PDF to MIDI converter
How accurate is turning a sheet music PDF into MIDI?
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Drag & drop a PDF here, or click to choose
PDF exported from notation software, not a photo or a scan
Handwritten manuscript, photo or scan?
The machine only reads PDF exported from notation software. Handwriting, guitar tab, photos and any kind of scan are outside what it can do. Our team transcribes those to MIDI by hand.
Aki's converter reads the printed notes inside a sheet music PDF and exports a MIDI file, so you can open the score in a DAW or notation editor instead of typing every note in by hand. Turning a sheet music PDF into MIDI relies on optical music recognition, a technique that estimates rather than copies, so the result always needs proofreading. The page accepts a PDF exported from notation software (not a photo or a scan), reads its page count right in the browser, then the server recognizes the score and returns a MIDI file.
What is PDF to MIDI conversion?
PDF to MIDI conversion is a machine reading the note symbols printed on a sheet music PDF and rebuilding them as note data a computer can play. The technique is called optical music recognition, usually shortened to OMR. It runs in four stages: find the staff lines in the PDF page and temporarily erase them, classify each remaining symbol as a particular note or marking, assemble those symbols into voices in the right order in time, then export the result as a MIDI file.
Why is this not a file format conversion?
A sheet music PDF contains pictures of notes, not the identity of those notes. To a computer, a page of music and a photograph of a landscape are the same kind of data: pixels. So no format conversion can turn a PDF into MIDI; something has to actually look at the page and make a judgement. That is why the generic "convert anything" sites hand back an empty or broken MIDI file, and it is why this job is priced per page while converting an audio file between formats is a free audio converter that runs in your browser.
Where does music recognition go wrong?
Photos, scans and handwritten manuscript do not work at all: the engine only accepts PDF exported directly from notation software such as Sibelius, MuseScore or Finale, and returns an error immediately on anything else. On files it does accept, real recognition gaps remain: several voices sharing one staff, tuplets and cross-rhythms, repeat marks and jump instructions, and dense two-hand piano writing. Even under the best conditions the output is an estimate to be checked, not an accurate transcription. This tool shortens the typing, it does not replace someone who can read the score.
How is the price worked out?
The unit is the page, not the run: a 3-page file spends 3 pages of the quota, not one turn. The free allowance is 1 pages every 7 days for guests, 5 pages every 7 days once signed in, on a rolling window rather than a calendar-week reset. Anything past the free allowance is billed at 10 Energy per page, only available once signed in, with a hard cap of 9 pages per file even on the paid lane. Splitting a long file into several smaller ones does not get around the cap, because the allowance counts total pages, not total files.
What is the MIDI file actually good for?
A MIDI file opens in most DAWs and notation editors, which makes it a starting point rather than a finished product. Learners use it to hear a piece slowly and practise section by section. Arrangers use it to swap instruments, change key, or pull a single part out and build a new arrangement around it. Teachers use it to put together accompaniment for students quickly. In every case you are editing something that already exists, which is far faster than entering an entire score by hand.
How does this compare to typing it in or working from a recording?
Three routes for three different situations. Typing the score into notation software is perfectly accurate if you can read music, at the cost of hours on a long piece. Machine reading is many times faster but returns a draft with errors in it, which suits you when you want a skeleton and are willing to correct it. And if what you have is a recording rather than a printed page, neither route applies: in that case find the chords from the audio instead, because listening to sound and reading a page are entirely different problems.
Who needs sheet music converted to MIDI?
- Piano and guitar learners who want to hear a piece slowly before practising it
- Arrangers who need a ready note skeleton to change instruments or rebuild an arrangement
- Music teachers preparing accompaniment and practice material for students
- Anyone with an old notation-software PDF who wants it turned into an editable, remixable MIDI file
- Composers checking a score by having a machine play it back
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