Play Base Layer Only
The Play Base Layer Only option takes a unique approach to playing back processor-
intensive segments. With this option selected, any segment that requires rendering in
Safe RT mode (in other words, any segment with a red render bar) is restricted to
original media playback, and all effects, including compositing modes, are disabled.
Here are the playback rules for the Play Base Layer Only option:
 Effects that can be played back in real time are played just as they would be in
Safe RT mode.
 If a clip has effects applied, the effects are ignored if they can’t be played in real time.
Only the underlying clip media is displayed.
 Clips with compositing modes applied can never play back in real time, so they are
ignored and only clips on lower-numbered tracks are displayed. Of course, a clip on a
lower-numbered track that has a compositing mode applied will also be ignored.
 Transitions that cannot be played back in real time are disabled, so only the
underlying clip media is displayed.
The Play Base Layer Only option also affects audio playback. When playing over an
unrendered portion of a sequence, no effects are played back. The number of audio
tracks that play depends on whether or not you have selected the Play Base Layer
Only option.
 If selected: The first two tracks of audio play back.
 If unselected: The number of audio tracks that play back is determined by the
number of real-time audio tracks you have set in the General tab of the User
Preferences window.
This video transition is not
shown in the Canvas.
Unrendered audio plays
back without effects.
The clip on track V1 is
shown in the Canvas
without effects.
The clip on V2 is shown in
the Canvas without effects.
628
Part IV
Real Time and Rendering