Before starting work at your project you can set the aspect ratio used for your output video. The aspect ratio of an image is its displayed width divided by its height (usually expressed as "x:y"). You can read more detailed information on the aspect ratio here. In everyday life you will not need all the theoretical knowledge on the aspect ration and its details.
When you start a new project and place an image or video file to the Timeline you'll be asked if you'd like to keep the aspect ratio of the file for the whole project.
If you want to change the project's aspect ratio, we'd recommend that you use the following simple rules while choosing the necessary aspect for your output video.
To set the aspect ratio values use the Aspect Ratio option of the Edit section of the Top Menu and select one of the options:
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