iMovie for Mac: Rotate a clip
You can rotate a clip before or after adding it to your movie.
Rotate a video clip or photo
To show the cropping controls, click the Cropping button.
Do one of the following:
Rotate the clip clockwise: Click the Rotate Clockwise button on the right side of the cropping controls.
Rotate the clip counterclockwise: Click the Rotate Counterclockwise button on the right side of the cropping controls.
To apply the change, click the Apply button in the cropping controls.
To reset all crop and rotation adjustments, click the Reset button.