id3 metadata cloner
When considering to make a new purchase of mp3 files to get them in better quality, losing the id3 metadata in the process may be an hindrance to the upgrade.
Replica can help you having it both ways by cloning id3 metadata from the original file to the enhanced copy.
If you replicate full albums, please make sure that tracks filenames are similarly ordered in both source and destination folders.:
$ replica -u Library/Sam_Cooke-Ain_t_that_good_news-128kbps-2003 Incoming/sam_cook-good-news-320kbps Cloning id3 metadata... Done Renaming files......... Done
In addition to id3 cloning, replica can handle files renaming too so that upgrading mp3 files becomes a no-brainer.
Consider the -u option to remove the source files and replace them by their upgraded version. By doing so, it instantly migrates id3 metatags to new files while keeping the information stored by your music player (ratings, play counts, etc) valid as the tracks filepaths get unmodified.