Get Set
Tempos are stored in a special track, as defined by the MIDI Specification. Using the Tempo track, you must next create a tempo-change MIDI event for each cue that you marked. To start, click on the first marker; this moves the song position pointer and sets the SMPTE numbers to the first cue in the audio, video, and MIDI windows.
Select your score’s region between the current cue and the next one. Then tell the program how many bars and beats you want that region to contain (for example, 16 bars of 4/4 with the first beat of the 17th bar landing exactly on the next cue). Finally, have the sequencer calculate the tempo required to place 16 bars between the two marked SMPTE times.
Most sequencers have a variety of tools for creating tempo maps, letting you program quick changes, accelerandos, and ritards with frame-accurate timing. As long as the markers are locked to specific frames in the movie, you can change the number of beats between cues as needed to produce the desired musical effect. The computer recalculates the tempo settings automatically.
Go for It
Now comes the hard part: actually writing the music. The art and science of composing compelling film scores is outside this article’s scope, but the important thing to consider is how the tempo map you’ve already created affects your themes and phrases. The point of the operation is to produce a musical flow from one cue to the next, whether smooth or abrupt, that supports and enhances the images’ emotional character.
You should use the myriad sequencing tools at your disposal to record the MIDI and audio portions of your score. It doesn’t really matter if you enter the data in step mode, cut and paste from previously produced sequences, or record live to a MIDI metronome, because the tempo map keeps the bars and beats in sync with your video clip’s cues. What does matter is the final format you use to export the score from your sequencer.
If your score relies on samplers, outboard synthesizers, or live recordings of musicians and vocalists, you have to mix and master to a digital audio file format such as WAV, AIFF, or SDII. You can then import the file as a soundtrack into your QuickTime movie and compress it using a variety of algorithms. However, if you want to post your movie on the Internet, you might consider writing exclusively for General MIDI instrumentation. Not only will the resulting movie score be miniscule (offering quick and easy downloads from the Web), but you can take advantage of QuickTime’s built-in MIDI synthesizer.
Getting Soft
 |
|
FIG. 6: QuickTime 4 offers a surprising level of control of its QuickTime Musical Instruments. |
Apple licensed a 2 MB wavetable library from Roland for the QuickTime Musical Instrument set. Based on samples from the Roland Sound Canvas (the de facto standard for General MIDI sounds), the QuickTime library includes the regulation 128 instruments plus seven different drum kits and more than 100 additional patches from Roland’s GS extension to the General MIDI Specification.
Polyphony is limited only by CPU power, and you can include multiple MIDI files in a single movie. QuickTime 4 supports stereo samples and even lets users reassign patch controllers, modify envelopes, and include custom samples for musical instruments and sound effects (see Fig. 6). Overall, it is a powerful, efficient, and flexible synthesizer that can provide composers with a fairly wide audio palette.
Reprinted with
permission from 
Magazine, January, 2001
© 2001, Intertec Publishing, A Primedia Company All Rights Reserved
[an error occurred while processing this directive]
