Green Screen Effects on the Fly

Discussion in 'Digital Video' started by WerdAdmin, Jun 9, 2006.

  1. WerdAdmin macrumors newbie

    Jun 9, 2006
    Ok guys I am new to this forum because I desparately need ASAP. Anyone ever seen "Whose Line is it Anyways?". They do their news game where a guy is in front of a green screen. The guy has no idea what is behind him, but the crowd sees a totally different background and they play this game where the guy tries to figure out what is behind him.

    I need to replicate that effect and have it implemented within the next 2 weeks so I need some help fast.

    What I have in mind is my actor in front of a green screen, I film LIVE with a camcorder and feed it into my MacBook Pro via Firewire. Using some type of software and effects (that's where your help comes in) I need to change the background several times as he is talking and acting, and send the changed video out to a second monitor for the crowd to see. Remember all of this has to happen LIVE.

    Please help with what software can do this, whether it's Final Cut or something third-party. I know it will include chromakey. I have used chromakey myself on PC's in the past but the whole Mac thing is new to me. I am still learning Final Cut Express HD. I just HAVE NO IDEA how to do all of this instantly.

    Please help!
  2. LethalWolfe macrumors G3


    Jan 11, 2002
    Los Angeles
    AFAIK, it won't happen live w/o a video switcher that has chroma keying ability. Editing programs aren't meant to be used in a live video environment.

  3. evil_santa macrumors 6502a


    Sep 23, 2003
    London, England
  4. needlnerdz macrumors regular


    Jun 10, 2006
    low budget option...

    Hey there.. not sure how slick you are needing this whole thing to be, ie- does the person really have to be 'in' the video? Because the easist option that I can think of, would be to utilize a backwards projected screen image behind the person... low low budget, is to just place the person infront of a big ol sheet.. then place a video projector behind that sheet, and play the video you want behind them.. in dark settings, it can look quite decent- then if you are wanting this whole thing to be projected large scale for an audience.. just setup a second video camera, infront of the person_standing_infront_of_screen - and that will essentially 'flatten' the whole deal, and allow it to be projected large. Sure it will look quite goofy.. but hey, unless you have all the PERFECT found footage they do on the show, and get your lighting, perspective, blah blah correct, its going to look slightly goofy no matter what, so just exagerate that fact.

    - hey and thanks.. your little question just popped my macrumors cherry.. long time viewer.. finally going to contribute.. yet i am a bit worried about an addiction that could soon stem.. hope the advice helps.
  5. notjustjay macrumors 603


    Sep 19, 2003
    Canada, eh?
    I agree that a simple video switcher would probably be the easiest solution. The Videonics MX Pro DV should do something like that.

    On the PC there is a company called Serious Magic that has software that can do this kind of thing. I'm not sure exactly how "live" it can do, but it certainly did a good job of real-time chroma-keying.

    I agree that the rear-projection screen would be the easiest way to "fake" it.
  6. jaysmith macrumors regular

    Aug 13, 2005
    but with a rear projection screen would actually proje t the "secret" image. you don't want the guy in front of the screen to turn around and be able to see the image, thats the funny part of the skit.
  7. MacFan25863 macrumors 6502a


    Jun 20, 2004
    Like others have said, you will need a video mixer with Chroma Keying. The most affordable one I can find is the Edirol V-4. You may want to check with local video dealers about renting equipment.
  8. needlnerdz macrumors regular


    Jun 10, 2006
    blue screens...

    it may just be visible to me.. but i find it a bit funny that the google ads at the bottom of the screen go from three links about green/blue screens for video.. then the last link is for the blue screen of death... something that shouldn't be familiar to mac users.. found it funny.. ha ha... ha..
  9. bigandy macrumors G3


    Apr 30, 2004

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