How to convert a .mts file for mac

how do I convert a .mts file for viewing in imovie on a mac?

You don't have to convert it to a different file format. In will open in:
Adobe Flash CS5
Roxio Toast 11
Roxio Popcorn 4
Apple Final Cut Studio
VideoLAN VLC media player

You can try to convert your files to AIC codec since imovie can not recogniaze a mts file unless you import from your camera and it should be recorded at 24/25 fps. I'm using Brorsoft MTS/M2TS Covnerter on my mac. It is fantastic and easy to use. Good choice. Here is the link:http://www.brorsoft.com/mts-converter-mac/index.html.

You can give the software a try and I hope it can help you solve your problem.