Waves in Wave Tracks

To play back a wave file in DirectMusic, you'll create a Segment out of it. As already mentioned, the DirectMusic Segment file (.sgt) is the basic unit of DirectMusic production. Segments are built from one or more of DirectMusic's various track types, which can make sound (via stand-alone waves and/or DLS instrument triggering) or modify performances (tempo, chord progression, intensity level, etc.). You can create a Segment out of a wave file in DirectMusic Producer. Run DirectMusic Producer and go to File>Import File into Project>Wave File as Segment…. Open a wave file into the program. Building a Segment from a wave file, we get our first look at one of the basic track types in DirectMusic — the Wave Track. Beyond the 32 variation buttons (which we cover in Chapter 3), Wave Tracks play along the sequencer timeline with other Wave Tracks and also with MIDI sequences.

If you look at the size of the Segment file, it is much smaller than the wave file. Here is an important early lesson in content delivery: Segments will know where the wave and sample files that it needs to play are but do not store those files as part of itself. There are several reasons to do this; if several Segments use the same wave data, you do not have to worry about having two copies of it in memory. In addition, if you later want to go back and edit that wave data, you do not have to worry about copying it into several different places. That said, there are various reasons that you might instead want to embed the wave data within the Segment itself — for instance, for the convenience of only having to deliver a single file or file load time considerations.

Files with the extension ".**p" are design-time files. Design-time files are used in DirectMusic Producer for editing purposes and contain information not necessary for run-time use — for instance, a Segment used in a game does not need to include information on what size and position to open editing windows. In addition, design-time files always reference the content they use, even if you specify that content should be embedded. For these reasons, when content is meant to be integrated into a game or a special player, you should save the Segment as a run-time file (either via the per-file right-click menu Runtime Save As… option or the global Runtime Save All Files option from the File menu). When Segments are run-time saved, you will see the .sgt extension, and wave files will similarly have the more expected .wav extension. So to summarize, be sure to save your Segments as design-time (.sgp) files while you are working on them and as run-time files (.sgt) when they are finished and ready for distribution. For more details on content delivery, there is a white paper available on the Microsoft Developer Network web site (msdn.microsoft.com) called "Delivering the Goods: Microsoft DirectMusic File Management Tips."