Apple Final Cut Express HD - Manual (Page 947)

Chapter 66 Choosing Settings and Preferences 947
XI
Real-Time Audio and Video Options
 Real-time Audio Mixing: Enter a number in this field to specify how many audio tracks
can be mixed in real time. The default is 8 tracks, and the maximum is 99. The
maximum number of tracks that can be mixed without having to be rendered is
affected by your computer’s processing capabilities, the number and types of filters
used in your sequence, the data transfer rate of your hard disk, and the amount of
memory available to Final Cut Express HD.
 Audio Playback Quality: This pop-up menu affects the quality of sample rate
conversions (when your audio clips have a different sample rate than the sequence
that contains them) and transitions between rendered and nonrendered sections in
the Timeline.
 Low (faster): This choice yields the best real-time audio performance, but the
lowest sample rate conversion quality. When the playhead moves from rendered to
nonrendered audio segments in the Timeline, there may be an audible click or
distracting shift in levels. For basic editing, this is usually the best choice.
 Medium or High: When you start to do detailed mixing of your audio tracks, you
may want to raise the audio mixing quality to Medium or High. Higher quality
sample rate conversions sound better, but require more processing power and
thus limit the number of simultaneous tracks you can work with in real time. Also,
shifts between rendered and nonrendered audio segments sound smoother.
Important: Final Cut Express HD always uses the highest quality setting (regardless
of what is chosen in the Audio Playback Quality pop-up menu) when rendering,
mixing down audio, editing to tape, printing to video, or exporting audio files.
More About Audio Playback Quality
Sample rate conversion occurs when you use clips with audio sample rates that differ
from the sample rate in your sequence’s settings. If the sample rate of your media
files matches the sample rate of the sequence, this pop-up menu has no effect.
Transitions between rendered and nonrendered portions of audio clips are also
affected by the quality chosen in the Audio Playback Quality pop-up menu. For
example, if you choose Low Quality and you play a partially rendered clip that
contains a reverb, then you won’t hear the tail of the reverb when the playhead
crosses the boundary from a rendered to a nonrendered section of the Timeline.
However, if you choose Medium or High quality, you hear the reverb even when
crossing the render boundary.