Editing 24p Video with Final Cut Pro

The excellent quality of 24p video presents a challenge when it comes to editing—the bandwidth and storage space it requires. Editing minimally compressed 24p video directly in Final Cut Pro requires that you have a system with a large, fast hard disk and specialized capture hardware. Even with a properly configured system, you may be able to capture only the video you actually intend to use, not the typical 20 to 100 hours you may have shot.

The typical approach to editing 24p video with Final Cut Pro involves two steps: an offline edit, using compressed 24p clips or downconverted (to standard definition NTSC) and compressed clips, followed by an online edit with recaptured, uncompressed clips.

What Is Downconverted Video?

It is often necessary to use HD video, such as 24p, in systems designed for standard definition (SD) NTSC video. The process of converting HD video to SD video is called downconverting. Most HD VTRs have an option that provides SD video outputs. Several specialized hardware downconverters are also available. See Understanding Aspect Ratios for information about dealing with the aspect ratio differences between the standards when downconverting.

Using a Final Cut Pro System for 24p Offline and Online Editing

Using the same Final Cut Pro system for both offline and online editing makes the process as simple and error-free as possible. The workflow when using the same system for both purposes is outlined below.

  1. Stage 1: Capturing Your 24p Video as Compressed Clips

    Capturing your 24p video using a lower-resolution codec makes it easier to capture and edit the video without running into storage or performance issues.

  2. Stage 2: Performing an Offline Edit of the Clips

    Edit the program using the lower-resolution video clips.

  3. Stage 3: Creating a Duplicate Project That Uses Only Needed Video

    You can use the Final Cut Pro Media Manager to create a duplicate project containing only the video actually used in the program. This is usually much less than half of the originally captured video.

  4. Stage 4: Deleting the Original Clips

    Because the next step is to recapture the video using its native codec, you can delete the original lower-resolution video clips.

  5. Stage 5: Recapturing the Material in the Duplicate Project

    Now that you know exactly which video clips your project needs, you can recapture the video at its native resolution.

Even if your Final Cut Pro system is not configured to edit uncompressed 24p video, it can serve as an offline editor and export a 24 fps EDL to be used by a 24p online editing system. Even better, if your 24p online editing system uses Final Cut Pro, you can simply copy the project from the offline system, allowing you to preserve far more information about the edit than with an EDL alone.

See Using Final Cut Pro as a 24p Online Editor and Using Final Cut Pro as a 24p Offline Editor for more information about each option.

Using 24p Video with Final Cut Pro and Cinema Tools

Final Cut Pro and Cinema Tools give you the ability to handle various situations related to editing 24p video:

  • Importing 24 fps EDLs: Use for performing an online edit of 24p material that has been offlined on another system. See Using Final Cut Pro as a 24p Online Editor for more information.
  • Exporting 24 fps EDLs: Use for performing an offline edit of 24p material with a 24 fps editing timebase. See Using Final Cut Pro as a 24p Offline Editor for more information.
  • Converting an EDL to or from 24 fps: Use for performing an offline edit of 24p material using an NTSC editing timebase or for doing an online edit of 24p material that has been offlined on an NTSC system. See Using Final Cut Pro as a 24p Offline Editor for more information.
  • Removing 2:3:3:2 or 2:3:2:3 pull-down: Use if you are capturing your source clips from a digital video camcorder that applied 2:3:3:2 or 2:3:2:3 pull-down to 24p video. This feature cleanly eliminates the redundant frame fields created by the pull-down, without any recompression, so you can edit at 23.98 fps or 24 fps. See Working with 2:3:3:2 Pull-Down for more information.
  • Adding pull-down: Use to output 23.98 fps video in a format that you can play on an NTSC device, such as an NTSC monitor, and to record it as 29.97 fps video. This feature lets you output 23.98 fps video via FireWire at the NTSC standard of 29.97 fps video. See Pull-Down Patterns You Can Apply to 23.98 fps Video for more information.
  • Creating an audio EDL when using dual system sound: Use if you intend to recapture the audio elsewhere for final processing. See Using Audio EDLs for Dual System Sound for more information.

