playerdo is a script for controlling a variety of different media players from a single command line interface. It is intended to be used with keyboard shortcuts, especially the media keys (play/pause, next, etc.) found on many keyboards. It automatically detects which media player is running and tries to do the right thing.
fretscpp is strongly inspired by the original FoF, reusing artwork to a large extent, with the source code rewritten from scratch. C++ instead of python should improve performance and allow easier support for features like whammy. It is playable, but some non-critical features are still missing.
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.
n-Track Studio is an audio and MIDI multitrack recorder that turns your computer into a full-fledged recording studio. You can record and playback a virtually unlimited number of audio and MIDI tracks. The program supports simultaneous recording from multiple 16-bit and 24-bit soundcards, and real-time audio effects can be applied non-destructively to each track. Built-in effects include Reverb, Multiband Compression, Chorus, Delay, Pitch Shift, Graphic and Parametric EQ, and spectrum analyzer. The program can use third party VST plug-ins to process audio signals in real-time. Effects can also be used to process the recorded signal in real-time. MIDI tracks can be imported end exported to regular MIDI files, and edited using the built in piano-roll based MIDI editing window. The program supports VSTi instrument plug-ins for sample accurate software MIDI playback. Volume and pan evolution can be programmed by drawing on the timeline window.
SpectMorph allows you to analyze samples of musical instruments and to combine them (morphing). It can be used to construct hybrid sounds, e.g. a sound between a trumpet and a flute, or smooth transitions, e.g. a sound that starts as a trumpet and then gradually changes to a flute. Interpolating between two samples of the same instrument (different attack velocity of a piano) could be interesting. The analysis process decomposes samples into a sum of sine waves (corresponding to the partials present in the signal, or the part of the signal perceived as "tone") and additional noise. SpectMorph is thus based on the research on Spectral Modelling Synthesis.
gst123 is a GStreamer-based command line audio player in the style of mpg123 and ogg123. The advantage over these tools is that gst123 can play every file GStreamer can, so mixed music collections with FLAC, Ogg, and MP3 files are no problem. Newer versions of gst123 additionally provide support for playing video files, while the ability to use gst123 without X11 display has been preserved.