aacgain − normalizes the volume of digital music files


aacgain [options] <infile> [<infile 2> ...]


aacgain version 1.9.0, derived from mp3gain version 1.5.2 copyright(c) 2001−2009 by Glen Sawyer AAC support copyright(c) 2004−2009 David Lasker, Altos Design, Inc. uses mpglib, which can be found at AAC support uses faad2 (, and mpeg4ip’s mp4v2 (


−v − show version number

−g <i> − apply gain i without doing any analysis

−l 0 <i> − apply gain i to channel 0 (left channel)

without doing any analysis (ONLY works for STEREO files, not Joint Stereo)

−l 1 <i> − apply gain i to channel 1 (right channel)

−e − skip Album analysis, even if multiple files listed

−r − apply Track gain automatically (all files set to equal loudness)

−k − automatically lower Track/Album gain to not clip audio

−a − apply Album gain automatically (files are all from the same

album: a single gain change is applied to all files, so their loudness relative to each other remains unchanged, but the average album loudness is normalized)

−m <i> − modify suggested MP3 gain by integer i

−d <n> − modify suggested dB gain by floating−point n

−c − ignore clipping warning when applying gain

−o − output is a database−friendly tab−delimited list

−t − writes modified data to temp file, then deletes original

instead of modifying bytes in original file A temp file is always used for AAC files.

−q − Quiet mode: no status messages

−p − Preserve original file timestamp

−x − Only find max. amplitude of file

−f − Assume input file is an MPEG 2 Layer III file

(i.e. don’t check for mis−named Layer I or Layer II files)

This option is ignored for AAC files.

−? or −h − show this message

−s c − only check stored tag info (no other processing)

−s d − delete stored tag info (no other processing)

−s s − skip (ignore) stored tag info (do not read or write tags)

−s r − force re−calculation (do not read tag info)

−s i − use ID3v2 tag for MP3 gain info

−s a − use APE tag for MP3 gain info (default)

−u − undo changes made (based on stored tag info)

−w − "wrap" gain change if gain+change > 255 or gain+change < 0

MP3 only. (use "−? wrap" switch for a complete explanation)

If you specify −r and −a, only the second one will work If you do not specify −c, the program will stop and ask before

applying gain change to a file that might clip