rsgain

rsgain (really simple gain) is a ReplayGain 2.0 command line utility. It applies loudness metadata tags to audio files without altering the audio stream itself. When used with a ReplayGain-compatible player, the player will dynamically adjust the volume based on these tags.

Key characteristics:

• Batteries included: Designed to scan entire music libraries without external scripts.
• Multiple interfaces: Available as a CLI or as a backend for the MusicBrainz Picard ReplayGain 2.0 plugin (which provides a GUI).

When scanning, you can choose how the peak value (used to predict clipping) is calculated.

• Sample Peak (Default): The highest value sample in the signal. It is faster to calculate.
• True Peak: Uses interpolation to approximate the original analog signal, accounting for intersample peaks. This is more accurate but significantly slower (typically 2-4x longer scans) due to the computational intensity of the oversampling process.

To avoid re-scanning files that already contain ReplayGain information, use the -S or --skip-existing flag.

Behavioral details:

• It checks for the existence of the REPLAYGAIN_TRACK_GAIN tag.
• If album tags are enabled, the check is collective: if even one file in an album is missing the tags, the entire album is scanned.
• It does not verify if existing tags are complete or compatible with your current target loudness settings.

rsgain easy -S /path/to/music/library

rsgain uses UTF-8 for Unicode. To ensure full compatibility with all filenames (including those with non-ANSI characters), it is strongly recommended to run rsgain on Windows 10 version 1903 or later, which provides full UTF-8 support.

If you are using Windows Vista through 8.1, rsgain will still function, but it will only work correctly if your filenames do not contain Unicode/non-ANSI characters.

Building on Windows requires Visual Studio (with C++ core desktop features and C++ CMake tools), Git, and CMake. It uses vcpkg to manage dependencies.

1. Clone and Prepare: Clone the repository and create a build directory.
2. Configure: Run cmake with the -DVCPKG=ON flag to build dependencies via vcpkg and generate Visual Studio project files.
3. Build: Use cmake --build to compile the project.
4. Run: Execute the resulting .exe from the Release folder.

Optional: To generate a zipped install package, use the --target package flag during the build step.

git clone https://github.com/complexlogic/rsgain.git
cd rsgain
mkdir build
cd build
cmake .. -DVCPKG=ON
cmake --build . --config Release
.\Release\rsgain.exe

The build system supports creating Debian packages using CPack.

1. Configure CMake with -DPACKAGE=DEB and set the install prefix (e.g., -DCMAKE_INSTALL_PREFIX=/usr).
2. To target a specific architecture, use -DCPACK_DEBIAN_PACKAGE_ARCHITECTURE=architecture.
3. Run make package to build the package.

Example for amd64:

cmake .. -DPACKAGE=DEB -DCMAKE_INSTALL_PREFIX=/usr
make package

Portable Binaries

Download the correct ZIP for your hardware from the Release Page:

• Apple Silicon: rsgain-3.7-macOS-arm64.zip
• Intel: rsgain-3.7-macOS-x86_64.zip

Note on Gatekeeper: Since these builds are not codesigned, macOS may block execution. To allow it, remove the quarantine bit using xattr:

xattr -d com.apple.quarantine /path/to/rsgain

Package Managers

Install via Homebrew or MacPorts:

• Homebrew: brew install rsgain
• MacPorts: port install rsgain

You can use rsgain as a backend for the ReplayGain 2.0 plugin in MusicBrainz Picard to provide a GUI for ReplayGain calculations.

Setup Steps:

1. Install Plugin: In Picard, go to Options -> Plugins, find ReplayGain 2.0, and click download.
2. Install rsgain: Ensure rsgain is installed on your system separately.
3. Configure Path: In the plugin settings, set the path to the rsgain executable.
   • On Unix, rsgain is usually in your PATH.
   • On Windows, provide the full path to rsgain.exe or add its folder to your system Path.
4. Calculate Gain:
   • Add files to Picard and associate them with a release.
   • Right-click an album or track and select Plugins -> Calculate ReplayGain.
   • Important: This calculates the values but does not tag them. You must click the Save button in Picard to write the tags to the files.

Custom Mode is a legacy-style interface similar to mp3gain. Unlike Easy Mode, it operates on specific files rather than directories and is intended for users requiring high control or for use in scripts.

Usage: Invoke with rsgain custom followed by options and a list of files.

Example: Scan and tag specific MP3 files with album tags enabled (-a) and specific tag mode (-s i):

rsgain custom -a -s i file1.mp3 file2.mp3 file3.mp3

Run rsgain custom -h for the full list of available options.