Saving video to an iPad from Google Drive was not possible until I found a solution courtesy of one of our IT people, @kenwestphal.
Collaborating with multiple students on different iPads or taking video with an iPhone or iPod was a difficult task because the Google Drive app only allowed downloading of images for use in iMovie. Using the G Drive (Green) app now allows for videos to be imported into iMovie once the video is uploaded to a student's or teacher's Google Drive account.
If students are recording video using an Android device, the video will need to be converted before G Drive will import it into iMovie on the iPad. We use Any Video Converter.
G Drive (Green) App
Google Drive App
View how it works! Don't forget to have students log out of the G Drive app.