Apple Final Cut Pro 7 - Manual (Page 1420)

What Are Dropped Frames?
Dropped frames are frames that are unintentionally skipped during playback, either
because the hard disk cannot keep up with the video data rate or because the computer
processor cannot perform all of the applied effects in time. Some real-time playback
modes allow dropped frames, while others require rendering to avoid dropped frames.
Dropped frames during editing are usually tolerable. However, during output, dropped
frames are almost always unacceptable.
Identifying Which Effects Can Play Back in Real Time
The real-time status of effects can be identified in several places:
• Timeline and audio clip item render status bars
• Tooltips in render status bars
• Filter and transition names in boldface type
About Render Status Bars
The presence of a colored status bar in the Timeline indicates that a clip requires some
kind of processing. There are two render status bars above the Timeline ruler. The upper
one is for video and the lower for audio. These render bars indicate which segments of
a sequence will play in real time, the quality of playback, and which segments require
rendering.
Status bars appear near
the top of the Timeline.
1420 Chapter 84 Using RT Extreme