Putting It Together
Once you create a killer musical score for your clip and you have the final MIDI or audio file mixed and mastered, combine the soundtrack and the QuickTime movie into a single file. Some sequencers insert the audio into the clip automatically, but QuickTime Player also allows you to add audio layers.
Open your audio file with QuickTime Player and choose Select All from the Edit menu. Copy the Sound Track, then open your video clip and position the diamond slider (which is on the progress bar) to the first frame. Hold the Option key down while you select the Edit menu and the usual Paste command is relabeled Add. This “merges” the soundtrack with the video, rather than “inserts” the audio over blank space. (You can also use the key combination Option+ Command+V.)
Next, select the Save As command and choose the Make Movie Self-Contained option. The file should now be the size of your video clip plus the audio file and might be quite large if you used a CD-quality, 16-bit, 44.1 kHz, stereo soundtrack. This isn’t necessarily a big problem if you plan to distribute your clip on CD-ROM, but the final file should be as small as possible for low-bandwidth delivery on the Internet. Fortunately, QuickTime uses some amazing audio compression schemes to facilitate posting movies on the Web.
The Big Squeeze
The QDesign Music Codec 2 (QDMC2) is QuickTime’s flagship audio compression algorithm and can provide astonishing compression ratios (as much as 50:1) while retaining a great deal of the original audio quality. The resulting movie’s audio bandwidth can be small enough for streaming on the Internet (even at 28.8 Kbps modem speeds), and the sound quality is usually better than comparable MP3 files. QDMC2 is a perceptual codec that uses psychoacoustic principles to achieve dramatic results.
To apply the audio compression, choose Export from the File menu as you did when preparing the low-bandwidth video clip. Select Movie to QuickTime Movie as the Export type and click on Options. The dialog box should look familiar, but this time, click on the Settings button in the Sound section to open a menu of audio compression algorithms. Select the QDesign Music 2 compressor and set the other items in the box to match the bit-depth and sample-rate of your original audio file.
Saving the movie applies the compression to your soundtrack, which usually takes a while to process. Like Sorenson, QDesign sells a Pro version of the codec that gives you access to additional parameters, compresses twice as fast, and is optimized for performance on the new G4 machines. When your computer finishes number crunching, you’ll have a high-quality, low-bandwidth version of your movie complete with original soundtrack that you can post on the Internet for distribution.
Looking Ahead
Apple plans to release OS X with a QuickTime update. The new version is likely to support 24-bit, 96 kHz, multichannel audio; a VST–like plug-in architecture; and latency of less than 10 ms for digital audio throughput. Import and export of Downloadable Samples may also be supported as a way of including custom instruments on the Macintosh and Windows platforms. And look for QuickTime to access the power and flexibility of the MPEG-4 file format.
In any case, QuickTime will continue to be a powerful, flexible, cross-platform technology for delivering multimedia content to users around the globe. Whether on CD, DVD, or the Internet, QuickTime movies always require good soundtracks, and directors are looking for musicians with the necessary technical savvy to produce engaging film scores in this brave new medium. So what are you waiting for? Put that QuickTime demo reel together today!
Neil Leonard III is associate professor at Berklee College of Music. You can hear his saxophone interpretations on the Computer Music Journal’s recent compilation of music from Latin America. Special thanks to Judson Crane, Steve Bannerman, and Steve O’Connell.
Reprinted with
permission from 
Magazine, January, 2001
© 2001, Intertec Publishing, A Primedia Company All Rights Reserved
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