Green screen



  • Hello everybody.

    I had a phone call where a theatre production wants to play with green screen and live camera on stage.
    Does anyone have any experience with keying out the green screen with a live camera on stage and then composite different background with isadora?
    Klaus K.

  • Tech Staff

    Chroma Key actor :) (or maybe luminance) -  easy peasy :)



  • But with good result? I know the actors, but I want to know if anyone have any experience with the same settings.



  • Hello,

    I have made some experience with students during workshop, here are my conclusions:
    — like every green screen, quality of light and camera are priority, separate lighting for background, key light, backlight, preferably 4.2.2 camera with real video in, like blackmagic.
    — Isadora chromakey works but is far away from real key software and hardware
    — there is a time delay, so no lipsync
    — it's really computer consuming, so dont hope to play and mix many other clips in realtime.
    But nothing better than your proper test with your hardware and hopes…
    All the best,
    Jacques Hoepffner

  • Tech Staff

    Great lighting and a perfectly straight and constant green material is needed too. But as Jacques said above it is time consuming.



  • Thanks a lot.

    Great summary of your workshop Jacques.
    Klaus K.


  • MIght be worth looking at this new FFGL plugin, if you are using Isadora 2.0 beta.
    http://troikatronix.com/troikatronixforum/discussion/1592/chroma-key-with-ffgl-in-2-0#Item_1

    I havent tested it yet myself, so if anyone has reports, please post them here :)



  • Sorry I'm the one who posted the link above, starting a new discussion while yours was just about the same subject...
    I discover and  tested this FFGL plugin just very recently, but it's a big improve compare to the original one, wich is to my point of view just unusuable.
    It seems to be an adaptation of a Resolume original plugin. In Resolume, there is much more posibility to finely set the effect, with a much better result. In Isadora the functions "Feather"  and "Ramp" seems to be just inactive, so the edge of mask is very rough.
    About delay, it exist but is not that bad, can't say in images, nothing compare, again, to the old stuff...
    One thing I wonder is that the "Video in watcher" actor is outing in vd-cpu mode. So I have to use a "video to Texture" actor to convert the signal and be accepted by the FFGL Chroma-Key actor. I guess it's time consuming and wonder if there is a way to avoid it...

    My test : HD camera connected in HDMI on a Black Magic Studio. Isadora 2.0b12 on Mac Pro 3.1, 2x2,8 Ghz with  GeForce GTX 660



  • For live green screen in a theatre setting I absolutely LOVE doing green screen/blue screen work with a Reflectmedia kit:

    http://www.reflecmedia.com/broadcast/products/chromatte/index.htm
    You can use what ever tool you want to do the key - what matters is the quality of your source image.
    -Alex


  • The new kinect does much cleaner background subtraction than the last one. Lower latency too. Its very impressive!

    Windows only though and the sdk is still in Beta at the moment.


  • @laurentR

    For what it's worth: none of the CPU based plugins are going to perform well with HD. In the old days of 640x480, they were quite usable. But for 1920x1080, they just can't handle the bandwidth. That's why 2.0 + FFGL is the path everyone must adopt for the future.
    Best,
    Mark


  • Another option for live chroma keying might be PixelConduit (FREE) with the $19 Video Link upgrade which will give you Syphon support. Conduit was designed primarily for live production work so might be worth checking out?

    I've been using the plugin version of Conduit for years in Motion and it has proven it's worth on many occasions when a nodal approach to compositing has been required.

  • Tech Staff

    @Unfenswinger

    A few years ago I have tried PixelConduit but had to much crashes to work on a production with it. But maybe worth trying again.

    Best
    Michel



  • green screen is hard, if you have great lighting, on the subject and the screen and a good camera (442- better colour reproduction) you can start to work. I would seriously look at renting hardware for this. The blackmagic ATEM switcher 2me has a pretty good kery inside it, it is a cheap piece of kit- under 2k and rental therefore is also cheap. You can run an SDI camera into it and feed your background into another input and you have your composite without touching anything in Izzy- leaving your machine free for making everything work. The other great advantage is that you will have only 1 frame latency if you output the image from the mixer, if you want to put it back into your computer for mapping you only have the roundtrip delay no processing.

    The other solution to look at is TSPS
    http://www.tsps.cc/
    It might help, with proper lighting you can use background subtraction and send the mask over syhpon.

  • Tech Staff

    So maybe this could be a new thread: to find FFGLs for the effects we used till now. For example I cant find a simple motion blur, I only find blur.

    There are others that would be also great: Luminance Key, HSL adjust, ...



  • Tech Staff

    @primaldivine Is there  a motion blur in that list for mac? I cant find any plugins on the petewarden site, because there is a plugin listed "Petedirectionalblur" on your link



  • an interesting framework on github for iOS gpu effects... its not FFGL.. but related I suppose.
    http://www.sunsetlakesoftware.com/2012/02/12/introducing-gpuimage-framework



  • @primaldivine,

    Are you familiar with the Interactive Shader Format developed and made open source by the VDMX guys?
    [http://vdmx.vidvox.net/blog/isf](http://vdmx.vidvox.net/blog/isf)
    It would allow potential hundreds of GLSL shaders from [Shader Toy](https://www.shadertoy.com) and [GLSL Sandbox](http://glslsandbox.com) to be made accessible in Isadora. The Shader code needs to be modified with a header to publish the inputs but it appears relatively easy. While not as powerful as FFGL there does appear much more community activity in developing GLSL shaders which we could all benefit from.
    The downside is that it is Mac only ATM but I wondered if it was something that would be of interest to Isadora users?


  • This was discussed at the meetup in Berlin wasn't it?

    I can't remember the outcome but I guess new features aren't top of the list at the moment.
    +1 from me though.
    Would it be possible to write a FFGL plugin which can dynamically load isf files?

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