Final Cut Pro X: Media files and 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 Mac or storage device that contains footage transferred from a camcorder or recording device or created on a 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 storage devices.
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 Mac or storage device. When you modify a clip, you’re not modifying the media file, just the clip’s information in the project. This is known as nondestructive editing, because the changes you make 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 clips in your library or the source media files on your Mac or storage device.
For more information, see Relink clips to media files.