sigControl overview

Goto: [ MIDI | Support | Events | Signal ]

The sigControl set of C++ classes handle timing and events to be played in real-time, primarily throught MIDI input and output. The set of control classes described here are useful especially for real-time interaction between the computer and MIDI devices, such as synthesizers and the radio drum.

MIDI Communication

MIDI input and output classes are separated into two categories: (1) private classes to control the hardware/operating system independent coding, and (2) public classes for use in writing programs dealing with MIDI.

Each system configuration must define two classes which will be privately inherited by the classes MidiInPort and MidiOutPort:

MidiInPort_system
MidiOutPort_system

where system is the configuration type that is defined at compilation time for the MIDI classes. These inherited classes can define any necessary functions, but only a uniform set of functions will be available for use in the MidiInPort/MidiOutPort functions regardless of the operating system.

Additional classes may also be used to support the two required system classes. This is usually the case with UNIX systems which combine the input and output devices into one unit; on the other hand, MIDI in/out devices are handled separately in Microsoft's Visual C++ and so does not need any supporting classes.

Here are the general descriptions of the MIDI public classes:

MidiInPort	provides basic MIDI input and handles the opening/closing of devices on the system.
MidiOutPort	provides basic MIDI output and handles the opening/closing of devices on the system.
MidiPort	combines the functionality of MidiInPort and MidiOutPort.
MidiInput	Stores incoming MIDI data into a circular buffer. Able to record Midi commands and timing information to a file.
MidiOutput	defines various MIDI commands such as note-on, program-change, etc. Able to record Midi data passing through the class.
MidiIO	combines the functionality of the classes MidiInput and MidiOutput into one class. Useful for use with MIDI equipment which must have communication in both directions with the computer, for example, the radio drum.

There are also two classes derived from MidiIO for use with particular MIDI devices:

RadioDrum	handles MIDI I/O communication protocol for the Radio Drum.
Synthesizer	handles MIDI I/O communication for synthesizer/computer interaction. Places incoming note on/offs into a circular buffer, and also keeps track of continuous controller messages coming from MIDI in.

Support Classes

There are three main support classes which are utilized by the MIDI communication classes described above:

Timer	Provides for timing control of MIDI events.
MidiMessage	Mostly for use with MIDI input. Contains data fields for one MIDI messages and a timestamp.
CircularBuffer	This class is also primarily used for MIDI input for storing incoming MIDI messages.

Outgoing Events

To be written.

Connection with Signal classes

None yet.

craig@ccrma.stanford.edu