FCP X: Delete Generated Media

Final Cut Pro X handles render files and other generated media differently than Final Cut Pro 7. Let me explain.

Definition: Generated Media. Media created by Final Cut. This includes render files, optimized media and proxy media.

FINAL CUT PRO 7

FCP 7 did not have the concept of optimized or proxy media. Yes, AVCHD files would be converted using Log and Transfer to ProRes 422, but, in general, you edited what you shot.

When it comes to render files, Final Cut 7 and Final Cut X both create render files for transitions, titles and effects, including color correction. However, once those files are created, the differences begin.

In Final Cut Pro 7, when you deleted or trimmed a clip to which render files were attached, those render files were immediately deleted. The advantage to this was that you never had render files hanging around not being used, but taking up storage.

While this saves a storage space, it also meant that you were often re-rendering clips that had already been rendered.

FINAL CUT PRO X

FCP X allows creating both optimized and proxy media for a wide variety of reasons, but, in general, they boil down to two:

• Optimized media is faster and easier to edit.
• Proxy media is efficient to edit and takes one-quarter the storage space of optimized media; though with a significant trade-off in image quality.

As a fast estimate, assume that one minute of optimized media takes 1 GB to store, while one minute of proxy media takes about 250 MB to store.

However, FCP X significantly differs from from FCP 7 when it comes to render files.

In FCP X, render files are not deleted when you decide to remove a clip from the Timeline, or trim a portion of a clip, that has already been rendered. Instead, Final Cut Pro X hangs on to render files so that if you add that clip back to the timeline, or readjust the trim to a clip, it instantly reattaches the render files, so that no new rendering needs to be done; assuming there were no changes to the clip since the last time it was used.

NOTE: If Final Cut needs to re-render a clip, any existing render files for the frames being re-rendered are deleted.

WHAT TO DO

Apple made it easy for us to manage generated media using File > Delete Generated Library/Event/Project Files. Final Cut determines which menu to display based upon what you have selected before going to the File menu.

• To delete generated media for an entire Library, select the Library you want to modify, then choose File > Delete Generated Library Files.
• To delete generated media for an Event, select one or more Event(s) you want to modify, then choose File > Delete Generated Event Files.
• To delete generated media for a Project, select the Project you want to modify, then choose File > Delete Generated Project Files.

In all three cases, this dialog appears.

• Delete Unused Render Files. When this option is checked, render files created, but not currently being used by Final Cut, are removed. Any render files that are needed later in the edit are automatically re-generated.
• Delete All Render Files. When this option is checked, all render files are removed. Any render files that are needed later in the edit are automatically re-generated. This sounds scary, but it really isn’t. If you delete render files that are needed by your project, Final Cut automatically re-creates them. All you lose is the time spent re-rendering, and the storage space you picked up when you first deleted the files. Image quality is no different between original render files and re-created render files.
• Delete Optimized Media. When this option is checked, all optimized files for the selected Library/Event/Project are deleted. This means that Final Cut will display and edit camera native media. This option may be grayed out if no optimized files exist or if the camera native files cannot be played directly by Final Cut.
• Delete Prozy Media. When this option is checked, all proxy files are deleted. This option may be grayed out if no proxy files exist.

If you realize, too late, that you should not have deleted either the optimized or proxy files, re-create them by selecting the clips you want to use in the Browser and choose File > Transcode Media.  Again, all you lose is time.

SUMMARY

Give the amount of storage media often required, deleting generated files sounds like a good idea. In general, though, I don’t worry about this, unless I’m desperately short on storage space.

However, I DO delete generated media when archiving a project. There’s no reason to archive files that Final Cut can easily recreate when it needs them in the future.