Apple Final Cut Pro 5 - Manual (Page 1316)

Chapter 23 Using RT Extreme 529
III
Real-Time Audio Mixing in Final Cut Pro
Final Cut Pro can mix and play back multiple audio tracks in a sequence in real time,
even while you make adjustments to levels, stereo pan, and audio filters. The number
of tracks that can be played back while being mixed and filtered depends on your
computer’s capabilities and settings, including:
 Your computer’s processor speed
 The seek time and sustained transfer rate of your hard disk
 The amount of RAM available to Final Cut Pro
 The Audio Playback Quality setting in the General tab of User Preferences
Note: For information on this setting, see Volume IV, Chapter 22, “Choosing Settings
and Preferences.”
Different filters and transitions affect real-time playback in varying degrees. If
Final Cut Pro can’t mix all the tracks in a sequence in real time, you hear a series of
beeps indicating that part or all of your sequence must be rendered before being
output as a final mix.
∏
Tip: You can turn these beeps off by disabling the Beep When Playing Unrendered
Audio option in the Playback Control tab of System Settings.
Calculating the Number of Tracks Played Back in Real Time
The number of tracks Final Cut Pro attempts to mix in real time is determined by the
Real-time Audio Mixing setting in the General tab of the User Preferences window. The
number of real-time tracks you can play back is largely dependent upon your hardware,
so performance will vary from system to system. Increasing the number of tracks in this
setting doesn’t mean they’ll all play.
Important: If the number of tracks is set too high, you may have dropped frames
during playback.
To determine the number of tracks your system can play back in real time:
1 Add a video clip with a typical data rate for your working environment to your sequence.
2 Add 16 or more audio clips at the same point in time as your video clip.
3 Choose Final Cut Pro > User Preferences, then click the General tab.
4 In the Real-time Audio Mixing field, enter the number of tracks in the sequence.
5 Make sure the checkbox labeled “Report dropped frames during playback” is selected.
6 Click OK.