Credits & licences

Built on open standards and open source.

LevelAudio measures loudness to published broadcast standards with its own code, and borrows FFmpeg for the formats it doesn't handle itself. LevelAudio’s own code is MIT-licensed.

Standards

  • Loudness and true peak: ITU-R BS.1770-4, as used by EBU R128.
  • Meter tests: reference tones from EBU Tech 3341.
  • Lossless MP3 gain: the global-gain technique made popular by mp3gain, in LevelAudio’s own implementation.

Libraries

  • FLAC and other re-encodes: FFmpeg via ffmpeg.wasm: the core is GPL-2.0-or-later, the loader MIT. An unmodified build, served from levelaudio.org and loaded only when a file needs it; its source is at those links.
  • ZIP downloads: fflate (MIT).