Convert MP3 to editable MIDI in your browser
Choose an MP3 in Miditap and the converter transcribes its audible pitches into a standard .mid file. The file is decoded, analyzed, and assembled in this browser tab; it is not uploaded to Miditap. Treat the result as an editable draft, especially when the MP3 contains several overlapping instruments.
How to use the converter
- Open the converter and leave Audio to MIDI selected.
- Drop one MP3 file into the page or click the drop area to choose it.
- Wait for transcription to finish, then download the generated
.midfile. - Open the MIDI in a DAW or notation editor and check pitch, timing, note length, and unwanted short notes.
MP3 stores recorded sound, while MIDI stores note events. This is automatic transcription, not a lossless format swap.
A reproducible two-note result
Generic accuracy claims are not useful without a known input. We ran Miditap's checked-in two-note fixture, test-fixtures/two-notes.mp3, through the same browser converter used on the home page. We then parsed the downloaded MIDI with @tonejs/midi and validated its binary structure with the project's validate-midi.py check.
The exported file contained exactly those two note events. The structural validator reported Standard MIDI File format 1, two tracks, 480 ticks per quarter note, 83 bytes, and one end-of-track marker per track.
What this test proves
It proves that this specific build decoded this specific MP3, returned A4 followed by C5, and wrote a structurally valid Standard MIDI File. It also exposes the measured overlap: C5 began at 1.462 seconds while A4 ended at 1.498 seconds, a 0.036-second overlap calculated as 1.498 − 1.462.
What it does not prove
It does not establish an accuracy rate for arbitrary songs. A two-note fixture has no drums, chord stacks, room noise, reverb, or competing instruments. Those inputs create a different transcription problem and must be tested separately. Miditap therefore does not attach a universal percentage to MP3-to-MIDI accuracy.
When the MIDI needs cleanup
Check the result in this order so one fix does not hide another:
- Pitch: remove notes that are clearly unrelated to the audible part and correct octave errors.
- Onsets: align notes that start early or late. Use light quantization only when a grid is appropriate.
- Durations: shorten overlaps that should not be legato and extend notes that were cut off.
- Velocity: even out accidental spikes after the correct notes are in place.
A clear solo melody, vocal, bass line, or single-instrument recording gives the transcriber less ambiguity than a mastered full mix. For a dense song, expect editing rather than a finished arrangement.
Privacy and file handling
Miditap uses Spotify's open-source Basic Pitch TypeScript package inside the page. After the page assets load, browser APIs decode the selected file and the model estimates note events locally. The page then creates the MIDI download in memory. Miditap does not require an account for this workflow.
This describes Miditap's current implementation, not every MP3 to MIDI converter. Other services may upload audio for server-side processing, so read their own data-handling terms before using private recordings.
Sources and test method
- Spotify Basic Pitch TypeScript repository — the transcription library bundled by Miditap.
- The MIDI Association's file-format resources — the authoritative Standard MIDI File reference.
- Miditap fixture and output:
test-fixtures/two-notes.mp3andtest-output/two-notes.mid, parsed locally on October 29, 2026. - Validation command:
python validate-midi.py; note inspection used@tonejs/midifrom this project's locked dependencies.