Users may experience issues in iMovie '09 when attempting to import or play back video. Though iMovie '09 supports many formats, there are many it does not, which could lead to the aforementioned issues. To solve the issue, you may need to convert the incompatible file using QuickTime Pro.
QuickTime Pro ($29.99) can be used to convert video files to formats that are compatible with iMovie '09. For more on QuickTime Pro, check out this page on Apple's Web site. There are also several third-party video conversion applications available not manufactured by Apple.
File formats that work best with iMovie '09 are .DV, .MOV, .MPEG4, .M4V, H.264, and .AIC.
When purchasing your digital video camcorder, be sure to check the file format that the device records to. You can also check out the list of compatible digital video camcorders provided by Apple. Do you have a favorite digital video camcorder or video conversion application? Let us know in the comments!