How Do I Convert or Compress the Video I Shot? (Mac Users; iMovie)
Often you may find that the video file you are trying to upload is too large to upload in a timely manner or too large to upload at all. These instructions should help you "compress" it into a much smaller file that will more easily be shareable over the internet.
If the "Welcome to iMovie" window appears, click the "Close" button.
From the file drop-down list, select "New Project"
In the Project Name text box, type a name for your project.
From the Aspect Ratio drop-down list, select the ratio for the display of the video.
Click the " Create" button.
Navigate to the movie import window
From the File drop-down list, select "Import."
Select " Movies"
If the HD Import Setting window appears, click " OK."
Select the video you want to compress.
Click the " Import" button.
Under "New Event," click the imported video.
From the Edit drop-down list, select "Select Entire Clip."
Click and drag the clip to the "Drag media here" space to create a new project pane.
From the Share drop-down list, select "Export using QuickTime."
In the "Save As" text box, type a name for the compressed file.
From the Where drop-down list, select the destination.
From the Use drop-down list, select "Streaming - Medium."
Note: If the file is still too large after exporting, from the Use drop-down list, select " Streaming - Low."