Official MIDI Specifications

MIDI 1.0

MIDI 1.0 is a ubiquitous protocol that allows different musical instruments and devices to communicate with each other using digital messages. MIDI 1.0 was first published in 1983, the outcome of collaboration between various manufacturers.

The first version of MIDI 1.0 defined a core data format for messages and a serial transport using 5 pin DIN connectors. MIDI 1.0 has been expanded with many features and reached far beyind the dreams of the original designers.

MIDI 1.0 remains a core vital standard, and continues to evolve. MIDI 1.0 specifications available here also continue to be crucial documents as foundational components of MIDI 2.0.
The following changes/additions became part of the MIDI 1.0 Specification after the "96.1" publication and should be consulted to have a current understanding of MIDI technology.
The General MIDI Specifications (GM 1, GM 2, and GM Lite) define specific features and behaviors for compliant MIDI devices. In particular, files created for GM devices all use the same GM Sound Set which helps provide for more consistant playback among different MIDI devices.

Note: The GM 1 specification was superceded in 1999 by General MIDI 2 which added support for additional features and capabilities which had become commonly available since GM 1 devices first appeared. However, GM 1 remains a popular format and is still commonly used for music distributed in Standard MIDI File (*.mid) format.

MIDI logonobgrd copyMIDI, the Musical Instrument Digital Interface, was established as a hardware and software specification which would make it possible to exchange information (musical notes, program changes, expression control, etc.) between different musical instruments or other devices such as sequencers, computers, lighting controllers, mixers, etc. This ability to transmit and receive data was originally conceived for live performances, although subsequent developments have had enormous impact in recording studios, audio and video production, and composition environments.

This latest revision of the basic MIDI 1.0 specification includes the original definition of the core layout of MIDI 1.0 messages, the classic MIDI 1.0 tranport of 5 pin DIN connectors, and several core additions collected together in 1996. Other additions to MIDI 1.0 since 1996 are available as separate downloads.
M1-100-UM MIDI Polyphonic Expression v1.1
(replaces rp53 MIDI Polyphonic Expression)

This specification is designed for MIDI controllers that allow the performer to vary the pitch and timbre of individual notes while playing polyphonically. In many of these controllers, pitch is expressed by lateral motion on a continuous playing surface, while individual timbre changes are expressed by varying pressure, or moving fingers towards and away from the player.
The MPE specification defines a MMA/AMEI Recommended Practice for hardware and software manufacturers to communicate multidimensional control data between MIDI controller instruments, synthesizers, digital audio workstations, and other products, using MIDI 1.0 messages.
The specification describes a recommended way of using individual MIDI Channels to achieve per-note control without requiring Mono Mode (which would restrict polyphony to a maximum of 16 notes). This enables richer communication between increasingly expressive MIDI hardware and software.
M1-100-UM MIDI Polyphonic Expression is a version 1.1 update which replaces the previous rp53 version 1.0. Version 1.1 has significant editorial improvements for clarity but has no technical design changes.