In this After Effects tutorial, Jake Hering covers how to shorten an audio file to fit whatever length video you're trying to make in Premiere Pro and After Effects.
I already have my audio file uploaded, but if you don't, you can use this file folder right here to click and choose your file and click open. So this is in our waveform, but we need to go to multi-track. So we're going to go multi-track and create a new session. Here, we got all of our tracks and we're going to drag our audio file over to one of these tracks. Place it wherever we want.
And then we're going to go over to our property panels, and we're going to have a remix. We're going to click enable remix, and this will allow us to drag our audio file to whatever length that we want. It will analyze it and clip it in areas to create a seamless transition, so your audio file stays smooth and the cuts are indicated by this zigzag line here. And it blends the pieces together to make it seem cohesive.
Here's the final result: