Video formats accepted by iMovie include MPEG-2 and AVCHD, DV-Standard and HDV (High Definition Video), QuickTime Movie, MEPG-4. In order to import YouTube video into iMovie, you need to download and convert YouTube video to iMovie compatible format first. It is very easy and fast to download YouTube video and convert YouTube video to iMovie using Clone2Go Video Converter for Mac.
Download YouTube Video
Download the latest version of Video Converter for Mac, install and run it.
Click the icon in the interface of the program. Then you can start to download and convert YouTube videos in the pop-up "Clone2Go YouTube Downloader" window.
Select output format: "MPEG-4 Movie (*.mp4)"
After the downloaded videos are imported into Clone2Go Video Converter Professional, go to the "Output" panel. Click the "Profile" drop-down list to choose "MPEG-4 Movie (*.mp4)" as the output format.
When all settings are done, click the "Convert Now" button to start convert YouTube to iMovie format.
Export the output file to iMovie
Launch iMovie, go to "File > Import > Movies...". Select the converted MP4 video then click "Import".
That's it! Now you can edit your videos in iMovie. Enjoy making your own movies!