Apple Final Cut Pro 6 - Manual (Page 1431)

646 Part IV Real Time and Rendering
Rendering is generally required for:
 The use of filters, transitions, generators, or any combination of effects that exceeds
your computer’s real-time playback capabilities.
 High-quality final output. Real-time effects that play back at preview quality must
ultimately be rendered for high-quality video output.
 Video clips using codecs that Final Cut Pro can’t play in real time
 Multiple audio tracks that exceed your real-time playback limit
 Clips with audio effects that require too much processing power
 Some nested sequences, which can include layered Photoshop files
Render Indicators in Final Cut Pro
Final Cut Pro shows you which segments of your sequence need to be rendered by
using render status bars in the Timeline and, in some cases, on individual audio clip
items. A segment is a continuous group of frames within a sequence that require the
same kind of real-time processing.
For example, suppose you have two clips in a sequence. The first clip has a Gaussian
Blur filter applied and the second clip has no effects applied. Final Cut Pro sees two
segments in this sequence: the clip with the Gaussian Blur filter and the clip with no
effect. Adding a transition between the two clips can potentially create a third segment
that has different processing requirements than the other two.
About Render Status Bars in the Timeline
There are two render status bars in the Timeline above the ruler: the upper one is for
video and the lower for audio.
Render bars in the
Timeline: the upper
bar is for video, and the
lower bar is for audio.