Free online BMP to MID converter

What the BMP format is

BMP is a raster image format that stores pixels, not notes, timing, instruments, or other performance data. In music composition, BMP files usually come from scanned printed scores, screenshots of notation software, or bitmap exports made with programs such as Microsoft Paint and older score editors.

A BMP image may show staff lines, clefs, noteheads, rests, dynamics, lyrics, and markings, but those elements are only visual shapes. The file does not provide the structured information required by a sequencer.

What the MID format is

MID, also called MIDI, stores instructions such as note pitch, start time, duration, velocity, channel, program number, tempo, and controller changes. Programs including MuseScore, Steinberg Cubase, Cakewalk, Reaper, and hardware synthesizers can open or play these events.

MIDI files are compact and editable: you can transpose notes, change instruments, quantize timing, and route tracks to virtual or hardware instruments. A MIDI file does not contain recorded audio, so its sound depends on the player or synthesizer.

How to actually convert BMP to MID

1. Prepare the image. Crop away empty margins, desk or scanner backgrounds, and unrelated graphics. Use a straight, high-resolution scan; staff lines and noteheads should be sharply visible. If the OMR program does not accept BMP reliably, convert it to PNG with ImageMagick: magick score.bmp score.png.
2. Recognize the notation. Open the BMP or PNG in Audiveris, an optical music recognition application. Run score recognition and review detected pages, systems, measures, clefs, key signatures, time signatures, tuplets, voices, and lyrics. Export the recognized result as MusicXML.
3. Correct the notation. Open the exported MusicXML file in MuseScore. Compare every measure with the original image and fix incorrect pitches, rhythms, ties, accidentals, voices, tempo markings, and instrument assignments. OMR commonly misreads touching symbols, low-resolution scans, handwriting, and damaged or skewed pages.
4. Export MIDI. In MuseScore, use File → Export, select MIDI or .mid as the output format, choose the destination, and save. Play the result in a MIDI-capable application and inspect timing and track assignments.

For a simple score, you can try the free converter on 101convert.com without installing software, but image-to-MIDI conversion depends on whether its recognition system supports the score layout. A notation editor remains necessary for checking the musical result.

Quality, compatibility, and limitations

There is no lossless direct conversion because BMP contains appearance and MID contains musical interpretation. OMR can identify common printed notation, but it cannot reliably recover every engraving detail, handwritten correction, expressive marking, or intended performance nuance.

Use a scan of at least 300 dpi, preferably in grayscale or black and white with strong contrast. A multi-page score may produce separate MusicXML pages or files; combine and verify them before MIDI export. MIDI preserves note events and basic playback settings, but it does not reproduce the original page layout, engraving, lyrics formatting, or audio recording.

When the BMP contains only a cover, abstract artwork, waveform image, or an illegible score, no dependable MID file can be generated from it. Manual entry in MuseScore or another notation editor is then required.