It just cut, crops, etc. If the file has audio, you can adjust volume etc. You can also add audio to a clip, including the audio start and end points within the audio file itself and where it starts and stops in the video. So you can add a mp3 starting at 0:30 of your mp3, and have the audio run from any point to any point in your video. I believe you can even add multiple, overlapping audio tracks, though I don't recall how many.