Chroma Notes

Color-code every note in a sheet music PDF using Boomwhacker colors.

Note	Solfège	Color
C	Do	Red
D	Ré	Orange
E	Mi	Yellow
F	Fa	Lime green
G	Sol	Dark green
A	La	Purple
B	Si	Pink

Powered by oemer for optical music recognition.

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Local CLI

Requirements: Python 3.11+, uv

git clone https://github.com/axelgoris99/chroma-notes
cd chroma-notes
uv sync
uv run chroma-notes input.pdf output.pdf

On first run oemer will download its model checkpoints (~200 MB).

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Web app with Docker

Build and run locally:

docker compose up --build

Open http://localhost:8000, upload a PDF, download the colored result.

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Web app from GHCR (pre-built image)

Pull the image built by GitHub Actions — no local build needed:

docker compose pull && docker compose up -d

The docker-compose.yml already points to ghcr.io/axelgoris99/chroma-notes:latest.

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Updating

git pull
docker compose pull && docker compose up -d

FAQ

"It does not work".

Oof, tough one buddy. Unfortunately many things can go wrong, such as:

• Oemer not recognizing the clef or the note which will lead to the wrong colors
• The queue system messing up if you use the demo version at <chroma.goris.live/>
• The server is busy with other stuff.