by Alexander Thomas (aka Dr. Lex)
This is an AppleScript which is an extended version of the “Rescan QuickTime Metadata” scripts that can be found on the XiphQT Trac. Next to importing the metadata in Ogg files that XiphQT/iTunes misses (like year, track number, composer, …), it also gets the ReplayGain values if available, and converts them to iTunes ‘Volume adjustment’ values. In short, you can now both import missing metadata like track numbers and dates, and use ReplayGain on your Ogg files!
ReplayGain is an open source variant of the “Sound Check” feature built into iTunes. In other words, it calculates an optimal volume adjustment such that every song plays at the same perceived loudness. Because ReplayGain analyzes the entire file while Sound Check only seems to sample some parts of the song, ReplayGain generally gives better results.
To avoid problems, unzip the file with OS X' built-in unzip functionality (don't use StuffIt Expander). Read the included ReadMe file for installation instructions.
Because this requires AppleScript, it will only work in recent versions of iTunes in OS X. You also need to have vorbis-tools installed (e.g. through Fink). Of course, to play Oggs in iTunes you also need XiphQT.
Due to limitations of AppleScript, the script may not work properly if you try to run it on music files on an NFS share with non-ASCII characters in their file name. If possible, try to avoid using special characters in the names of such files (or mount your shares through afpd, which will avoid all kinds of NFS-related problems in general).
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
If you have looked at the actual ReplayGain values of your tracks, you may have noted that more recent tracks often have a more negative dB adjustment. If you want to know why this is the case, another article on this site explains it in detail.