mp3rgain is a modern tool designed for lossless MP3 volume adjustment by modifying the global_gain field in each frame's side information. This approach preserves audio quality while enabling permanent volume changes without re-encoding.
Key Features:
Lossless & Reversible Adjustments: Volume changes are applied directly to the file, allowing for reversible adjustments without any loss of audio quality.
ReplayGain Analysis: Supports track and album gain analysis, ensuring consistent listening levels across tracks or albums.
AAC/M4A Support: Compatible with AAC and M4A files, expanding its utility beyond MP3s.
Cross-Platform Compatibility: Works seamlessly on macOS, Linux, and Windows (including x86_64 and ARM64 architectures).
Command-Line Compatibility: Fully compatible with the original mp3gain command-line interface, providing a familiar workflow for users.
Audience & Benefit:
Ideal for audiophiles, music producers, and anyone requiring precise volume control over their audio files. By eliminating the need for re-encoding, mp3rgain ensures that adjustments are lossless, maintaining the highest possible audio quality while achieving consistent listening levels across tracks or albums.
The software can be installed via winget on Windows for a streamlined experience.
README
mp3rgain
Lossless MP3/AAC volume adjustment - a modern mp3gain replacement written in Rust
mp3rgain adjusts MP3 and AAC volume without re-encoding by modifying the global_gain field in each frame. This preserves audio quality while achieving permanent volume changes.
Features
Lossless & Reversible: No re-encoding, all changes can be undone (MP3 and AAC)
ReplayGain: Track and album gain analysis for MP3 and AAC/M4A
Zero dependencies: Single static binary (no ffmpeg, no mp3gain)
Cross-platform: macOS, Linux, Windows (x86_64 and ARM64)
mp3gain compatible: Drop-in replacement with identical CLI
GUI Application: Native desktop app for drag-and-drop workflow
# Normalize a single track (ReplayGain)
mp3rgain -r song.mp3
# Normalize an album
mp3rgain -a *.mp3
# Manual gain adjustment (+3.0 dB)
mp3rgain -g 2 song.mp3
# Undo changes
mp3rgain -u song.mp3
# Show file info
mp3rgain song.mp3
Use Cases - Integration examples (beets, headroom, etc.)
Why mp3rgain?
The original mp3gain has been unmaintained upstream since ~2015 (though distribution maintainers continue to apply security patches). mp3rgain is a modern, memory-safe replacement written in Rust.
mp3rgain implements the ReplayGain 1.0 algorithm (89 dB reference level) for full compatibility with the original mp3gain. Loudness values will differ from EBU R128/LUFS-based tools (foobar2000, loudgain, ffmpeg loudnorm).
Library Usage
use mp3rgain::{apply_gain, analyze};
use std::path::Path;
let frames = apply_gain(Path::new("song.mp3"), 2)?; // +3.0 dB
let info = analyze(Path::new("song.mp3"))?;
