Chapter 6. Adding Audio


Sound is so ubiquitous we hardly notice it. Yet, like the words in captions, it carries a lot of information. In many respects, audio can be the difference between a positive or negative user experience. Sound can set the mood and reinforce the message you are trying to convey. Done right, the user will learn something from your movie. Do it wrong, and you can be guaranteed the user will eject the CD or leave the presentation in a very short time.

Captivate enables you to add voiceover narrations, music, or sound effects to your movie. You can add audio, in the form of WAV and MP3 files, to movie slides in the same manner that you add images and texts. Though the preferred format is MP3, don't let this guide your efforts: Just as in Flash MX 2004, if you use a WAV file it will be converted to the MP3 format when the movie is compiled.

You can also use Captivate to record voice over narrations and add them directly to your slides.

When adding audio to your movie, the key issue will be the traditional tradeoff between sound quality and file size. A 16-bit stereo sound recorded at 44 kHz will be immense yet with quality equal to that of a CD purchased at a record store. For example, a 30-second clip recorded using those settings will weigh in at a hefty 5.3 Mb. Convert the sound to mono and the file size drops to 2.6 Mb. Drop the sample rate from 44 kHz to 11 kHz and the file size drops to 600 Kb with a corresponding drop in quality.

Audio is an area in which the needs of the user and your technical needs intersect. If the user has a 56k dial-up connection, you are going to have to keep things small. If the presentation is being played from a CD or kiosk, these issues don't factor into the equation. Even the user's playback equipment will drive your decisions. Most computer systems use rather low-end equipmentthe cheap speakers or headphones that were part of the computer packageto play back sound. In this case, stereo is more a luxury than a necessity.

Finally, you can't use Captivate to edit recorded audio. Use a third-party application for that purpose. The best you can do in this application is customize how the sound in a slide or movie is output.



Macromedia Captivate for Windows. Visual QuickStart Guide
Macromedia Captivate for Windows. Visual QuickStart Guide
ISBN: 321294173
EAN: N/A
Year: 2003
Pages: 130

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