MIDI contains information about the pitch, velocity, notation and control signals for different musical parameters such as vibration, volume, etc. It also contains information for an instrument to start and stop a specific note. This information is used by the wavetable of the receiving musical device to produce the sound waves. As a result, MIDI is more concise than similar technologies and is asynchronous. The byte is the basic unit of communication for the protocol, which uses 8-bit serial transmission, with one start and one stop bit. Each MIDI command has its own unique sequence of bytes.

One of the most common applications of MIDI is in sequencers, which allow a computer to store, modify, record and play MIDI data. Sequencers use the MIDI format for files because of their smaller size compared to those produced by other popular data formats. MIDI files, however, can only be used with MIDI-compatible software or hardware.