Apple Final Cut Pro 7 - Manual (Page 1418)

Being able to see your sequence play back in real time, regardless of the quality, is often
more important than seeing full-quality video. By default, Final Cut Pro attempts to
calculate video at full quality. However, it’s fairly easy to exceed your computer’s ability
to calculate effects in real time and at full quality.
To maintain your creative pace, avoid rendering, and maximize performance, Final Cut Pro
provides several real-time playback modes, such as Safe RT and Unlimited RT.
To learn about where you can change real-time playback settings, see “Locations for
Changing Real-Time Playback Settings.”
To read detailed explanations about each real-time playback mode, see “About Real-Time
Playback Options.”
Real-Time Playback Versus Rendering
For most stages of editing, reduced playback quality is more acceptable than losing the
ability to play back effects in real time. Toward the end of a project, during the “finishing”
stages such as color correction and output, you can choose to render at full quality to
ensure the best results. For more information, see
“Rendering and Video Processing
Settings.”
Note: Final Cut Pro always displays real-time previews using 8-bit processing.
How Real-Time Processing Works
Consider a clip placed in a sequence. Even when no effects are applied to the clip,
Final Cut Pro and your computer must do a certain amount of work to play back the
media file associated with that clip: the hard drive must be able to read the frames of
video as fast as they need to be displayed, and the computer processor must decode
each video frame into uncompressed pixels that are then shown on your computer display.
In the past, even the most expensive computers could barely achieve the required hard
disk and processor speeds. Editors often had to install specialized video cards that could
provide the necessary processing power for playback. Today, personal computers can
easily achieve video playback and still have a lot of processing power left to spare.
How Final Cut Pro Calculates Processor Workload
You can process your video footage in a remarkable number of ways: by adding video
filters, adding motion effects such as scaling and rotation, making speed changes, adding
transitions between clips, and compositing multiple video layers. All of these effects are
really just mathematical operations performed on the pixels of your video. The more
effects you add to a clip, the more operations are required to display the results.
1418 Chapter 84 Using RT Extreme