! The A-Squared folks have SOFTWARE that in conjunction with their LIVE! board will do rudimentary chroma-key, and I beleive Digital Creations (Makers of supergen) has something similar in the works for their Living Color series. Hope that helps, | Bob Richardson (or, for you UNIX buffs: bob@jacobs.cs.orst.edu) | | 218 NW 21st #2 Corvallis, OR 97330 503-758-5018 | | "They have taken my Jesus and locked him up in a church!" - Unknown |
Sullivan@cup.portal.com (sullivan - segall) (07/26/89)
>Speaking of Chroma key, are there any Amiga genlocks that can do it? >I'm willing to spend up to 5 grand to get this capability. But I >cannot find one single company that sells them! I've scoured through >every video magazine in existence, and *NONE* of them sell any >kind of chroma key equipment. It doesn't seem as if this should >be such a hard feat to acomplish. After all, every news station has >one for their local weather guy. I cant believe there are no amiga >products with this capability. > >If anyone has any info, no matter how inacurate, let me know. I'm stuck. ^^^^^^^^^ well vague anyway --/ A chroma key system was demoed at the Amiga Festival in San Francisco, June 17 & 18. Perhaps the owners would know how to contact exhibitors. The festival was held in the "Concourse Exhibition Hall" at 8th and Brannon Streets, San Francisco, CA. Sorry I can't provide any more detail. (The demo was rather impressive though...) -Sullivan Segall _________________________________________________________________ /V\ Sullivan was the first to learn how to jump without moving. ' Is it not proper that the student should surpass the teacher? To Quote the immortal Socrates: "I drank what?" -Sullivan _________________________________________________________________ Mail to: ...sun!portal!cup.portal.com!Sullivan or Sullivan@cup.portal.com
jgary@ms.uky.edu (James E. Gary) (07/26/89)
In article <11832@orstcs.CS.ORST.EDU> bob@jacobs.CS.ORST.EDU.UUCP (robert s. richardson) writes: >But have no fear! The A-Squared folks have SOFTWARE that in conjunction >with their LIVE! board will do rudimentary chroma-key, and I beleive More info please. I have a LIVE!, but have heard nothing about this. I saw a demo of a program called something like "Mandela" about a year ago that had computer graphics interacting with LIVE! images. Is what you are talking about related to this? Let me see...if I stand against a high contrast background and digitize in black and white, then I can have the outline of my body be in the background color and everything else in another color. I can then super-impose my solid background color shape on top of a computer generated picture, turn on the genlock and have me in live video show through. Yeah, that might work. The problem I have is that my genlock (from Commodore, you know, the cheap one) shifts the screen image a few pixels so I won't be lined up well with the 'hole' in the picture. Do all genlocks have this effect, or is it just the Commodore model? Hmm. Now all I have to figure out is how to clip my shape out of the digitized screen and overlay it on the background graphics. That should be a simple blit operation, shouldn't it? This sounds like fun! Time to dig into live.library! Hints and suggestions welcome. Also any pointers as to where the "mandela" software may be obtained. -- +-----------------------------------------------------------+ | James Gary jgary@ms.uky.edu | Yeah, I have a light, | | University of Kentucky | my face and your butt! | +-----------------------------------------------------------+
prem@geomag.fsu.edu (Prem Subrahmanyam) (07/26/89)
I thought I saw that the SuperGen claimed to do chroma...and it's only about $900 or so....maybe I'm wrong, but I KNOW I've seen some gen or other claim to do chroma key. If not, I'm almost sure that the Video Toaster is supposed to. Again, I'm not very sure about any of this, my best recommendation is to go to your local dealer and check out all their genlock-type products, I'm sure that whichever one is supposed to do chroma key will say so right on the box. ---Prem