[QLab] Quartz composer questions - FPS and Keying

[Pierre-Luc Brunet]

Hello Qlabians,

I have 2 Quartz composer questions for you all.

1-If I take the regular Qlab quarts composition and enable the FPS module, does it display the video FPS as it plays or the screen refresh rate? I've left the setting to "weighted average"

I'm a bit confused because I have 4 videos i've tried with. Here are the details:

a) File: 608x256 - 24 FPS - In Qlab shows at 60.0 ish

b) File: 720p - 24 FPS - In Qlab shows at 40.0 ish

c) File: 1080p - 24 FPS - In Qlab shows at 20.0 ish

d) File: 1920x672 - 59.94 FPS - In Qlab shows at 30.0 ish

Yes there are some variations. For example, sometimes file "d" reaches 60ish but goes back down.

But when I play any of those files in Quicktime player they can play at their original FPS and mostly stay there. It seems to vary a lot more in Qlab. 

I imagine this has a lot to do with the FPS calculation...?

2-Is it possible to make Qlab Quartz composer patch to Luma or choma key a color of one source so we can see a 2nd source. Specifically in this case, we're looking to key white and one of the source would be a live input.

Thank you.

--
Pierre-Luc Brunet
514.209.9393
pierrelu...@gmail.com

[Sander Loonen]

Hello Pierre-Luc

question 1,

I think that the FPS in Quartz Composer shows you the refresh rate of the animation that QC is doing, not info on the actual movie file.

the info on the actual movie file playback is what you get in quicktime.

(this is a guess if there is anyone who actually knows this please correct me)

question 2,

sure, no problem.

import the image that you want to mask to a billboard (or where ever)

add the same image as a mask image and play with a spot color filter to filter out all the colors you don't want to mask.

then get your video input in a other billboard and put it under the mask layer (the chroma image)

for more information on Quartzcomposer

quartzcomposer-dev list list <quartzcom...@lists.apple.com>

most of the stuff going on there goes right over my head, but everybody is very helpful.

have fun,

Sander

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[ShowHow]

hi,Sander Loonen 

I have try your way to do the color key,but doesn't work. 

If it is possible can you give me the example ?

Thanks you .