Random Motion Linked to an Audio Control

[Darby Edelen]

If you’re trying to link the Audio Level to the Z values of the layers that should be fairly straightforward. I think the only thing you need to think about is how you want it to be carried out, do you want only one instance of the sound that takes an average Z value of all the layers? Do you want multiple instances of the sound that react to specific layers? The end result you’re looking for will determine how to carry it out.

[Twelvizm]

I wanted to have multiple instances controlling multiple audio files.

That was each object has it’s own sound it makes while it moves.

[Darby Edelen]

In that case you’d have something like this applied to the Audio Levels of the sound file (assuming that your audio file is directly above the associated moving layer in the timeline):

loudMax = -5; //The loudest that the audio file will ever be in dB
loudMin = -40; // The quietest that the audio file will ever be in dB
close = -200; // The smallest Z value expected
far = 1400; // The largest Z value expected
distance = thisComp.layer(index+1).transform.position[2]; //The Z value of the layer beneath this one

linear(distance, close, far, loudMax, loudMin); //As the Z-position of the layer below this one varies from ‘close’ to ‘far’ vary the return value from ‘loudMax’ to ‘loudMin’

Unless there’s something more complicated you’re looking for this should do it.

[Twelvizm]

It’s throwing a error at “transform”

Thanks for waling me through this. I’m starting to understand the logic, but I still have no vocabulary. This next semester I’m takng a actionscripting class. Then I’ll be able to ween myself from asking simple rooted questions.

[Twelvizm]

I used the picWhip to select the exact variable distance =

thisComp.layer(“file_name”).position[2];

And now I get an error for
“Expression must be for dimension 2 not 1”

[Dan Ebberts]

Try changing the last line to this:

lev = linear(distance, close, far, loudMax, loudMin);
[lev, lev]

Dan

[Darby Edelen]

Ah yes, I forgot that Audio Levels are stored in a 2 dimensional array (like 2D position data) the first entry in the array is the left channel’s level and the second is the right channels so the expression should actually be:

loudMax = -5; //The loudest that the audio file will ever be in dB
loudMin = -80; // The quietest that the audio file will ever be in dB
close = -200; // The smallest Z value expected
far = 1400; // The largest Z value expected
distance = thisComp.layer(index+1).transform.position[2]; //The Z value of the layer beneath this one

myLevel = linear(distance, close, far, loudMax, loudMin); //As the Z-position of the layer below this one varies from ‘close’ to ‘far’ vary the return value from ‘loudMax’ to ‘loudMin’

[myLevel, myLevel]

Thanks for catching my error, this is what I get for not testing my expression in AE (; This will give the audio the same level in the left and right stereo channels. You could improve upon this by lowering the amount coming out of the left channel if the ‘bug’ is on the right side of the screen:

myWidth = thisComp.width; //The largest X value visible in the Comp window
balance = thisComp.layer(index+1).transform.position[0]; //The X value of the layer below this one
leftMult = linear(balance, 0, myWidth, 1, 2);//As the bug moves to the right we increase the left multiplier to 10 (dB are measured in negative values… 2 * -5 = -10 = quieter)

rightMult = linear(balance, 0, myWidth, 2, 1);//As the bug moves to the right we decrease the right multiplier to 1 (1 * -5 = -5 = louder)

myLeftLevel = myLevel * leftMult;
myRightLevel = myLevel * rightMult;

[myLeftLevel, myRightLevel];

This would go just above the final statement [myLevel, myLevel] in the previous expression (which would now be deleted). Here is the final expression, and I promise I tested this one! I even tweaked some of the numbers to my liking, you can mess with them more:

loudMax = -5; //The loudest that the audio file will ever be in dB
loudMin = -80; // The quietest that the audio file will ever be in dB
close = -200; // The smallest Z value expected
far = 1400; // The largest Z value expected
distance = thisComp.layer(index+1).transform.position[2]; //The Z value of the layer beneath this one

myLevel = linear(distance, close, far, loudMax, loudMin);

myWidth = thisComp.width;

balance = thisComp.layer(index+1).transform.position[0];

leftMult = linear(balance, 0, myWidth, 1, 2);

rightMult = linear(balance, 0, myWidth, 2, 1);

myLeftLevel = myLevel * leftMult;
myRightLevel = myLevel * rightMult;

[myLeftLevel, myRightLevel];

[Twelvizm]

Thanks for the follow up and adding a little more functionality. The panning will be even better. I’m locked out rendering right now, but I’ll check it out tomorrow.

[Twelvizm]

(SORRY, RENDERING RIGHT NOW ##CAPS##)

IT WORKS GREAT.

BUT

I FORGOT TO METION THAT I WANTED IT TO BE IN RELATION TO A ANIMATED CAMERA. IS THERE ANY WAY TO PULL THAT OFF?

[Darby Edelen]

I was having so much fun playing around with this expression that I decided to render out a sample of the (newly altered) expression in action. =) Thanks for inspiring me:

https://video.google.com/videoplay?docid=-1751789126326910391

The effect is most dramatic in the middle portion.

Here’s the [final?] code used:

loudMax = -12; //The loudest that the audio file will ever be in dB
loudMin = -20; // The quietest that the audio file will ever be in dB
close = -200; // The smallest Z value expected
far = 1400; // The largest Z value expected
distance = thisComp.layer(index+1).transform.position[2]; //The Z value of the layer beneath this one

myLevel = linear(distance, close, far, loudMax, loudMin);

myWidth = thisComp.width;

//The following section is new and required for the change to the ‘balance’ equation:
motionLayer = thisComp.layer(index+1);
halfWidth = motionLayer.width / 2;
halfHeight = motionLayer.height / 2;

balance = motionLayer.toComp([halfWidth,halfHeight])[0]; //This is a new form of this equation that converts the XYZ coords of the layer to screen X coordinates for more realistic panning

leftMult = linear(balance, 0, myWidth, 1, 2);

rightMult = linear(balance, 0, myWidth, 2, 1);

myLeftLevel = myLevel * leftMult;
myRightLevel = myLevel * rightMult;

[myLeftLevel, myRightLevel];