Creates a shape for the waveform of an audio file. Can be applied to any shape or mask path.
- make sure the audio file is in your comp and audible
- create audio keyframes via the Ae menu command Animation->Keyframe Assistant->Convert Audio to Keyframes
- In the "Audio Amplitude Slider" parameter of the expression choose one of the sliders created in step 2
- apply the expression to the shape path property that should become the waveform