Using Final Cut Pro as a 24p Online Editor

An important consideration when using Final Cut Pro as your online editor is how to import the offline edit information. When using a separate system as the offline editor, there are three methods you can use to get edit information from the offline system (presented in order of preference):

  • Copy the project: Can be used when a separate Final Cut Pro system is the offline system and you used a 24 fps editing timebase for the offline edit.
  • Import a 24 fps EDL: Can be used when your offline system supports exporting 24 fps EDLs.
  • Import an NTSC EDL: Can be used when your offline system can only edit downconverted NTSC versions of the 24p video and export an NTSC EDL.

Copying the Project

Copying the project from an offline Final Cut Pro system to the online Final Cut Pro system provides not only the edit In and Out point information but also all other information related to the project, such as filter and effects usage. To use this method, you must have edited using a 24 fps timebase on the offline system.

About Importing EDLs

When using non–Final Cut Pro offline systems (or a Final Cut Pro system editing downconverted NTSC versions of the 24p video), you must import an EDL. Final Cut Pro provides both 24 fps EDL import and NTSC–to–24 fps EDL conversion.

Figure. Diagram of a workflow for starting and finishing with 24p video.

Important: Before importing any EDL into Final Cut Pro, make sure that the editing timebase for the sequence is the same frame rate as the EDL. If the frame rate of the EDL is different from the editing timebase of the sequence, the EDL will not be imported correctly.

Importing 24 fps EDLs

Whenever the offline editor is not a Final Cut Pro system, the best way to import information about the offline edit is to provide an EDL. EDLs contain only the basic information about an editing project: the In and Out edit points for the first two video tracks and the first four audio tracks, information for simple transitions, and any notes you have added.

To import a 24 fps EDL into Final Cut Pro
  1. Open an existing Final Cut Pro project or create a new one.

  2. Choose File > Import > EDL.

  3. Configure the Import Options dialog, then click OK.

    Note: If the dialog does not allow you to choose 24 fps as the editing timebase, it’s probably because the Easy Setups included with Cinema Tools are not installed. If they are not installed, reinstall Cinema Tools.

  4. Select the name and location of the EDL file, then click Choose.

A new sequence opens in the project, containing the edits of the EDL, all indicating that the media is offline. The Browser contains a list of the media used in the edit. You can then use the Final Cut Pro Media Manager to capture the clips for the online edit. See the Final Cut Pro documentation for details about capturing clips, importing EDLs, and configuring the Import Options dialog.

Importing NTSC EDLs

You can perform an offline edit of your downconverted 24p video on an NTSC system and export an EDL that can be converted and used by an online Final Cut Pro system. To import an NTSC EDL for use with a 24p project, you first need to convert the NTSC 29.97 fps EDL to 24 fps (or, most often, to 23.98 fps).

Note: Cinema Tools does not support converting PAL EDLs to 24 fps.

See Converting NTSC EDLs to 24 fps for more information. After you have converted the EDL, you can import the 24 fps EDL into Final Cut Pro using the process described in Importing 24 fps EDLs, above.

Using Final Cut Pro as a 24p Offline Editor

Editing 24p HD video generally requires that you first edit it with an offline system. This allows you to choose the actual footage you want to use while working with downconverted or compressed versions of the 24p video.

When the online system also uses Final Cut Pro, it is highly recommended that you perform the offline edit using a 24 fps timebase. This allows you to open the project with the online system and maintain all special settings, effects, and filters—elements that are not included in an EDL.

With online systems other than Final Cut Pro systems, you need to provide a 24 fps EDL from the project.

Cinema Tools provides two tools that make it easier to use Final Cut Pro for 24p offline editing:

  • Reverse Telecine and Conform features: These features are useful when you have captured downconverted versions of the 24p video and want to convert them back to 24 fps.
  • NTSC–to–24 fps EDL conversion: This is useful when you must edit using an NTSC 29.97 fps timebase but need a 23.98 fps or 24 fps EDL.

