Design Center Tutorial
The fundamentals of working with sound in After Effects and Flash
Table of Contents
- Introduction
- The basics of audio in After Effects
- Flash and audio
- An audio controller
- A video sound controller
The basics of audio in After Effects
Audio in After Effects is no different from an Adobe Illustrator® drawing, Adobe Photoshop® image, or video. It is content, and it goes on its own layer in the timeline and appears in the Project panel. The audio file formats that can be imported into After Effects are as follows:
AAC (Advanced Audio Coding): You might know this better as the MPEG-4 format. Designed as the successor to the MP3 format, it is a format used by iTunes.
AU: Originally developed by Sun Microsystems, you commonly find files of this format buried in a Java applet. The sound quality is not good, which tends to explain why this might be the first time you are encountering this format.
AIFF (Audio Interchange File Format): This is the standard for the Mac. For you trivia buffs, here’s a quick way to win a free dinner at your next conference or gathering: AIFF has a sample rate of 22,254.44 KHz. If you do trot this number out during your contest, you are going to be challenged on where it came from. That rate is the original Macintosh sample rate and was based on the horizontal scan rate of the monitor built into the original 128K Mac.
MP3: The official name is Moving Pictures Expert Group Level—Layer-3 Audio, which sort of explains why “MP3” is used. All audio in Flash, regardless of original format, is output to MP3.
Video for Windows: The AVI and WAV formats are used here:- AVI (Audio Video Interleave): This format was developed by Microsoft as a container for both audio and video data.
- WAV (Waveform Audio Format): No, we don’t have a clue where the V comes in. This format, until the rise of MP3, was “King of the Audio World” on the PC.
Note: All audio files used in this tutorial are available in WAV, AIFF, and MP3 formats. We will be adding the file extension to the file name when we ask you to import or export audio.
- Open After Effects and create a new Comp that is 44 seconds in duration.
- Select File > Import. Navigate to the Basic_AE folder in your Chapter 12 Exercise folder that you downloaded. Open it and import the track01.wav file into the Project window.
- Drag the audio file to the timeline and twirl down Audio > Waveform in the timeline. You will notice the only audio property available to you is the audio level and that you can see the audio waveform on the timeline, as shown in Figure 1.
Figure 1: The Audio layer on the Timeline
Tip: Waveform too small? In the timeline, roll your cursor (don’t click and drag) downward through the bottom waveform. When your cursor changes to a double arrow, drag downward, and the waveform will become wider.
- There are a number of ways of previewing the audio just added to the timeline. If you click the Play button in the Time Controls panel or press the spacebar, you won’t hear a thing. The technique you choose to preview audio depends upon what you intend to accomplish. Try each of these:
- To scrub the audio: Press the Ctrl (PC) or Cmd (Mac) key and drag the playback head across the timeline.
- To play a short piece of the sound: Press the . (period) key on your numeric keypad or select one of the options under Composition > Preview > Audio Preview.
- To preview the sound in the work area: Press Alt+. (PC) or Option+. (Mac).
- You can extend the duration of the preview. Open the After Effects Preferences dialog box and select Previews. Change the Duration value to 0:00:08:00 in the Audio Preview section (see Figure 2).
Figure 2: Change the preview duration in the Preferences dialog box.
- After Effects also includes a VU meter that shows you audio clipping, which is a distortion that occurs when the audio signal exceeds the maximum allowed by the device and allows you to change the volume level of the audio track. If you don’t see the Audio panel, select Window > Audio. The Audio panel, shown in Figure 3, contains level controls, the VU meter, and the level units. You can change the level by clicking the Audio Options button on the panel, selecting Options, and changing the Level Units setting to either decibel or percentage and setting the minimum values for the slider. Select the audio file on the timeline, press the 0 key on the numeric keypad, and move a slider up or down. You will notice that as soon as you click the Audio panel, the sound stops. Move the slider to another position and preview the sound again.
Deselect the audio track on the timeline, and you will see the sliders gray out.
Two things will also happen. The first is, if you dragged the slider downward, the volume will be reduced. The second is, if you look at the waveform, that, too, will be reduced toward the line running through the middle of the waveform. That line indicates silence. By moving toward the line, the sound gets fainter.
Move the slider upward, and the sound gets louder and the waveform moves away from the silence line.
The two sliders on either side of the Volume slider control the volume for the individual channel. Drag the right slider downward, and you will notice its waveform changes, the Volume slider moves down, and, if you preview the audio, the affected channel is fainter. You should also notice the Audio Levels properties in the timeline also change.
Figure 3: The Audio panel
Note: The numbers at the bottom of the VU meter are the actual Audio Levels properties in the timeline. Double-click one, make a change, and the audio is changed and the value is shown on the timeline.
If you own Production Studio Premium, which comes with the whole range of audio and video products, you also have Audition installed on your computer. If you want to edit the audio file in Audition right out of After Effects, select the audio file either in the Project panel or on the timeline and select Edit > Edit in Adobe Audition. When you finish making your changes in Audition, save the file, and it will appear in After Effects.
