Previewing audio

When you preview audio, you control the quality and length of the preview. The audio preview preferences you set do not affect rendering; the quality of audio in rendered video is determined by the output module setting. (See Changing output module settings.)

While previewing audio, After Effects displays clipping signals that indicate when the audio is clipping. Clipping is a distortion that occurs when the audio signal exceeds the maximum level that the audio device allows.

After Effects also displays a Volume Unit (VU) meter that actively displays audio levels during playback. To view the VU meter and levels controls in more detail, increase the height of the Audio palette.


Audio Palette A. Level controls B. Level units C. Audio clipping warning icons D. VU meter E. Audio Options menu F. Level values

You can quickly preview audio in the work area of the Timeline window without rendering frames or wireframes of the video. You can also preview audio synchronized with layer motion. (See Previewing animation.)

To set display options for the Audio palette:

1. In the Audio palette, click the triangle in the upper-right corner and choose Options.
2. In the Audio Options dialog box, select one of the following:
• Decibels to display audio levels as decibels.
• Percentage to display audio levels as a percentage, where 100% equals 0 dB.
3. From the Slider Minimum pop-up menu, select the minimum decibel level you want to display in the Audio palette, and then click OK.

To set preferences for audio preview:

1. Choose Edit > Preferences > Previews (Windows), or After Effects > Preferences > Previews (Mac OS).
2. In the Audio Preview section, type a duration for the audio preview. An audio preview begins at the current-time indicator and continues for the duration you specify here. This option is useful when you are checking short passages of a composition, although you can interrupt an audio preview at any time.
3. Choose an audio sample rate from the first menu.
4. Choose an audio sample size from the second menu.
5. Choose Stereo or Mono playback from the third menu.
6. Click OK.

CD-quality sound is 44.1 KHz, 16-bit stereo. However, to reduce the time and memory required to preview, you may want to choose a lower bit depth and sample rate.

To preview audio:

1. In the Composition window or Timeline window, move the current-time indicator to the time where you want the preview to begin.
2. Choose Composition > Preview > Audio Preview (Here Forward), or press the period key (.) on the numeric keypad.

To preview audio and rendered images:

1. If the Time Controls palette is not open, choose Window > Time Controls. Click the double arrow on the Time Controls tab, as needed, until you see the RAM Preview Options, and then do one of the following:
• If the From Current Time option is selected, move the current-time indicator in the Timeline window to the time at which you want the preview to begin.
• If From Current Time is not selected, set the work area for the area you want to preview.
2. On the Time Controls palette, click the Audio button .
3. If needed, click the Loop button repeatedly to select the preview direction you want: looping from start to finish , single play (forward) , or cycling forward and backward .
4. Click the RAM Preview button  or press 0 on the numeric keypad.

To preview audio in the work area:

Select the layer and press Alt (Windows) or Option (Mac OS) + . (period).

Note: To stop the preview, press the spacebar.

For more information on the work area, see Setting up a work area.