Changes

The original MIDI (Musical Instrument Digital Interface) protocol was developed in 1983 by Dave Smith and Ikutaro Kakehashi to enable communication between electronic instruments.

Unlike audio protocols MIDI is a set of commands that transmit sound wavesa synthesizer, MIDI carries event messages—instructions about what to playsampler, how or software interprets to play it, and whengenerate sound. These messages includeThe commands are:

*{| class="wikitable"|-! Status Byte (Hex) !! Message Type !! Data Bytes !! Description|-| 0x8 || Note On/Off: Triggers || 2 || Stops a note ; data bytes set the note number (e.g., "play middle C"0–127) and stops itrelease velocity (0–127, often unused).*Velocity: Indicates how hard |-| 0x9 || Note On || 2 || Starts a note is struck ; data bytes are note number (volume or intensity0–127) and velocity (0–127, typically loudness; 0-127acts as Note Off).*Pitch Bend: Adjusts a note’s pitch in real|-time| 0xA || Polyphonic Key Pressure || 2 || Adjusts pressure on one note; data bytes are note number (0–127) and pressure value (0–127).*|-| 0xB || Control Change (CC): Modifies parameters like volume, pan, or modulation || 2 || Changes a controller (e.g., CC#7 for volume, pan, modulation); data bytes are controller number (0–127) and value (0–127).*|-| 0xC || Program Change: || 1 || Switches instrument sounds ; data byte is program number (0–127, e.g., from piano to violin, guitar).|-MIDI doesn’t contain audio | 0xD || Channel Pressure || 1 || Applies pressure to all notes on a channel; databyte is pressure value (0–127).|-| 0xE || Pitch Bend || 2 || Bends pitch; it’s two data bytes form a set of 14-bit value (0–16383, 8192 = no bend).|-| 0xF || System Messages || Varies || System-wide commands that a synthesizer(e.g., samplersync, or software interprets to generate sound. This makes MIDI files tiny compared to audio files—think kilobytes versus megabytesstart/stop); data bytes vary by message type.|}

*Status Byte: Defines the message type (e.g., Note On) and channel (0-15, displayed as 1-16). Each status byte has a '1' as its most significant bit.*Data Bytes: Provide specifics (e.g., note number, velocity). Each data byte has a '0' as its most significant bit.

== Presentation in ACU magazine magazines ==

This Note: In the actual MIDI data bytes, the instrument numbers are 0-127 (zero-indexed). But in user interfaces and documentation, these are typically displayed as 1-128 (one-indexed) to be more intuitive for musicians. General MIDI allowed musicians and composers to create music that would sound reasonably similar on any GM-compliant device, solving the patchwork compatibility issues of early MIDI systems.