What Is a MIDI File and How Does It Work?

For Artists

Photo of JC Sanchez, Founder & CEO of Orphiq

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Founder & CEO, Orphiq

What Is a MIDI File and How Does It Work?
What Is a MIDI File and How Does It Work?

A MIDI file stores musical performance data, not audio. It records which notes were played, when they started, how hard they were hit, and how long they lasted. A MIDI file contains instructions that tell a virtual instrument what to play. Change the instrument, and the same MIDI file sounds completely different.

Artists often confuse MIDI with audio because both live inside a DAW session. But they are fundamentally different. An audio file is a recording of sound waves. A MIDI file is a recipe. It tells a plugin what to cook, but the sound depends entirely on which plugin you feed it to. This distinction makes MIDI one of the most flexible tools in modern production. If you are getting started with recording and production, Music Production Basics covers the full workflow from DAW setup through mastering.

What MIDI Data Actually Contains

A MIDI file is small. Often just a few kilobytes. It holds no audio, no samples, and no waveforms. Here is what it does contain.

Data Type

What It Records

Why It Matters

Note On/Off

Which note starts and stops

Defines the melody, chords, and rhythm

Velocity

How hard the note was played (0-127)

Controls volume and expression per note

Duration

How long the note is held

Shapes phrasing and feel

Pitch bend

Smooth pitch changes between notes

Adds expression, guitar bends, vocal slides

Control change

Knob and fader movements (mod wheel, sustain pedal)

Automates plugin parameters in real time

Program change

Which instrument patch to load

Switches sounds mid-performance

Every piece of this data is editable after recording. That is the core advantage.

If a note is wrong, you move it. If the velocity is too hot, you drag it down. If the timing is slightly ahead of the beat, you nudge it back. Try doing that with a recorded vocal take.

How Big a MIDI File Actually Gets

"A few kilobytes" is vague, so here are measured files. Each one was written to the Standard MIDI File spec, then read back with a MIDI parser to confirm the note count and duration.

What it holds

Note count

File type

Size on disk

Four-bar chord progression, four chords

16

Type 0, 1 track

183 bytes

Four-bar drum groove, 16th hats plus kick and snare

80

Type 0, 1 track

690 bytes

Three-minute arrangement: keys, bass, drums, lead, pad

3,600

Type 1, 6 tracks

30 KB

The byte math behind those numbers is simple. The file header is 14 bytes. Each track chunk adds another 8 bytes of overhead. Every note costs a note-on and a note-off, each carrying its own timing value, which works out to about 8 bytes per note in the three-minute file above.

Now compare that last row to audio. Three minutes of 44.1 kHz, 16-bit stereo WAV runs 31.7 MB, about a thousand times larger than the 30 KB MIDI file describing the same performance. That gap is why MIDI moves through email, Discord, and shared drives without anyone thinking about file size.

How MIDI Works in Your DAW

When you create a software instrument track in your DAW (as opposed to an audio track), that track expects MIDI input. You can input MIDI three ways: play it on a MIDI keyboard, draw it into the piano roll with your mouse, or import a MIDI file.

The DAW routes the MIDI data to whatever virtual instrument is loaded on that track. A piano plugin turns the data into piano sound. Load a synth on the same track and the identical MIDI data now plays as a synth line. The performance is identical. The sound is entirely different.

This is why producers use MIDI for nearly everything except vocals, live guitar, and other acoustic instruments that need to be recorded as audio. Drums, bass, synths, strings, pads, and keys are almost always MIDI in a modern session because MIDI lets you change your mind.

Committed to a bass sound three weeks ago? Swap the plugin. The notes and timing stay put.

MIDI File Types: 0, 1, and 2

Open a .mid file in a hex editor and the first 14 bytes tell you what kind of file it is. The Standard MIDI File spec defines a header chunk carrying three numbers: the format, the number of tracks, and the division, which sets how time is measured and is normally the number of ticks in a quarter note. The format number is the one that changes what happens when you import the file.

Type

What the spec calls it

What that means in your DAW

Where you run into it

Type 0

A single multi-channel track

Every part merged onto one track, separated only by MIDI channel, so 16 parts maximum

Ableton Live's only export format, and the merge option in Pro Tools, Cubase, and REAPER

Type 1

One or more simultaneous tracks

Parts can remain on separate tracks, all playing together, with the tempo map stored in the first track

Logic Pro's standard export, the only type Studio One writes, and the multitrack option elsewhere

Type 2

One or more sequentially independent single-track patterns

Separate patterns that are not meant to play at the same time

Almost nowhere. The MIDI Association says it never caught on

Two practical rules fall out of this. First, converting a Type 1 file down to Type 0 drops information, and converting back does not restore it, so keep the Type 1 version as your master.

Second, if a MIDI file lands in your session at 120 bpm in 4/4 when the part clearly is not, check whether the file carries tempo and time signature at all. The spec names those exact values as the assumed defaults when a file does not specify them.

MIDI Support Across DAWs

Most music-production DAWs handle MIDI files, but not in the same way, and the differences show up the moment you send a file to someone on another platform. Here is what each maker's own documentation says. If you are still choosing a platform, the beginner DAW comparison covers the wider decision.

