Media files and clips
After you import media into your Final Cut Pro library, clips representing the source media files appear in the Browser. A large event may hold many clips.
Media files are the raw materials you use to create your project. A media file is a video, audio, still-image, or graphics file on your hard disk that contains footage transferred from a camcorder or recording device or originally created on your computer. Media files can contain multiple video and audio components. Because media files—especially video files—tend to be quite large, projects that use a lot of footage require one or more high-capacity hard disks.
Clips represent your media, but they are not the media files themselves. The clips in a project simply point to (link to) the source media files on your hard disk. When you modify a clip, you are not modifying the media file, just the clip’s information in the project. This is known as nondestructive editing, because all of the changes and effects you apply to clips in Final Cut Pro never affect the media itself. Trimmed or deleted pieces of clips are removed from your project only, not from the source clips in your library or from the source media files on your hard disk.