MIDI track splitter
Break a multi-track .mid file into one file per track — or one per MIDI channel — with the tempo, time signature and key signature copied into each part so it plays back correctly on its own. Runs entirely in your browser; nothing is uploaded.
About this tool
A multi-track MIDI file is a container: one header, then a stack of track
chunks, one per part, plus a conductor track at the front holding the tempo,
time signature and key signature for the whole piece. This tool takes that
container apart and writes each part back out as a complete .mid file of its
own — so you can import just the bass line into a project, hand one player their
part, or feed a single melody to a tool that only accepts one track at a time.
Paste the file as base64 or hex and choose how it should be cut:
- One file per track — the usual cut for a Format 1 file exported by a DAW or notation program, where each instrument already has its own track chunk.
- One file per MIDI channel — every event on channel 3 is gathered from every track into one part. This is the right cut for files that put several instruments in one track, and it is what a Format 0 file (which has only a single track) is always split by.
The thing naive splitters get wrong is the conductor data. Tempo and time signature normally live in track 0 only, so a part pulled out on its own plays back at the MIDI default — 120 BPM in 4/4 — no matter what the original said. Copy tempo, time and key signature into every part is on by default and fixes exactly that; events a part already carried are never duplicated. Turn it off if you are re-importing the parts into a project that supplies its own tempo map.
Each part is written as Format 0 (one merged track — a genuinely single-track file) or Format 1 (the conductor data kept as its own first track, with the part second). Either way, every note-on, note-off, velocity, controller, pitch bend and program change is carried through at its original tick, and the source division — ticks per quarter note, or SMPTE timecode — is preserved, so nothing is re-gridded or quantised.
Filenames are built from what is actually in the file: the track name meta event
when there is one, otherwise the General MIDI instrument implied by the part's
program change (channel 10 becomes the drum kit), so an import shows
part-02-bass.mid rather than track2.mid.
Worked example
Splitting a small three-track file — a conductor track at 120 BPM in 4/4, a Piano part on channel 1 with two notes, and a Bass part on channel 2 with one — with every default left alone gives two files:
| # | Part | From | Instrument | Notes | Length | File |
|---|---|---|---|---|---|---|
| 2 | Piano | track 2 · ch 1 | Acoustic Grand Piano | 2 | 1.00 s | part-02-piano.mid |
| 3 | Bass | track 3 · ch 2 | Electric Bass (finger) | 1 | 1.00 s | part-03-bass.mid |
The conductor track itself is not exported, because it holds no notes — its tempo and 4/4 time signature were copied into both parts instead, so each one opens at 120 BPM on its own. Every "Try:" button above runs a real example; switch Return to Just the list of parts to see the same table without producing any files, which is the quick way to look inside a file first.
Limits and edge cases
- The decoded file may be up to 4 MiB, and one split may produce at most
64 files. Use the parts selector (
1,3-5) to work through a bigger file in batches. - Format 0 input has a single track, so a track split would just hand back the input; it is cut by channel automatically and the summary says so.
- Format 2 files hold independent sequences rather than parallel parts, so each track is exported as-is and no conductor data is shared between them.
- SMPTE timecode files are supported: the division is copied unchanged and part lengths are computed from the frame rate rather than a tempo map.
- Parts with no notes — the conductor track, muted placeholders — are skipped unless you untick Skip parts with no notes.
- Nothing is uploaded. The whole split runs as WebAssembly inside this tab, so unreleased material never leaves your machine.
FAQ
Will the split parts still play at the right tempo?
Yes, as long as Copy tempo, time and key signature into every part is left on (it is by default). Tempo, time signature, key signature and SMPTE offset are collected from the conductor track — and from anywhere else in the file that carries them — and written into each part, so a part opened on its own plays at the original tempo instead of the MIDI default of 120 BPM. If a part already contained one of those events, it is kept and not duplicated.
Should I split by track or by channel?
Split by track when your file came out of a DAW or notation program with one instrument per track — that is the normal Format 1 layout, and it preserves the names you already gave each part. Split by channel when several instruments share a track (common in older files, game music and General MIDI karaoke files), or whenever you specifically want one file per MIDI channel. A Format 0 file only has one track, so it is always cut by channel.
What is the difference between Format 0 and Format 1 output?
Format 0 merges the conductor data and the part into a single track — one genuinely single-track file, which is what most importers and simple players expect. Format 1 keeps the conductor data as its own first track with the part second, which is closer to how DAWs organise a project and makes the tempo map easy to see and edit separately. The notes are identical either way.
Why paste base64 or hex instead of uploading the .mid file?
This page runs the whole split as WebAssembly in your browser tab and takes its
input as text, which keeps the tool a pure, link-shareable function — every
field can be pre-filled from the URL. To get the text, run
base64 -w0 song.mid (or xxd -p song.mid | tr -d '\n' for hex) and paste the
result. Encoding is auto-detected, so you rarely need to touch the encoding
selector.
Does splitting change my notes, timing or velocities?
No. Note positions are stored in ticks — musical units relative to the file's division — and every event is copied to its original tick in the output. The division itself is preserved too, so nothing is quantised, re-gridded or rounded. Swing, humanised timing, velocity dynamics, controller curves and pitch bends all come through exactly as they went in.
How are the output files named?
Each name is <prefix>-<number>-<part name>.mid, for example
part-02-bass.mid. The number is the source track number (or the MIDI channel,
when splitting by channel), and the name comes from the track name meta event,
falling back to the General MIDI instrument of the part's program change, or to
the channel number. Channel 10 is named as the drum kit, per the General MIDI
convention. Change the prefix to anything you like; duplicates get a numeric
suffix so no two files collide.
Can I export only some of the parts?
Yes — put the ones you want in Only these parts as numbers and ranges, such
as 1,3-5. The numbers are track numbers when splitting by track (track 1 is
the first chunk in the file) and MIDI channel numbers 1-16 when splitting by
channel. Leave the field empty to export everything. Setting Return to
Just the list of parts first is the easiest way to see which numbers you want.
Developer & Automation Access
Run it from the terminal
Same engine as this page, headless — via the gizza CLI:
gizza tool midi-track-splitter "4d546864000000060001000300604d54726b0000002000ff0309436f6e647563746f7200ff510307a12000ff58040402180800ff2f004d54726b0000002000ff03055069616e6f00c00000903c4060903c00009040466090400000ff2f004d54726b0000001800ff03044261737300c12100912464814091240000ff2f00"New to the CLI? Get gizza →
Open it by URL
Pre-fill and auto-run this tool with query parameters — the names match the API/CLI:
https://gizza.ai/tools/midi-track-splitter/?input=4d546864000000060001000300604d54726b0000002000ff0309436f6e647563746f7200ff510307a12000ff58040402180800ff2f004d54726b0000002000ff03055069616e6f00c00000903c4060903c00009040466090400000ff2f004d54726b0000001800ff03044261737300c12100912464814091240000ff2f00&encoding=auto&split_by=track&include_conductor=true&output_format=format-0&skip_empty=true&select=leave%20empty%20for%20every%20part&filename_prefix=part&output=filesMachine-readable descriptor: tool.json — title + parameters JSON Schema for agents.