Apple Final Cut Express 4 User Manual
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Chapter 56
Using RT Extreme
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Final Cut Express analyzes a sequence to determine the processor workload required
for playback. Different portions of a sequence may require different amounts of
processing. Final Cut Express breaks the sequence into segments and then indicates
the processor workload for each segment with a colored status bar. For more
information, see “
For example, suppose you edit a DV clip into a sequence. Final Cut Express adds up the
processor “expenses” of reading the media file from your hard disk and decompressing
the DV frames. Because these processor “expenses” are fairly low, the color of the status
bar over that clip in the Timeline indicates that real-time playback is possible.
Now suppose you add a color correction filter to a clip. Playback of this clip is now
more “expensive” for the processor because more calculations must be performed to
display the result. Final Cut Express compares the number of required calculations to
the speed of your computer’s processor. If the processor “expenses” are low enough,
the clip can still be played in real time, even with the additional color correction filter.
Achieving Real-Time Playback When Processor Power Is Exceeded
As you add more effects to a clip, more processing power is required to play that
segment of the sequence. If too many effects are added, Final Cut Express recognizes
that the number of calculations is too “expensive” for the processor, and the color of
the status bar changes to indicate that playback may still be in real time but no longer
at full quality.
To keep your edit session moving and render-free, Final Cut Express has several real-
time playback settings that balance playback quality with a minimum of dropped
frames. For a complete explanation of real-time playback settings, see “
Status bars in the
Timeline indicate the
workload for each
segment; the upper
bar is for video, and the
lower bar is for audio.