ReplayGain 2.0 loudness normalizer based on the EBU R128 standard

 loudgain is a loudness normalizer that scans music files and calculates
 loudness-normalized gain and loudness peak values according to the
 EBU R128/ITU BS.1770 standard (-18 LUFS).
 .
 loudgain will embed ReplayGain 2.0-compatible metadata tags in a file if
 requested but will not modify the audio data in any way.
 .
 loudgain supports the FLAC, Ogg, MP2, MP3, MP4, M4A, ALAC, Opus, ASF, WMA, WAV,
 WavPack, AIFF and APE audio formats. Video files with compatible audio streams
 are also supported.