Tried mp3gain on files I created from 3.99.3, and am still getting errors. I found that if I use EAC and rip to wav files, and then compress those wav files into mp3, I don't get the "is an MPEG Layer I file, not a layer III file" error in mp3gain. So there must be an issue in the tags that EAC is writing when I choose the "Test & copy selected tracks - compressed" option. Anyone else run into that? Is there something in my command line? -V 2 --add-id3v2 --pad-id3v2 --ta "%a" --tt "%t" --tg "%m" --tl "%g" --ty "%y" --tn "%n" %s %d Starting with EAC 1.0 beta 2 and on, placeholder names have changed. From the EAC website:Which flags can I use in the external compression scheme “User Defined MP3 Encoder”? In the field “Additional command line options” you could use replacements for the selectable options : For versions before 1.0 beta 2 %s – Source filename %d – Destination filename %h…%h – Text “…” only when “High quality” selected %l…%l -Text “…” only when “Low quality” selected %c…%c – Text “…” only when “CRC checksum” selected %j…%j – Text “…” only when storing cd cover is enabled %i – Filename of CD cover image %r – Bitrate (“32″..”320″) %e – Comment %a – Track artist %t – Track title %v – CD artist %g – CD title %y – Year %n – Track number %x – Number of tracks on album %m – MP3 music genre %o – Original filename (without temporary renaming) %e – Comment (as selected in EAC) %b – CRC of extracted track %f – freedb ID So a command line would look like (for l3enc) %s %d -br %r000 %h-hq%h %c-crc%c For versions from 1.0 beta 2 on (some placeholders might only be available in the latest version!) %source% – Source filename %dest% – Destination filename %original% – Original filename (without temporary renaming) %ishigh%…%ishigh% – Text “…” only when “High quality” selected %islow%…%islow% -Text “…” only when “Low quality” selected %haslyrics%…%haslyrics% – Text “…” only when lyrics exist %hascover%…%hascover% – Text “…” only when storing cd cover is enabled and cover exists %crcenabled%…%crcenabled% – Text “…” only when “CRC checksum” selected %title% – Track title %genre% – MP3 music genre %year% – Year %cddbid% – freedb ID %artist% – Track artist %lyrics% – Lyrics %lyricsfile% – Filename of lyrics text file (ANSI) %bitrate% – Bitrate (“32″..”320″) %comment% – Comment (as selected in EAC) %tracknr% – Track number (same as %tracknr2%) %tracknr1% – Track number (at least 1 digit) %tracknr2% – Track number (at least 2 digits) %tracknr3% – Track number (at least 3 digits) %totalcds% – Total number of CDs in the given CD set %cdnumber% – Number of the CD %composer% – Track performer %trackcrc% – CRC of extracted track %coverfile% – Filename of CD cover image %numtracks% – Number of tracks on album %albumtitle% – CD title %albumartist% – CD artist %albumcomposer% – CD composer %albuminterpret% – CD performer %% – The ‘%’ character So a command line would look like (for l3enc) %source% %dest% -br %bitrate%000 %ishigh%-hq%ishigh% %crcenabled%-crc%crcenabled% The extension can also be selected within these settings.