capture a picture live from a camera-Que

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Micha Messermann

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May 2, 2021, 9:21:43 AM5/2/21
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Hi, is it possible to capture a picture from a camera-Que?

Situation is the following:

- I am solo player – no technician. I’m on stage. I have the MacPro backstage and it is controlled via Qlab-Remote.

- I have a camera (Iphonecamera/syphon with Airbeam) on stage filming. This is projected live with a beamer.

- At a definite moment I want to “Capture” (I hope this the right word.. I want to “take a picture”) from this live stream and use it later on.

Or in other words: while playing and having the camera on stage live on screen, I want to take a picture (for example jpg..) from this life-Stream and use this picture few minutes later on the screen.

Thanks for any input on this :-)

Sam Kusnetz

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May 2, 2021, 9:58:11 AM5/2/21
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Hi Micha

You can’t capture an image from a Camera cue using QLab alone, per se, but what you can do is:
  1. Start the Camera cue playing at 0% opacity
  2. At the moment you want to capture, use a Pause cue to pause the Camera cue, which will freeze its input.
  3. At the moment you want to show the audience, use a Fade cue to fade the opacity of the Camera cue up to full.
  4. The image the audience will see is the paused moment.
Good luck!
Sam

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Micha Messermann

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May 2, 2021, 10:08:42 AM5/2/21
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aah, sure, that sounds like a very good solution! I will try that.. Thanks :-)

micpool

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May 2, 2021, 2:12:53 PM5/2/21
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You can capture a still of an entire display to a file and use it in a video cue with this script

--requires a pre existing video cue numbered "STILL"  with surface set for your display

set theDisplaynumber to 2 --set to number of display or projector for frame capture

set theFolder to "~/Desktop/screencapture/"

set thepath to path to home folder as Unicode text

do shell script ("mkdir -p " & theFolder)

set theInstruction to "screencapture -x "

repeat with display from 1 to theDisplaynumber

set theInstruction to theInstruction & theFolder & display & ".png "

end repeat

do shell script theInstruction

tell application id "com.figure53.QLab.4" to tell front workspace

delay 0.5

set the file target of cue "STILL" to (thepath & "Desktop:screencapture:" & (theDisplaynumber as string) & ".png")

end tell


This uses the shell command screencapture to screenshot all displays and then selects the image you want as the file target for a preexisting Video cue numbered "STILL" (option -x stops the capture sound effect playing)

If you don't know the display number of your projector then do a normal screenshot with  command shift 3 and look at the numbers in brackets on the file names of the image files on your desktop,

This method has the advantage of  targeting a cue to an actual image, and is also easily expanded to any number of framestore files and corresponding cues by duplicating the script cue and changing the cue number of the cue whose file target is changed  and the file that is targeted e.g.


--requires a pre existing video cue numbered "STILL1"  with surface set for your display

set theDisplaynumber to 2 --set to number of display or projector for frame capture

set theFolder to "~/Desktop/screencapture/"

set thepath to path to home folder as Unicode text

do shell script ("mkdir -p " & theFolder)

set theInstruction to "screencapture -x "

repeat with display from 1 to theDisplaynumber

set theInstruction to theInstruction & theFolder & display & "A.png "

end repeat

do shell script theInstruction

tell application id "com.figure53.QLab.4" to tell front workspace

delay 0.5

set the file target of cue "STILL1" to (thepath & "Desktop:screencapture:" & (theDisplaynumber as string) & "A.png")

end tell

Demo Screen recording and workspace attached

Mic

FRAMESTORE.mov
Frame Capture.qlab4.zip

Micha Messermann

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May 12, 2021, 11:15:18 AM5/12/21
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Hi, just to give a short responce after playing around with that:

@sam kusnetz: your solution with a pause que is working really very well! Thanks

@micpool: Thank you so much for your allways very advanced solutions! I guess yours is a perfect way to do it, but with my little programming-knowlegdge, I went the easy way with the pause-que.. but I really appreciate!
:-)
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