4 Replies Latest reply on Aug 4, 2016 5:56 PM by Roei Tzoref

Audio Reaction Formulae Assistance

Hi, could someone please provide their perspective and heightened knowledge on the matter.

I saw a video tutorial on a person using the reactions making audio react to scale of a shape, so it would bounce out.

I was inspired on that and thought how cool glow intensity would look like so I took a standard image and animated it, its an image with a art drawn background of the ocean underneath and so I added a glow to some of it's elements such as the fish and the bubbles etc then while the audio plays certain elements react to the height of the frequency, but till today I have lost the formula I had used to make every glow particle react to certain frequencies but the main question is: How do I make it that the glow intensity on certain elements transition slowly instead of looking like its being switched on and off "spazztically" like switching off a light and then switching it on again, I would like to make it look more professional and make it look like there is an on-off transition in about 1sec so instead of it stop glowing instantly rather transition the intensity from eg. 75% till 0% over 1sec at a frequency of " x "

• 1. Re: Audio Reaction Formulae Assistance

I don't Know if I may post the video here of how it looks but here is the OneDrive link: Microsoft OneDrive - Access files anywhere. Create docs with free Office Online.

and here is the OneDrive link to the .aep or the "After Effects Project"

• 2. Re: Audio Reaction Formulae Assistance

I am far from an expressions expert but no geniuses are here yet so here goes

if you want to convert/change/modify the values that you get from the audio amplitude you need an expression. there are many ways to do this.  one of the basics expressions is linear. as explained here:After Effects Tutorial | Audio Keyframes - YouTube like the tutorial illustrates - this is one way to do it: you set the expression on the BOTH CHANNELS stopwatch: first you look for the range of the both channels amplitude - just look when it's the highest and when it's the lowest - you can use the graph editor to see the curve to find it easily, or look at the waveform and see when it's the highest - I think in your case the your audio is 0 - low, 30 - high. so we will go with that. alt click on the stop watch of Both Channels and set this expression linear(value, 0, 30, 0, 100) this means that if will convert the 0 (low) value of the amplitude and the 30 (high) value of the amplitude to 0 and 100 (but you can specify any value you want for it to convert to).  after that you can pickwhip the parameter you want to be affected by this (for example glow radius I think will be good) to the both channels stopwatch and there you have it.

this is another expression by the Dancing-with-Scripts-Master Dan Ebberts to deal with audio to keyframes: just copy the expression he typed down there to the value you want to affect, and set the parameters in the expression box on what is high and low in your audio amplitude, and then set the factor for it to multiply your value.

and here is another way:

How to Convert Audio to Keyframes in Adobe After Effects

more geeky information in here under interpolation methods:

Expression language in After Effects

• 3. Re: Audio Reaction Formulae Assistance

Yes the link you provided from the motion script website is what I attempted firstly with the expression of linear(value,20,30,0,100)

on one of the audio keyframes but the transition seems a bit erratic, as you see on the site: http://motionscript.com/design-guide/basic-audio.html  the scale jumps very quickly, but is it possible to transition more slowly using an average of some sort?

It currently looks like: linear(value,20,30,0,100)

but could you assist me to make it transition slower?

Thank you very much for also replying to the post, I appreciate it a lot.

• 4. Re: Audio Reaction Formulae Assistance

I edited my comment again in a related post. it is now more accurate so maybe this could help you:

about the transition. you could try the smooth expression (information is on the resources page) and apply it to the Both Channels value, and use linear on the glow value like this: linear (pickwhip to the Both Channels stopwatch, number, number, number, number). you can also look for assistance in the after effects expressions forum, and also creativecow expressions forum.