Adobe After Effects CS4 - Manual (Page 204)

198 USING AFTER EFFECTS CS4
Views and previews
Last updated 12/21/2009
Standard previews play at a speed as close to the speed of real time as possible. However, for complex compositions,
the speed of the preview may be much less than real-time speed.
❖ Click the Play button in the Preview panel, or press the spacebar.
Manually preview (scrub) video and audio
• To manually preview (scrub) video in the Timeline panel or go to a specific frame, drag the current-time indicator.
• To scrub audio in the Timeline panel, Ctrl+Alt-drag (Windows) or Command+Option-drag (Mac OS) the current-
time indicator.
• To scrub audio and video in the Timeline panel, Ctrl-drag (Windows) or Command-drag (Mac OS) the current-
time indicator.
If you stop moving the current-time indicator while keeping the mouse button depressed, a short section of audio
loops.
To manually preview (scrub) only the frames that are already rendered and cached into the RAM cache, press the
Caps Lock key before dragging the current-time indicator. This prevents After Effects from trying to render other
frames when you drag over or past them. This technique is useful when you want to manually preview some frames that
you rendered using RAM preview settings that used an option to skip every other frame.
Audio panel options
During previews, the Audio panel volume unit (VU) meter actively displays audio volume levels. At the top of the VU
meter, signals indicate when the audio is clipping—a distortion that occurs when the audio signal exceeds the
maximum level that the audio device allows.
To view the VU meter and levels controls in more detail, increase the height of the Audio panel.
Audio panel
A. VU meter B. Level controls C. Level units D. Audio panel menu E. Level values
Choose Options in the Audio panel menu to specify the following options:
Units Choose whether to display audio levels in decibels or in percentages. 100% equals 0 decibels (0 dB).
Slider Minimum The minimum audio level to display in the Audio panel.
Move the current-time indicator
The most basic way of previewing frames is to manually preview by moving or dragging the current-time indicator.
A
C B
E
D