beaTunes is an iTunes companion app capable of automatically analyzing your music collection to help you build better playlists. It analyzes BPM (beats per minute), silence at the beginning or end of a song, and the color (based on frequency spectrum) of a given song. Some of the data is stored through iTunes, and some is stored by beaTunes itself. beaTunes can suggest albums that would complement your music collection, display music charts, and help you find and fix errors in your song meta data, like typos and wrong genres. It also allows you to blog about selected songs or playlists.
DansTuner is a program to tell you if you are playing a pitch in tune. Major features include automatic discovery of which note you are trying to play (good for trumpet, singer, etc.), the ability to play a guide tone at a configurable volume, a graphical moving "needle" with a red/green display and detail about how flat or sharp you are, and an easily configurable background noise threshold.
Twibright Pitchotron analyzes any MP3 into the semitones that are being played, displayed in a scrolling coloured graph on a video. It aids musical transcription. It includes coloured piano key stickers that enable accompanying arbitrary music and improvising even to musical analphabets.
Transcribe! is an assistant for working out a piece of music from a recording. It offers many features aimed at making the transcription job smoother and easier, including the ability to slow down the music without changing its pitch, and to analyse chords and show you what notes are present.
getID3() is a PHP script that extracts useful information from MP3s and other multimedia file formats. It extracts information like the play time, bitrate, and resolution from the following file formats: MP3, Ogg Vorbis, WAV, AVI, Matroska (MKV), MPEG-1 video, Windows Media (ASF, WMA, WMV), RealAudio & RealVideo, Monkey's Audio, FLAC & OggFLAC, VQF, Speex, Musepack (MPC), AAC, AU, VOC, AIFF, OptimFROG, WavPack, LiteWave, LPAC, RKAU, SZIP, Shorten, Quicktime, NSV, MIDI, ZIP, ISO9660, TTA, PhotoCD, BMP, PNG, GIF, and JPEG. It parses information from ID3v1, ID3v2, Ogg Vorbis, Lyrics3 v1 & v2, RIFF (AVI, WAV, CDA, CART, BWF), APE, ReplayGain, PNG, and GIF tags, and can write ID3v1, ID3v2, APE2, FLAC, and Ogg Vorbis tags.