Final Cut Pro X: Modify a project’s settings
As your project evolves, you may decide to change its settings.
In most cases, Final Cut Pro manages project settings automatically based on the properties of the first clip you add to a project, but you can change almost all settings of an existing project. If you must modify the project settings, choose video and audio project settings based on how you intend to share your final movie with your audience.
Do one of the following:
Choose Window > Project Properties (or press Command-J).
Click the Inspector button in the toolbar.
In the Project Properties inspector, click the Modify button in the top-right corner.
In the window that appears, change the settings as appropriate.
For a detailed list of all project settings, see Final Cut Pro project settings.