MIDI

MIDI stands for Musical Instrument Digital Interface and refers to the protocols, interfaces, and physical connectors used for audio devices to communicate musically relevant information. MIDI does not transmit audio signals but information used to create them.

Structure of MIDI Information

MIDI transmits data as digital electronic pulses in serial.

Channels

Every MIDI link can carry up to 16 different channels of data. Each device typically "listens" and "speaks" on only one of these channels. This allows MIDI data to be sent along a common cable chain through many devices while targetting different messages for different devices, avoiding the use of patch bays and manually managing loops/sends between devices.

Messages

MIDI sends all its information as messages, which are composed of multiple MIDI bytes. A normal byte is 8-bits, but a MIDI byte is 10-bits, comprised of a start/stop bit, a type bit, and a 7 bit value. The type bit indicates whether the byte is a status byte or data byte. A typical MIDI message is composed of a status byte to indicate what type of message it is followed by 1-2 data bytes. MIDI messages can be one of the 5 types below, which are further broken down.