MIDI (Standard MIDI File)
The universal language of electronic music — tiny files that tell instruments exactly what to play.
| Full name | Standard MIDI File |
| Extension | .midi |
| MIME type | audio/midi |
| Developer | MIDI Manufacturers Association (MMA) |
| Released | 1988 (SMF specification) |
| Type | Audio / Music data |
| Format types | Type 0 (single track), Type 1 (multi-track), Type 2 (multi-pattern) |
| Based on | MIDI 1.0 protocol (1983) |
What is a MIDI file?
MIDI stands for Musical Instrument Digital Interface. A .midi file does not store recorded sound — it stores instructions: which note to play, how loud, for how long, and on which instrument. That makes MIDI files extremely small compared to any audio format that captures actual audio waveforms.
A Standard MIDI File is a structured binary file containing timed MIDI messages — note-on, note-off, pitch bend, control changes, and more. Each message is paired with a timestamp called a delta-time so a player knows exactly when to trigger each event. The file can hold one or more tracks depending on its type. Because it carries performance data rather than sampled audio, the sound you hear depends entirely on the synthesizer or software that plays it back.
History
The MIDI protocol itself was introduced in 1983, the result of a collaboration led by Dave Smith of Sequential Circuits and Ikutaro Kakehashi of Roland, along with engineers from Yamaha, Korg, Kawai, and Oberheim. The Standard MIDI File format was formalized in 1988 by the MIDI Manufacturers Association, partly inspired by Opcode Systems' sequencer work, to let users exchange sequence data across different programs and platforms. After General MIDI was adopted in 1992 — standardizing which instrument sound maps to which program number — SMF files became fully portable across hardware and software.
How it works
A Standard MIDI File starts with a header chunk that identifies the format type (0, 1, or 2), the number of tracks, and the timing resolution in ticks per quarter note. Each track chunk follows, containing a sequence of variable-length delta-time values paired with MIDI events or meta-events like tempo changes and time signatures. Type 0 files pack everything into one track; Type 1 files separate each instrument into its own track, which most DAWs prefer. Type 2 is rarely used today.
What it is used for
- Composing and editing music in a DAW where every note can be adjusted after recording
- Sharing sheet-music-level performances between musicians and software
- Driving hardware synthesizers, sound modules, and digital pianos from a computer
- Ringtones, video game music, and interactive soundtracks where file size matters
How to open it
Most music production software opens MIDI files directly, including GarageBand, Logic Pro, Ableton Live, FL Studio, and Reaper. Media players like Windows Media Player and VLC can also play .midi files using a built-in or system synthesizer.
Pros and cons
Strengths
- Extremely small file size — a full song can be under 100 KB
- Fully editable: change tempo, transpose keys, swap instruments, or fix individual notes
- Works with hardware instruments and software synthesizers alike
- No audio quality loss — it carries instructions, not compressed sound data
Trade-offs
- Sound quality depends on the playback device or synthesizer, not the file itself
- Cannot capture vocals, live instruments, or any recorded audio
- Playback can sound very different across different systems or software
- Rarely used for final distribution — listeners expect actual audio files
Convert MIDI files
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MIDI FAQ
Is a MIDI file an audio file?
Not exactly. A MIDI file stores musical instructions, not recorded sound. You need a synthesizer or software to interpret those instructions and produce audio. The result sounds different depending on what plays it back.
What is the difference between .mid and .midi?
They are the same format. The .mid extension came from older systems limited to three-character extensions. Modern systems use either interchangeably, and the file contents are identical.
Can I convert a MIDI file to MP3 or WAV?
Yes. Software like GarageBand, FL Studio, or free tools like MuseScore can render a MIDI file to audio by playing it through a synthesizer and recording the output. The audio quality depends on the synthesizer you use.
Why do MIDI files sound different on different computers?
Each operating system and app uses its own synthesizer to interpret the MIDI instructions. Windows historically used a low-quality General MIDI synth by default, while professional DAWs use high-quality sample libraries, producing very different results from the same file.