Isadora & ‘Randomness’

A user has asked me to show how you can use randomness, or random numbers in Isadora. So thats what this post is about….

I use random numbers ever now and again to trigger random videos during VJ sets, and this is how I do it.

Lets get going.

In a blank Isadora session, import a number of videos, I will import 5.

Create a movie player and a projector, link them up and you should now have this…

If you then click and drag in a ‘Get Media Count; actor, it will update straight away and tell you how many videos you have in your media bin. In my case I have 5. This will be important a bit later on.

Now for the ‘randomness’… select a pulse generator and the random actors, link them together like so;

We need one last actor, thats the ‘counter actor’;

IMPORTANT; we need to change a few parts of the counter actor; they are…

1) Change the MODE from ‘limit’ to ‘wrap’

2) Change the minimum from 0 to 1, as we are always (presumingly) wanted play at least 1 video.

3) Change the maximum from 100 to 5 (or to the number of vids in your media bin at the moment).

We are about done, now wire it up like so (click to open in a bigger window):

You should have the value of the random actor going into the ‘cur value’ which is an abbreviation of ‘current value’, then the trigger of the pulse actor to the ‘add’ or the ‘sub’ trigger. And I have also wired in the ‘Get Media Count’ actor from earlier and connected it to the ‘maximum’.

Why use and wire in the Get Media Count’ actor??? Well now if you import and add anther video it will automatically update the counter and include the video in the probability of being played.

Last stage.

Wire up the output of the Counter actor to the Movie Player like so:

You should now see the videos being changed at a set interval or pulse. Currently it will be pulsing at a rate of 1Hz because this is what the pulse actor is set at. Try altering the value to see different results but be careful it is possible to crash your machine if you go too fast!

Things to think about

  • Try adding motion blur to the patch so you get smoother and more interesting results.
  • Try linking up a keyboard watcher and a tap tempo actor using a key on your keyboard to tap in tempos like so:



2 thoughts on “Isadora & ‘Randomness’

  1. Sorry not sure if this is the best article to post this on but are you aware of anyway to cause Isadora to turn the “visible” field to on, on the movie player and then off again once the clip finishes playing? I want different videos to play when different triggers are set off. So lets say trigger 1 plays I’d like video 1 to play and finish, if trigger 2 activates then video 2 plays. I can do this using an inside range actor, trigger value actor and a movie player. However I can only get each video to play once using the visible field. I can get the field to turn on but not off.



    • Yes you can use a ‘toggle’ actor. This is basically an on/off switch. So you could use the trigger of a movie finishing to turn the movie player off, then maybe a short trigger delay (allowing a new movie to be loaded) and then turn it back on again.


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