Optimised / Proxy / Native Media in FCP X

There are three different types of video media used by Final Cut Pro X:

• Camera native
• Optimized (ProRes 422)
• Proxy (ProRes 422 Proxy)

Camera native media can use a wide variety of codecs, though only one codec is allowed per media file. Codecs include:

• DV
• HDV
• AVCHD
• H.264
• ProRes

Source: Larry Jordan Edit Smarter