Not all media sources can be imported into iMovie to edit. So you need to know what can be dragged in and can i add iMovie ignorant file to content the produce.
Video formats that iMovie supported:
Tapeless Camcorder(MPEG-2, MPEG-4 and AVCHD) ;
Tape based DV-Standard and HDV (High Definition Video) ;
Part Camera\Mobile Phone video\other video recorder devices(MPEG-1, MEPG-2, MPEG-4, H.264);
MPEG-4 video.
iMovie supported camcorder and device
In the final analysis, limited format supports iMovie. How if you want to edit DVD segments, YouTube FLV Video, QuickTime video, M4V, MOV, MKV, AVI, WMV and other video formats on iMovie. Below i will introduce someway!
How to import Non-Commercial DVD into iMovie
1) Insert DVD.
2) Open Disk Utility.
3) Select the disk and then select "New Image". Save the disk image wherever is convenient, such as the desktop.
4) Once the disk image is written, open iMovie.
5) Mount the new disk image. A "Camera Detected, Scanning Contents" window will appear in iMovie, followed by an import window. You can now import the DVD contents and start editing away.
If you want to import commercial DVD and other videos that refused by iMovie, you need a converter that can rip DVD and convert video to iMovie supported format MPEG-4(MP4). You can try iSkysoft iMedia Converter for Mac, which cost you $49, from our studio. Also handbrake is best choice among free converters. It can convert both DVDs and videos. Here is a guide:
How to use handbrake to rip DVD and convert video on MAC OS X!
After converting, you can import converted videos to iMovie to edit.