Isadora running through Qlab for one scene?

  • Hi, I have a stage show running in Qlab, and I'd like to use the chromakey/greenscreen function in Isadora for one scene. There would be a live feed from a camera onstage. I can't find any info online about how to make this work, if it's possible, etc. Any advice would be deeply appreciated.


  • It will depend on the platform you are using. If you are on Mac it should be trivial to send a syphon video between the two.


  • If you are on Windows I know some have enjoyed using Spout or Wyphon to do similar - though I have not used them recently enough to be able to provide details.


  • Sorry, running on Mac.

    I've never used Syphon. I went to their site, but I wasn't clear on how to find the exact interface for this specific task. 

  • Now that I think it through, I should have known you were on Mac if you are using QLab. ;)

    Isadora and QLab both include syphon support. You can download their client and server demos to get a sense of how syphon works. You might also grab the software Syphoner that allows you to grab a screen from any open software and send it through syphon.

    Once you have Syphoner running you can open a Syphon receiver in Isadora and see how you can now manipulate that stream like a live video with filters and whatnot. 
    According to the QLab site you need the Pro version to access Syphon features.
    In Isadora create a Syphon Stage Output actor. This is assuming you are on Isadora 2.2.2\. (it was called Syphon Sender in an earlier version if I remember correctly.)
    This will send an stream of a chosen stage through syphon.
    You can then create a syphon camera cue in QLab that points to the steam coming from Isadora. 
    Good Luck!

  • Phew, OK, I'll try all that. Gotta learn fast!


  • Hi Michael,
    I've done this for a show : Main show running with QLab (playing movies on different surfaces, sending titles... and sometimes a live camera)

    Isadora was : aquiring the live camera, cropping video feed, brightness/contrast/saturation corrections, freezing/unfreezing video feed (triggered via midi from QLab), and finally sending it to QLab via syphon.

    See my attached patch.
    Launch first the patch with Isadora, select your live source from the Live Camera settings, activate. You should then see your image in the preview window. Then "force stage preview" from the output menu to activate the syphon output.
    After that launch QLab, in the settings under Camera patch, you should find "IsadoraCore - Stage 1". That's all !