Is it the audio that is from your camera? In other words it is the soundtrack to your video clips? Or is it a music or sound effects track?
If it is the soundtrack to the video, please choose a representative clip in your Event, and Right-click/Reveal in Finder. Then in the Finder, right-click this clip and choose Open With.../QuickTime Player. In QuickTime Player, click Command-I to open the Inspector. Tell us everything you see next to the word Format: