Osu Rate Changer Library

A Rust library for modifying osu! beatmap and audio speeds with high precision. If you want to try what it look like you can check on Cobra

Library Features

• Rate modification for .osu files and associated audio
• Audio speed adjustment with quality preservation
• Comprehensive error handling with eyre
• Safe file path handling
• Cross-platform compatibility

Projet Structure

├── Cargo.lock
├── Cargo.toml
├── readme.md
└── src
    ├── audio.rs // modify audio
    ├── constants.rs // constants that can be changed.
    ├── lib.rs 
    └── osu.rs // modify osu and create a new one

Installation

Add this to your Cargo.toml:

[dependencies]
osu_rate_changer = "0.1.0"

API Usage

use osu_rate_changer::{change_osu_speed, change_audio_speed};
use eyre::Result;

// Modify both beatmap and audio (Recommended)
fn rate_map(osu_file_path: &str, rate: f32) -> Result<()> {
}

// Modify only audio
fn change_audio_speed(input_path: &str, output_path: &str, rate: f32) -> Result<()> {
}

// Modify only .osu file
pub fn change_osu_speed(map: &mut Beatmap, input_path: &str, rate: f32, audio_path: &str) -> eyre::Result<()> {
}

Technical Specifications

Audio Processing Parameters

const SINC_LEN: usize = 256;
const F_CUTOFF: f64 = 0.95;
const OVERSAMPLING_FACTOR: usize = 256;
const BUFFER_SIZE: usize = 1152;
const DEFAULT_SAMPLE_RATE: u32 = 44100;
const BITS_PER_SAMPLE: u16 = 16;

Roadmap & Known Issues

1. Audio Processing
   • Issues:
     • Limited audio compression with current OGG format
     • High memory usage with large files
   • Improvements:
     • Implement Opus-OGG support via audiopus
     • Add stream processing for memory efficiency
     • Make audio processing parameters configurable
2. Timing & Map Features
   • Issues:
     • Breakpoint alignment causing unexpected breaks during gameplay
     • Inaccurate BPM display in editor
   • Improvements:
     • Enhance timing point synchronization algorithm
     • Implement precise breakpoint calculations
     • Better rate scaling for extreme values
3. Different Values
   • add support of differentes values like od etc

Contributing

Contributions are welcome!
Create an issue or contact me on discord : Osef0760

License

GNU license : just mention me and you are good to use how you want