Apple Final Cut Pro 7 - Manual (Page 1435)

Improving Real-Time Audio Performance
You can optimize real-time audio performance in the following ways:
• Render video effects prior to mixing: Playing real-time video effects reduces the number
of audio tracks that can be mixed in real time. While mixing the audio in your program,
you can maximize real-time mixing performance by first rendering all video effects in
your sequence, including all transitions, layered video, and filters. Video and audio
render files are maintained separately, and changes made to the audio levels in your
sequence do not affect the video effects that have already been rendered. For more
information on rendering the video effects in a sequence, see
“Rendering and Video
Processing Settings.”
• Render audio filters: Even though many audio filters play in real time, unrendered filters
can reduce the number of tracks you can mix in real time. The number of audio tracks
you can play without rendering depends on how many filters are applied and how
many audio tracks you’re trying to mix at once.
To increase the number of audio tracks that can be mixed in real time in sequences
with audio filters applied, you can perform item-level rendering on individual audio
items in the Timeline. By rendering audio items with filters individually, audio and pan
levels can continue to be mixed in real time, and you can make level changes without
rerendering. For more information, see
“More About Audio Render Options” and
“Rendering Audio Items in a Sequence.”
• Use the Mixdown command to prevent dropped frames: If you have a complex audio mix
with numerous clips, keyframes, filters, and transitions, the mix may start to affect the
playback of your sequence. Also, if the Audio Playback Quality setting in the General
tab of the User Preferences window is set to High, you may get dropped frames in your
audio. You can use the Mixdown command in the Sequence menu (available by
choosing Sequence > Render Only > Mixdown) to render all the audio tracks in a
sequence, along with their accompanying transitions and filters, into a single render
file. For more information, see
“Using the Mixdown Command.”
Choosing Real-Time Playback Versus Rendering
Here are some practical examples of when you might use real-time playback versus
rendering during the course of editing your movie.
To monitor video or output to tape with perfect playback of all effects in a sequence
(with no dropped frames and full-resolution video)
1 In the RT pop-up menu in the Timeline, choose Safe RT, so there’s a checkmark next to
it.
The Safe RT mode ensures that effects play back at the quality level and frame rate you
specify.
1435 Chapter 84 Using RT Extreme