Sequencer Overview

The MIDI sequencer application (SEQ) consumes standard MIDI type 0 and type 1 byte streams. It applies the MIDI events to the AX SYN application (described in the previous chapter).

MIDI file, sequencer, and synthesizer

For detailed API descriptions, refer to the "Sequencer" pages under "AX Applications" in the Audio section of the Cafe Reference Manual (HTML).

Sequencer features

SEQ exposes logical controls to the user application for runtime manipulation of MIDI sequences.

State control

The user can set one of the following states for any tracks in a MIDI sequence.

State Description
Stop Stops the sequence playback and rewinds each track to the beginning of the track.
Run Starts the sequence playback from the current track position, stops at the end of the track.
Run looped Automatically rewinds and continues playback from the end of the track.
Pause Stops the sequence playback but does not rewind current track position.

Tempo control

The user application can set the current tempo to and retrieve it from any track in a sequence. Tempo is expressed in floating-point BPM (120.0 = 120 BPM).

Volume control

The user application can set the current volume to and retrieve it from any track in a sequence. Volume is expressed in signed fixed point decibels (0x00010000 = 0.1 dB).

Controller event callback interface

The user application may register callbacks for specific MIDI controller events. These events can then be inserted into a MIDI file to notify the user of playback progress.

Revision History

2013-05-08 Automated cleanup pass.
2011-02-21 Initial version.


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