Using the OfflineRT Format in Final Cut Pro

The OfflineRT format uses video settings optimized for offline-quality, low-resolution editing and maximum real-time effects in Final Cut Pro. Final Cut Pro includes two basic varieties of OfflineRT settings, one for standard definition and one for high definition formats.

In both cases, the video frames are stored progressively. The frame rate of the OfflineRT format should always match the frame rate of your original video, or it will be impossible to accurately reingest your original footage for online editing.

These factors greatly reduce the data rate of the video, although they also lower the quality. You should use this format only for offline editing, with the intention of reingesting your video at full quality and full resolution for your online edit.

About Offline Editing with Apple ProRes

Many of the offline editing techniques described in this chapter also apply to other video codecs and formats. In particular, the Apple ProRes 422 (Proxy) and Apple ProRes 422 (LT) codecs provide high-quality video for offline edits of HD and digital cinema formats. For more information about the Apple ProRes format, see Professional Formats and Workflows, available in Final Cut Pro Help.

Keep the following points in mind when considering the Apple ProRes format for an offline edit:

  • Offline editing with Apple ProRes is done at the original frame size, frame rate, and aspect ratio. This is particularly advantageous for projects that involve graphics or compositing. All versions of Apple ProRes support every popular video resolution, including 720 x 486, 720 x 576, 960 x 720, 1280 x 720, 1280 x 1080, 1440 x 1080, 1920 x 1080, 2048 x 1024, and 2048 x 1152. This allows you to perform your offline edit at the same resolution as your source.

  • Editing with Apple ProRes at the same resolution as your source requires higher data rates and file sizes. For example, the SD data rate of the Apple ProRes 422 (Proxy) codec is approximately three times that of the same project in the OfflineRT format, which is 320 x 240, less than 1/4 the pixels of SD. Therefore, if data storage is the most important issue, OfflineRT would still be the lowest data rate format for the offline edit.

Setting Up and Capturing Media to an OfflineRT Format

Before you capture, you need to choose an appropriate OfflineRT format for offline-quality editing in Final Cut Pro.

To prepare your project for capturing media to an OfflineRT format
  • Choose an OfflineRT Easy Setup that corresponds to the standard or your original footage (NTSC or PAL) and frame rate.

OfflineRT Easy Setups are named with the following conventions.

  • Video standard: NTSC or PAL
  • Frame rate: The frame rate is included in the name of an OfflineRT Easy Setup when nonstandard frame rates are used, such as 23.98 fps for NTSC video.
  • Anamorphic: Choose an anamorphic Easy Setup if you shot your original footage with an anamorphic lens or the anamorphic (16:9) setting selected on your camcorder.

For information about choosing an Easy Setup, see Connecting DV Video Equipment.

Capturing or Recompressing Media to an OfflineRT Format

Once you’ve selected the appropriate Easy Setup, you can capture OfflineRT clips using your camcorder or deck. For more information about capturing, see Capturing Video from Tape.

When your system is set up correctly, you can log and capture using device control as usual. During capturing, video is transcoded from its original format to the OfflineRT format and written to your scratch disk.

Alternatively, you can capture your footage at full quality and full resolution and then transcode, or recompress it, to the appropriate OfflineRT format using the Media Manager. For more information, see Example: Recompressing Media Files for Editing on a Portable Computer.

Editing with Low-Resolution OfflineRT Media Files

You edit your OfflineRT sequence just as you would if you had ingested your footage at full quality and full resolution.

Using Full-Resolution Graphics in a Low-Resolution, OfflineRT Sequence

Even though your OfflineRT sequence is set to small image dimensions, as you edit, you can import and use your full-resolution still graphics in your low-resolution project. Therefore, it’s not necessary to create your graphics with two different dimensions for offline and online editing.

When you edit graphics into your sequence that are larger than that sequence’s frame size, Final Cut Pro automatically resizes them to fit. For example, while working at offline resolution, your sequence frame size is 320 x 240. If you edit in a still graphic that was created with a frame size of 720 x 480, Final Cut Pro sets the Scale property of this graphic (shown in the Motion tab of the Viewer) to 50 percent to fit the sequence’s 320 x 240 frame size. Generators used in your sequence always inherit the dimensions of the sequence they are in.

When you create your full-resolution sequence for online editing, the dimensions of your graphics and generators are automatically set to the proper dimensions.