Beets is a media library management system designed for obsessive-compulsive music geeks. It catalogs your collection, automatically improving its metadata as it goes using the MusicBrainz database. It also downloads cover art for albums it imports. Then it provides a bouquet of tools for manipulating and accessing your music. Beets also includes a music player that speaks the MPD protocol, so you can play music in your beets library using any MPD client.
id3j is a lightweight and easy-to-use library to create and add ID3 metadata tags to MP3 files. It only concerns itself with ID3 version 3.2.0 and only handles the most common types of information, but creating a tag and adding it to a file is much easier than with many other solutions. It also has one fairly esoteric feature that is interesting from a algorithmical standpoint, which is the ability to create CRC32 neutral ID3 tags. That means that you can add such a tag to any MP3 file and the CRC32 sum of the resulting MP3 file with the tag will be the same as the file without the tag.
The Ultimate Live Music Audio Converter is an audio conversion tool specifically designed around the file formats used for live music trading. It currently supports conversion of SHN, FLAC, and WAV files to MP3 or Ogg. Advanced features include automatic tagging of files using the contents of a set-list file (MP3, Ogg, and FLAC only), upload of new files into Itunes Library, and scanning directories where new files are downloaded (manual or automatic).
Guayadeque is a music player that aims to be easy to use and fast even for huge music collections. It allows you to automatically or manually download covers, easily organize the music library, edit the ratings of the tracks, add labels to the artists, albums, and tracks, listen to shoutcast radios, download lyrics, show artist information based on last.fm content, and more. It includes a simple, built-in tag editor with picture support.
MIDI to MP3 Converter for Mac is a tool that converts MIDI files to MP3 or WAV. It uses an intelligent conversion technique, allowing you to convert a 5 minute MIDI file in just a few seconds. It also produces high quality sound that may significantly surpass capabilities of your built-in sound card. MIDI to MP3 Converter uses SoundFonts to perform the converion, which greatly increases flexibility. You can choose an appropriate SoundFont for every MIDI file, or even supply each instrument of your composition with an individual SoundFont (piano, guitar, trumpet etc.). MIDI to MP3 Converter includes an editor for controlling ID3 tag information in the output files. The program also offers a number of sound effects. It is possible to set tempo, reverb, and chorus effects.
Midi Converter for Mac is a small and simple utility designed mostly for musicians who compose music using their computer. However, it can be very useful for anyone who wants to convert MIDI music files to MP3 or other popular formats. It is around 10 times faster than the other competing programs, because it converts the files directly rather than having to record them first. The program is very easy to use, and a trial version is available. It also allows you to embed a player, and has a number of other features. It does not rely on your sound card with regards to the quality of the final output, so you can expect high and consistent quality, regardless of what sort of computer you are going to use it on.