As noted by many early adopters of iMovie ’11 (part of the iLife ’11 suite), the software still does not support the import of AVCHD (.mts) files from a number of camcorders. As described by Apple Discussions poster boombass:
“After installing, I tried to import some loose .mts files, but they are greyed out. Some brief exploring turned up nothing to help.”
As a workaround, some users have resorted to use of VoltaicHD, a software tool that can import and convert various AVCHD files into formats compatible with iMovie ’11. The clips can then be imported and edited using iMovie.
Update: Apple has now published a knowledge base article that addresses this issue and offers a method for accessing the AVCHD files. It states:
“Some camcorders that record multiple formats require extra steps to import both formats into iMovie ’09 and iMovie ’11. To view and import AVCHD clips from your multi-format camcorder in iMovie, MP4/iFrame footage should be imported, preferably backed up, and then deleted from your camcorder. After all MP4/iFrame clips have been deleted from your camcorder, disconnect the camcorder from your computer and then reconnect it back again. The AVCHD clips should appear in the iMovie Import window.”