|Microsoft DirectX 9.0|
Audio data flows through the performance in the form of messages. Performance messages are similar to MIDI messages but contain more information and a greater variety of information. A message could contain information about a musical note, a waveform, or a controller change. It might even contain text for a display of lyrics.
Most applications don't deal directly with messages, which are generated by tracks when a segment is playing. However, it is possible for an application to insert messages into the performance. It is also possible to intercept messages by using plug-in components called tools.
Messages are also used for notifications. Applications can request that an event be signaled whenever certain points in the performance are reached—for example, on every beat of the music. Information about the event is contained in a performance message.