DAW

MIDI file export

Quirk worth knowing

Ableton Live

Type 0 only, and one clip at a time

Imports Type 0, 1, and 2 files ending in .mid or .smf. Rename a .midi file to .mid or the import fails

Logic Pro

Type 1 from Export > Selection as MIDI File

Type 0 export stays off until you tick a box in Settings > General > Project Handling

Pro Tools

Type 0 or Type 1, picked in the Export MIDI Settings dialog

Muted tracks are left out, and playlists flatten, so dozens of clips come back as one

Cubase

Type 1, or Type 0 with one checkbox

You set the export resolution yourself, anywhere from 24 to 960 PPQ

Studio One

Type 1 only, never Type 0

File > Save As with a .mid name is the export that keeps the tempo map and song markers. Program changes are not captured

FL Studio

Per pattern from the Piano roll menu

A project-wide export first needs the "Prepare for MIDI export" macro, which swaps channels for MIDI Out plugins

REAPER

Type 0 merged, or Type 1 multitrack, with options to embed tempo and markers

MIDI lives inside the .RPP project file by default, so there is no .mid until you export one

GarageBand (Mac)

Export Song to Disk offers AAC, MP3, AIFF, or WAVE

Import works fine: drag a .mid file onto a software instrument track

Timing Resolution Is Not the Same Everywhere

Most MIDI files store time as ticks per quarter note, and that number is written into the header, which can instead specify SMPTE timing. DAWs do not agree on it. Ableton Live exports at 96 ppq and shifts every event onto that grid, which is why an exported groove can land slightly differently than it sounded. REAPER creates new MIDI items at 960 ticks per quarter note.

Cubase lets you pick anything from 24 to 960. Pro Tools displays 960 ppq in Bars|Beats and runs an internal resolution of 960,000 ppq.

If your timing feels wrong after a round trip through someone else's DAW, resolution is usually the reason. Steinberg's own documentation says to choose the export resolution based on the application that will read the file, because some cannot handle every value.

MIDI Files Outside Your DAW

MIDI files (.mid) are a universal format. You can export MIDI from one DAW and import it into another. You can share MIDI drum patterns, chord progressions, or full arrangements with collaborators regardless of which DAW they use.

This portability makes MIDI files useful for several practical scenarios.

Collaboration. Send a MIDI file of your chord progression to a producer. They load it into their DAW, assign their own sounds, and build on top of your ideas. No need to be on the same platform.

MIDI packs. Producers sell and share libraries of MIDI patterns: chord progressions, drum grooves, bass lines, melodies. These are starting points, not finished songs. You load them, change the sounds, edit the notes, and build your own arrangement around them.

Notation and sheet music. MIDI files can be imported into notation software like MuseScore or Sibelius and converted to sheet music. The conversion is imperfect (MIDI does not store dynamics or articulation markings the way notation does), but it is a fast starting point for artists building arrangements for live performance or session work.

Does a MIDI File Have Copyright Protection?

This question comes up more than you would expect. A MIDI file that represents an original composition is protected by copyright the same way a lead sheet or audio recording is. The copyright is in the composition (the melody, harmony, and arrangement), not in the format.

If you write an original chord progression and melody as MIDI data in your DAW, that composition is yours. If you download a MIDI file of someone else's song and use it in your production, the same copyright rules apply as they would for sampling audio. The format does not change the law.

MIDI packs sold commercially typically come with licenses that allow you to use the patterns in your own productions. Read the license. Some restrict you from reselling the MIDI files themselves. Others allow unlimited commercial use of songs made with the patterns. The distinction matters.

Common MIDI Mistakes

Quantizing everything to the grid. MIDI lets you snap every note to perfect time. But perfect time sounds mechanical. Leave some human timing in your parts, especially drums and keys. Quantize to 80% instead of 100%, or manually adjust notes that feel stiff.

Ignoring velocity. Every note at the same velocity sounds like a robot playing your part. Vary the velocity to create dynamics. Accented beats hit harder. Ghost notes are softer. This is what separates a programmed drum part from one that feels played.

Overcomplicating simple parts. MIDI makes it easy to add 16 layers of harmonies and counter-melodies. Restraint is harder than complexity. If a simple two-note bass line serves the song, adding five more notes serves your ego.

Frequently Asked Questions

Can I convert a MIDI file to audio?

Yes. Load the MIDI file onto a software instrument track in your DAW, then bounce or export that track as a WAV or MP3. The audio quality depends entirely on the virtual instrument you use.

Are MIDI files royalty-free?

The format itself has no royalty implications. If the MIDI data represents an original composition, that composition has copyright. MIDI packs are typically licensed for commercial use, but read the specific terms.

Can I open a MIDI file without a DAW?

Yes. Free tools like MuseScore, the Online Sequencer web app, or most media players can open .mid files. The playback will use generic sounds, so it will not sound like a finished production.

What is the difference between a Type 0 and Type 1 MIDI file?

Type 0 merges every part onto one track, separated by MIDI channel. Type 1 can keep parts on separate tracks, which is what you want for collaboration. Converting Type 1 to Type 0 drops information permanently.

Read Next:

From File to Finished Release:

MIDI files turn into tracks, tracks turn into releases, and releases need a plan. Orphiq helps you build the release timeline around your music and keep your team working from the same plan, so the creative work does not get buried in logistics.

Ready for more creativity and less busywork?