MACROMEDIA DIRECTOR MX 2004-USING DIRECTOR, Use Manual, Page: 237 / 500

Compressing internal sounds with Shockwave Audio 237
About Shockwave Audio
Shockwave Audio is a technology that makes sounds smaller and plays them faster from disk or
over the Internet.
Shockwave Audio can compress the size of sounds by a ratio of up to 176:1 and is streamable,
which means Director doesn’t have to load the entire sound into RAM before it begins playing.
Director starts to play the beginning of the sound while the rest of the sound is still streaming
from its source, which can be from a disk or over the Internet. When used properly, the
Shockwave Audio compression and streaming features provide fast playback of high-quality
audio, even for users with relatively slow modem connections to the Internet.
Compression quality in Shockwave Audio
Although Shockwave Audio uses advanced compression technology that alters original sounds as
little as possible, the more a sound is compressed, the more it is changed.
Set the amount of compression by selecting a bit rate setting in any of the Shockwave Audio Xtra
extensions. The bit rate is not related to sampling rates you might have used in other audio
programs. Try compressing the same sound at several different bit rates to see how the
sound changes.
Select the bit rate that is appropriate for the intended delivery system (56K modem, ISDN, CD-
ROM, broadband, hard disk, and so on), the type of movie, and the nature of the sound. Voice-
over sound quality, for example, might not need to be as high as that of music. Test the sound on
several systems to find the right balance between quality and performance.
The more compressed a sound is, the faster it streams. If you select to use a high quality and low
degree of compression, a slow delivery system might not send the data fast enough, which results
in gaps during playback. It’s also important to consider your target audience: for example, using a
lower data rate lets you target a wider audience, but at the expense of audio quality.
Note: Any sound compressed at less than 48 Kbps is converted to monaural.
Compressing internal sounds with Shockwave Audio
Shockwave Audio can compress any internal sounds in a movie. Although internal sounds are not
streamed, compressing them with Shockwave Audio dramatically decreases the size of the sound
data in a movie, shortens the download time from the Internet, and saves disk space.
You can use Shockwave Audio settings to specify compression settings for internal sound cast
members. The selected compression settings apply to all internal sound cast members. You can’t
specify different settings for different cast members.
You can select compression settings at any time, but compression occurs only when the Director
movie is compressed with the Create Projector, Save as Shockwave Movie, or Update Movies
methods. When you create a projector, Director compresses sounds only if the Compressed
option is turned on in the Projector Options dialog box. Compressing sounds can substantially
increase the time required to compress a Director movie. For more information, see
“Creating
projectors” on page 460 .
Note: Shockwave Audio does not compress SWA or MP3 audio sounds.