mixing 3 live video sources and a movie?

Feb 27, 2008 at 2:38pm

mixing 3 live video sources and a movie?

Hi Everyone,

Apologies for another newbie question, but I’m abit stuck. I’m trying to write a simple patch that will allow me to mix three live video feeds (using 2 unibrain firewire cams and one built-in webcam) with one or two movie files, also allowing me to apply various fades between them, effects, math operations etc.

What I’m unclear about is what is the difference between using the jit.lcd-layer vs using multiple jit.gl.videoplanes? And if I want to use the jit.op object to use different math operations for mixing, is there a way to combine these (ie. it’s only got 2 inputs…so how would I apply this for each video source?)

Sorry if these are painfully obvious. I’ve searched the forum but that’s where I ended up with the above questions.

Thanks in advance,

Bill

#36077
Feb 27, 2008 at 7:25pm

Hi Bill
- About the difference between lcd layers and videoplanes- videoplanes are more efficient, as they utilize the gpu. While you’re at it, you could also check the videoplane blend modes, which give you some compositing effects you would otherwise use the operators for. And of course use shaders (look in the “slab helpers” folder, there are example math and compositing patches) instead of jit.ops if you’re heading into opengl land anyway.

- if you do want to use jit.op or other compositing objects- you usually need to chain them: i.e, connect source A and B into the first jit.op, then connect it’s output and source C into the second jit.op, etc. Everything in the computer is binary in the end…

-nadav

#123533
Feb 27, 2008 at 8:02pm

Note that you could also use the 43j-fourwaymix.jxs shader (see
Jitter Tutorial 16) > 4 channels at the same time.
Best

Thierry

—————————————-
Thierry Fournier

http://www.thierryfournier.net

>
> – if you do want to use jit.op or other compositing objects- you
> usually need to chain them: i.e, connect source A and B into the
> first jit.op, then connect it’s output and source C into the second
> jit.op, etc. Everything in the computer is binary in the end…
>
> -nadav
>
>

#123534
Feb 28, 2008 at 12:02am

Hi Everyone,

Thanks for all your replies. The 43j tutorial does seem promising…sorry for missing it in advance (!)…what I’m stuck on now, is how to get the compositing effects from the previous tutorial (42j) combined with this one. I know it must be simple, but I can’t seem to do it. If I could do this, I’d have 75% of the patch there and would just have to put in some basic ‘glitch’ type effects for what I’m attempting, add some audio-triggers, and I’d be done. Any quick simple solutions to this…really sorry if this is obvious…in the beginning, none of this seems obvious ;)

Bill

#123535

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