Osu2Jam

In-browser osu!mania (7K) to O2Jam (.ojn / .ojm) beatmap converter built with Nuxt 4 and WebAssembly.

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Features

• Multi-Format Ingestion: Drag & drop support for .osz, .zip, .7z, .rar, or raw beatmap folders.
• 7K Mania Parsing: Maps notes (rice & long notes), measures, BPM, and timing points to the O2Jam specification.
• Client-Side Audio Transcoding: In-browser audio conversion to OJM using WebAssembly FFmpeg with audio delay/offset compensation.
• Cover & Thumbnail Support: Extraction and processing of beatmap background images into O2Jam BMP format.
• Dynamic Level Ratings: Converts osu! star ratings into O2Jam difficulty levels with color-coded tier badges.
• Metadata Editor: Slide-over panel to customize Song Title, Artist, Creator, Song ID, and Level before downloading.
• Batch Export: Convert and export selected songs or all uploaded beatmaps into a single .zip archive.
• Modern Dark UI: Powered by Nuxt 4, Nuxt UI, and Tailwind CSS.

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Tech Stack

• Framework: Nuxt 4 / Vue 3 / TypeScript
• UI & Styling: Nuxt UI / Tailwind CSS
• Audio Processing: @ffmpeg/ffmpeg (WebAssembly)
• Beatmap Parsing: osu-parsers, osu-classes, osu-mania-stable
• Archive Handling: @zip.js/zip.js

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Getting Started

Prerequisites

• Node.js (v20+ recommended)
• pnpm (corepack enable pnpm)

Installation

# Clone the repository
git clone https://github.com/KenZync/osu2jam.git

# Navigate into directory
cd osu2jam

# Install dependencies
pnpm install

Development Server

pnpm dev

Open http://localhost:3000 in your browser.

Production Build

# Build production bundle
pnpm build

# Preview production build locally
pnpm preview

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Author

• KenZ - osu! profile · GitHub