Audacity is a cross-platform multitrack audio editor. It allows you to record sounds directly or to import Ogg, WAV, AIFF, AU, IRCAM, or MP3 files. It features a few simple effects, all of the editing features you should need, and unlimited undo. The audio I/O uses PortAudio, which fully supports OSS, Mac OS X CoreAudio, and Windows WMME, and can be compiled with support for ALSA and Jack.
The Snack sound extension adds commands for sound play/record and sound visualization, e.g. waveforms and spectrograms. It supports in- memory sound objects, file based audio, streaming audio, WAV, AU, AIFF, and MP3 file formats, synchronous and asynchronous playback. The visualization canvas item types update in real-time and can output postscript. New commands and file formats can be added using the Snack C-API.
jMax is a visual programming environment for building interactive real-time musical and multimedia applications by allowing the user to interactively design dataflow circuits. The basic data types that can go through are integers, symbols, lists, etc. It is an event-driven system and has been used for MIDI processing. A second part of the system (DSP) allows a continuous signal to flow through a circuit, which is most useful for PCM sound (ie. microphone, sound files, etc.). The system is extensible by using shared libraries, you may add data processor types, data types, GUI elements, device types, and more. Data processors may also be designed as circuits and reused.
Freecycle is a beat slicer providing amplitude domain and frequency domain beat matching and zero crossing algorithms. It exports sliced audio chunks and generates a MIDI file which can be used to play the sliced loop. Alternatively, you can jam with it as soon as you've made slices using a MIDI keyboard or sequencer. Freecycle also exports AKAI S5000/S6000/Z4/Z8 .AKP files to be used with your favorite sampler, SoundFont files, and supports slice drag and drop from the application to the desktop. It can process the audio inline using LADSPA effects, as well as applying envelopes to seperate slices.
aubio is a library for audio labelling. Features include onset detection, silence detection, beat tracking, and pitch detection. The goal of this project is to provide automatic labelling features to other audio software projects. Functions can be used offline in sound editors and software samplers, or online in audio effects and virtual instruments.
Sonic Visualiser is an application for viewing and analysing the contents of music audio files, containing advanced waveform and spectrogram viewers as well as editors for many sorts of audio annotations. It supports sophisticated audio selection, looping, and playback features, as well as the Vamp audio feature extraction plugin format.
AudioSlicer is a Cocoa GUI application that finds all silences in an audio file and allows you to split it into several smaller audio files and to name/tag them properly. While most other tools split automatically according to certain criteria, AudioSlicer shows you all silences within a certain range of duration. You can then listen and decide whether you want to split there. The splitting is done without loss; there is no decoding and re-encoding of audio data.