Suggestions wanted: MST3K-esque shadows

[Dave H.]

Our small theater group is trying to figure out if we can duplicate Mystery Science Theater 3000's "shadowrama" effect.  I've found a few guides on how to do it after-the-fact using Adobe AE or Final Cut Pro, but we're trying to do it live, and we'd greatly appreciate a few suggestions.

We've got 3 of the 4 steps solved:

- any arbitrary movie, playing on the bottom layer of a surface.  Done - this one's trivial.

- a static mask of a row of black theater seats, superimposed on the bottom of the screen.  Already done in low-res on a test machine, final art to be produced soon.

- (extra credit) our video-production person is working on creating us a custom door sequence.  It'll be rendered in ProRes 444, with the final few seconds (behind the last door) set as transparent.  That way, we can "leave the theater" and do a skit, the same way the show does, and then go back in with the reverse of that door sequence.

The last part is what I'd like to ask about:  how to best insert three live talking shadow-heads in the lower-right corner of the screen.  (It'll be three humans for us, instead of one human and two robots, but that doesn't matter for technique.)

We do have a camera and green-screen available.  I understand that QLab doesn't do chroma-keying all by itself, so one possibility is to have another program (CamTwist, perhaps?) show the movie and do the keying, and then Syphon all of it into QLab to do the rest.

Another thought was to create a second QLab surface that's 1/4 of the size of the main projection surface, pinned to the lower-right corner, and then use that to show the camera's output.  But once again, we'd need to do a green -> transparent keying in the middle, and I'm not sure how best to accomplish that.

I'd also like advice on what would be the most resource-light way to turn a camera's view into just a straight black shadow.  (Apparently the actual show did it by using a heavily-backlit white curtain to deliberately "blow out" the camera's CCD, and then used luma-keying instead of chroma.  We could try that, but since the camera would be just a few feet backstage, we're trying not to have an obvious bright light back there.  Hopefully a QC effect can be employed instead.)

And finally:  if we stick to 720p projection, do you think a 2014 MBPro (SSD, 16GB RAM, nVidia GeForce 750 2GB dGPU) could handle the workload by itself?

Any and all advice would be greatly appreciated.  Thank you very much!

[Kevin August Landesman]

Hello Dave, 

I would start here https://qlabcookbook.com/1971/02/12/comp/. You can do most of the heavy lifting in quartz composer. But I would suggest at least entertaining the idea of faking it. You could probably build a punch of hand gesture video clips for each person and play them back along with the actors and It would likely be pretty convincing. 

Worth a thought, good luck. 

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[micpool]

Chroma Key Live with QLab will probably achieve what you want

https://www.zachpoff.com/software/chroma-key-live/

Syphon a background Image to it from QLab. Patch your camera to Chroma Key foreground and pick up the chroma key syphon output in a QLab camera cue outputting to your main surface

I'm sat in a dark Auditorium with no green screen so my screenshot just shows a luma key of my FaceTime camera, (with my LX colleagues at their production desk behind)  but the green scorn does work reasonably well for free software. Latency is reasonable too.

Mic

[Wayde Buttimore]

I might not grasp the whole idea here, but if you have a video switcher that can do keying, could output qlab to video switcher input, have live camera with green screen as another input to video switcher, key the live cam input and overlay the qlab input using the video switcher? 

[micpool]

On Tuesday, July 31, 2018 at 12:50:32 AM UTC+1, Dave H. wrote:

> Our small theater group is trying to figure out if we can duplicate Mystery Science Theater 3000's "shadowrama"

> I'd also like advice on what would be the most resource-light way to turn a camera's view into just a straight black shadow.  (Apparently the actual show did it by using a heavily-backlit white curtain to deliberately "blow out" the camera's CCD, and then used luma-keying instead of chroma.  We could try that, but since the camera would be just a few feet backstage, we're trying not to have an obvious bright light back there.  Hopefully a QC effect can be employed instead.)
>

To do shadow effects without a brightly lit background off stage you could look at infra red keying where the backing is lit with invisible infra red light.

Also you can do depth keying with xbox kinect sensor cameras, although I have never got this to work well for a full key on a mac. For producing shadows only though it may give good results.

Mic

[Dave H.]

OK, I will definitely be running some experiments this week, and I'll report back on what I figure out.

Small followup question:  is there any known issue / problem with installing the Legacy Java Environment onto a show computer that doesn't already have it?  Chroma Key Live requires it.  (It's also still 32-bit, which shouldn't matter for another year, but I've contacted the author to ask about the possibility of a 64-bit version.)