Effects?

[Lucas Krech]

I would like to be able to make a random opacity effect to move between two pieces of media. This would be easy enough to build as a single movie file except that one of the elements is live video.

In an ideal world QLab would allow me to apply a random effect to a parameter like opacity and walk away. But that is not possible. I could potentially build something in Quartz Composer but that adds another layer of complexity. 

Another thought was to create a separate Cue List (or group cue) that has a looped fire random group containing Fade Cues set to various Opacity levels. 

Any of these options seems rather programming intensive. Any thoughts on simplifying the problem?

Best,

-L

Lucas Krech
Light & Video Artist

www.LucasKrech.com
646.263.8439
Twitter: lucaskrech
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"More light!"
~Johann Wolfgang von Goethe

[Chris Ashworth]

On August 29, 2014 at 11:33:07 AM, Lucas Krech (des...@lucaskrech.com) wrote:

In an ideal world QLab would allow me to apply a random effect to a parameter like opacity and walk away. 

Can you describe in more detail what you mean here? I’m not understanding this sentence.

-C

[Lucas Krech]

In Motion for example I can key frame opacity changes and build a flicker effect one step at a time which is very time consuming. Or I can set the Opacity parameter to randomize and the software takes care of the effect for me. I can adjust settings like rate and high low points but do not need to concern myself with the minutiae of level setting. Does that make sense?

QLab currently only allows the equivalent of the keyframe option. 

-L

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[Chris Ashworth]

Ah, yes, that does make sense, thanks!

[micpool]

You could render your prerecorded media in ProRes 444 with alpha transparency.

Or you could script the opacity of the video using a random number generator,in applescript either directly on the cue if you want jumps,between the levels, or by scripting the level and duration of a fade cue and starting it repeatedly within the script, if you want random fade times as well as random levels.

Mic

[Joshua Langman]

"Another thought was to create a separate Cue List (or group cue) that has a looped fire random group containing Fade Cues set to various Opacity levels."

This sounds to me like by far the easiest and best solution. It shouldn't take too long to generate a ton of fade cues with random opacity values. I frequently do the equivalent of this on lighting consoles to build "random" flicker effects.

[Lucas Krech]

That's not a bad idea at all.

-L

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[Lucas Krech]

I usually use the light board's effects package.

-L

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[Pierre-Luc Brunet]

You can do similar things in after effects as well by using expressions and this becomes a very powerful and invaluable tool in content creation. Many many things can be done but another simple example would be to make a for ever rotating object without having to put any keyframes.

[micpool]

Here's a scripting solution to this. (workspace attached)

It needs 3.1 or later as it needs to run the repeat loop as a separate process

A Script in a Cue called FLICK  changes the opacity of a cue called FTARG

------

tell application id "com.figure53.qlab.3" to tell front workspace

set qnamestore to q name of cue "FLICK"

repeat

set rand1 to (random number from 1 to 2) - 1

if q name of cue "FLICK" is "Stoploop" then exit repeat

set opacity of cue "FTARG" to rand1

delay 0.5

end repeat

set q name of cue "FLICK" to qnamestore

end tell

-------

There is an exit condition built into the script which looks at the Q name of FLICK and if it is "Stoploop" exits the loop and resets the Q name to what it was before.

Therefore in order to  exit the loop you just need a script (which does not have to run in a separate process) to set the q name  of FLICK to "stop loop". In the example workspace the Cue is STOP

------------

tell front workspace

set q name of cue "FLICK" to "Stoploop"

end tell

--------------

There may be a better way of doing this but being able to run  continuously looping  scripts  is potentially useful, as long as there are no unforeseen or undocumented problems.

One thing I found  is; a single press of the ESC key does not terminate any scripts running as a separate process but a double press does.

Stopping a cue with a running script with a double S press does not terminate it.

A brief explanation from Chris in exactly what happens when a script is run as a separate process might be useful.

Mic

On Friday, August 29, 2014 4:33:08 PM UTC+1, Lucas Krech wrote:

[Chris Ashworth]

On September 2, 2014 at 8:14:16 AM, micpool (m...@micpool.com) wrote:

One thing I found  is; a single press of the ESC key does not terminate any scripts running as a separate process but a double press does.

Stopping a cue with a running script with a double S press does not terminate it.

A brief explanation from Chris in exactly what happens when a script is run as a separate process might be useful.

---

A bug; now fixed. Thanks!

-Chris