How to convert a piano recording to MIDI
The conversion itself is one upload. Everything that decides whether the result is worth having happens before and after it, and most of it takes a couple of minutes.
Step 1. Check the recording is the right kind
Automatic transcription reads pitches out of sound. What helps and what hurts follows from that directly.
| Works well | Solo piano, recorded reasonably close, with the notes clearly audible. A phone recording of an acoustic piano in a normal room is usually fine. |
|---|---|
| Works less well | Heavy reverb or a large hall, where each note smears into the next. Very quiet passages buried in room noise. Strong compression, which flattens the dynamics before anything can read them. |
| Does not work | Piano with vocals, strings, drums or a backing track over it. The transcription will try to turn the other instruments into piano notes, and the result is not worth editing. |
If your piano is part of a full mix, separate the stems first with a stem-splitting tool and transcribe the piano stem on its own. Expect the separation to leave artefacts that show up as extra notes.
Step 2. Trim before you upload, not after
Cut off applause, talking, count-ins and long silences. They cost processing time and can only confuse the result. If you only want one section, upload only that section — a shorter, cleaner file gives a better transcription than a long one you intend to crop later.
You do not need to convert the file format yourself. Damper converts whatever you send before processing, so MP3, WAV, FLAC, M4A and the audio track of a video all arrive at the same place. The formats page lists the limits.
Step 3. Upload and listen before you commit
Upload the file and wait. A four-minute piece takes about two minutes. When it finishes you can play the transcription back against the original in the browser, which is the fastest way to judge it: you will hear a wrong note long before you would spot it in a piano roll.
What comes back is a single standard MIDI file, type 0, one track, containing the notes, their timing, a velocity for each one and the sustain pedal as CC64. No sheet music, no MusicXML.
Step 4. Fix these first in your DAW
No automatic transcription is finished when it lands. In our experience these are the things worth ten minutes, in this order:
- Extra notes in the bass. Low notes have dense overtones, and transcription sometimes hears a harmonic as a separate key. Scan the bottom octave first.
- Missed notes inside fast runs. Where notes are close together some get merged. Compare against the audio at half speed.
- Pedal changes that sit slightly early or late. Nudge rather than redraw; the shape is usually right even when a change is a fraction off.
- The tempo map, if you need notation. A recording of a human performance does not sit on a grid. For a score you will need to set a tempo track or quantise; for a production where the MIDI drives a sampler, leaving the timing as played is usually what you want.
What not to expect
A transcription is a reading of a performance, not a copy of the score the pianist read. It will not know that a passage is written in three voices, it will not split the hands into two staves, and it will not write fingering or dynamics markings. If the goal is printed sheet music rather than an editable performance, you will be doing notation work in a score editor afterwards regardless of which tool produced the MIDI.
Transcribe a recording