For offline editing, it is preferred that the 24p video be compressed and captured directly, with no frame rate conversions. This removes the possibility of errors during video and timecode rate conversions and eliminates the need to convert the video’s aspect ratio (see Understanding Aspect Ratios). However, this requires specialized hardware, so the following alternatives using standard downconverted versions of the 24p video have been developed.

Using the Reverse Telecine and Conform Features

24p video is often downconverted to make it easier to use with standard video equipment. Cinema Tools provides tools to convert NTSC or PAL captured clips back to their original 24 fps video, enabling you to edit using a 24 fps timebase:

  • NTSC: Converting 24p video to NTSC video requires using a pull-down method that adds redundant fields, maintaining the action’s original speed (1 second of 24p video equals 1 second of NTSC video). The Reverse Telecine feature removes the pull-down by removing the extra fields and restores the original 24 fps rate. See Reversing the Telecine Pull-Down for information about using the Reverse Telecine feature. If your source clips originated from a special type of DV camcorder that shoots 24p, such as the Panasonic AG-DVX100 camcorder, a simpler form of the Reverse Telecine dialog appears. See Removing 2:3:3:2 or 2:3:2:3 Pull-Down with Cinema Tools for information about reversing the pull-down for clips that originated from a 24p-capable digital video camcorder.
  • PAL: There are several methods of converting 24p video to PAL. The most common is to play the tape 4 percent faster, providing a one-to-one relationship between the 24p and PAL frames, but speeding up the action by 4 percent. Cinema Tools and Final Cut Pro provide a Conform feature that you can use to restore the video back to 24 fps in order to edit it at 24 fps in Final Cut Pro. See Frame Rate Basics for information about frame rate issues.

Converting NTSC EDLs to 24 fps

You may decide to edit the downconverted NTSC version of the 24p video using a standard NTSC 29.97 fps timebase; however, most 24p online editing systems require a 23.98 fps or 24 fps EDL.

Cinema Tools includes a feature that allows you to convert NTSC 29.97 fps EDLs to 23.98 fps or 24 fps. This makes it possible for you to perform an offline edit of your downconverted 24p video on an NTSC system and export an EDL that can be converted and used by an online system.

Note: Cinema Tools does not support converting PAL EDLs to 24 fps.

To convert an NTSC EDL to 24 fps, you need the EDL file to be converted in the CMX 3600 or GVG format. You do not need a Cinema Tools database.

To convert an NTSC EDL to 24 fps
  1. In Cinema Tools, choose File > Export > Converted EDL > 24 FPS from 30 FPS.

  2. In the dialog that appears, locate and choose the EDL file to convert.

  3. In the next dialog, choose the name and location for the new file to be created, then click Save.

The new EDL file is identical to the original, with the exception of the timecode values and effects durations, which have been converted to match the new frame rate.

Important: 24p timecode is always non-drop frame, and the NTSC timecode to be converted must also be non-drop frame. Cinema Tools does not prevent you from converting an NTSC drop frame–based EDL, but instead treats it as if it were non-drop frame. The exported 24 fps EDL will contain errors, and Cinema Tools inserts a warning message into the EDL.

You can now import the 24 fps EDL into Final Cut Pro using the process described in Importing 24 fps EDLs.

Understanding Aspect Ratios

When capturing NTSC or PAL video from 24p sources, you typically choose how to handle the differences in their aspect ratios.

SD video (NTSC or PAL) has a 4:3 (1.33) aspect ratio. This means the picture is 75 percent as tall as it is wide. Many 24p formats use a 16:9 (1.78) aspect ratio that is closer to the common film aspect ratio of 1.85 and is the same as that of the widescreen broadcast HD formats.

Many HD VTRs can downconvert 16:9 video to SD 4:3 video. Final Cut Pro systems not capable of capturing 24p video directly can capture using one of these SD video outputs for editing.

See the Final Cut Pro documentation for detailed information about the options for converting 16:9 video to 4:3 video.