Audio Amplitude Range ?

[hristianm15284498]

Hello. When make an audio amplitude and make a certain effect react to the audio linear(value,xx,xx,yy,yy) how can you find the xx,xx values using trapcode soundkeys ?

[Mathias Moehl]

I recmmend to view the audio amplitude property in the in the graph editor. This does not give you 100% accurate upper and lower bounds, but it is easy to estimate good values.

[Rick Gerard · Accepted solution]

You set the range in sound keys by looking at the waveform display. If you put the top corner right at the top of the highest peak then you'll get a value close to 100 there. If you put the bottom corner of the range sample about half way up then you will get zero for everything below that value. You can then use the graph editor to view the values and see what the looks like. When you are selecting values for the corners you can see a bar on the far right side of sound keys that shows you the range you are working with. You can also set custom values for the top and bottom of the range. The long and short of it is that if you use Sound Keys you do not need to set up an expression. Say that you wanted to rotate a layer from -20º to +20º using sound keys you would set a custom range that matches this for the first range and then adjust the box to suit then just use the pickwhip to point to Range 1 and you're done. That's one of the reasons that sound keys is worth the money.

This example gives you -20 for everything below the bottom of the selected gold frequency volume and +20 for everything above the top selected value.

The only time you really need to use a linear expression is if you want the selected range to drive more than one value. For example, you could use Output 1 to drive rotation directly and then tie opacity to Output 1 to drive opacity by using:

t = thisComp.layer("Sound Keys").effect("Sound Keys")("Output 1")

linear(t, -20, 20, 50, 100)

Personally, I would rather just add another range for opacity and set my own custom values.

The only time I use interpolation methods with audio is when I use the Keyframe Assistant to turn Audio to Keyframes.

Hope this helps.