SaxHelper

Drop in a PDF, photo or scan of sheet music and get the alto sax fingering for every note, in order. Runs entirely on your own machine.

What it does

• Reads the page. Optical music recognition turns a PDF or image into notes; multi-page PDFs are stitched into one piece.
• Shows the fingering in the printed-chart style — filled keys are the ones you press — plus alternates where they exist (bis Bb, side keys, alt F#).
• Walks the piece note by note, or plays it back with a synth tone, a tempo slider, a metronome click and looping.
• Transposes for soprano, alto, tenor and baritone, and tells you the concert pitch each written note sounds.
• Lets you fix mistakes. Recognition is never perfect, so click any note and nudge it by a semitone or an octave, or open the original page side by side.
• Practice page of warm-ups, scales, arpeggios and patterns, each laid out with every fingering on screen at once.
• Fingering chart for looking up one note, or the whole written range on a single screen, no file needed.

Run it

git clone git@github.com:Aishlia/SaxHelper.git
cd SaxHelper
./run.sh

Needs Python 3.11 or newer. The first run creates .venv and installs the requirements (using uv if you have it), then opens http://localhost:8765. The recognition models download once, about 200 MB, and are cached afterwards.

No file to hand? Hit Try the sample.

Keyboard

Key	Action
space	play / pause
← →	step a note
enter	hear the current note
shift + ↑ ↓	nudge the note a semitone
alt + ↑ ↓	nudge the note an octave

On the practice page, space plays the drill and ← → step through it. On the fingering chart, ← → walk the chromatic scale.

Practice

Thirty drills: long tones and octave slurs, the seven scale keys band music actually asks for, arpeggios, natural minors, patterns, and a set of jazz runs — the bebop dominant scale, 1-2-3-5 patterns, chromatic enclosures, half-whole diminished and a ii–V–I. Pick one and the whole thing is on screen: the notation, then a fingering for every note in order. Play it back at any tempo and the highlight follows along, or click a single diagram to hear that note.

Drills are written pitch, and the header tells you what key that lands in for the horn you picked — written G major sounds B♭ major on an alto.

Reading a diagram

Every key sits roughly where it does on the horn, so you can read the diagram straight onto the instrument. Tick Show key names if you are still learning which key is which.

Fingering chart

Look a note up without a file. Click it on the chromatic staves or walk the range with the arrow keys, and you get the same full-size diagram the song view shows, alternates included.

Switch to Every note for the whole written range on one screen, low B♭ up to altissimo F♯. Notes with a choice show both fingerings side by side — bis B♭ next to side B♭, standard F♯ next to the alternate.

How it works

PDF / image ──► page images ──► recogniser ──► MusicXML ──► note list ──► fingerings
   PyMuPDF                        homr                      score.py     fingerings.py

The backend is FastAPI. Uploads become background jobs so the page can report progress while a scan is being read; MusicXML files skip recognition entirely. The fingering table and the diagram geometry live together in one module, so the picture and the keys it names can never drift apart.

Path	What's in it
backend/app.py	HTTP API, upload handling, job queue
backend/omr.py	page rasterising and the recogniser
backend/score.py	MusicXML → flat note list, multi-page merge
backend/fingerings.py	key layout and the chromatic fingering table
backend/warmups.py	the practice drills, as lists of written pitches
frontend/	the app: score rendering, diagrams, playback
tools/	headless-browser scripts for screenshots and checks

Worth knowing

• Recognition quality follows scan quality. Flat, straight, well-lit pages with clean staff lines work best; handwriting and heavy chord symbols confuse it.
• Fingerings are written pitch, so they are identical on every saxophone. The transposing toggle only changes the concert pitch that is reported.
• Above written F#6 the app falls back to the nearest note an octave down and says so: altissimo has no standard fingering, it varies by player and horn.