Zita convolver is a C++ library providing a real-time convolution engine.

JACK is a low-latency audio server. It can connect a number of different applications to an audio device, as well as allowing them to share audio between themselves. JACK is different from other audio server efforts in that it has been designed from the ground up to be suitable for professional audio work. This means that it focuses on two key areas: synchronous execution of all clients, and low latency operation.

lv2toweb allows the user to create an xhtml page with information about the given LV2 plugin, provided that the plugin and its UI(s) match up with the provided metadata and adhere to well-known best practices.

DarkIce is a live audio streamer. It takes audio input from a sound card, encodes it into Ogg Vorbis and/or mp3, and sends the audio stream to one or more IceCast and/or ShoutCast servers.

LibTiMidity is a MIDI to WAVE converter library that uses Gravis Ultrasound-compatible patch files to generate digital audio data from General MIDI files.

Game-music-emu is a collection of video game music file emulators that support the following formats and systems:

AY

ZX Spectrum/Asmtrad CPC

GBS

Nintendo Game Boy

GYM

Sega Genesis/Mega Drive

HES

NEC TurboGrafx-16/PC Engine

KSS

MSX Home Computer/other Z80 systems (doesn't support FM sound)

NSF/NSFE

Nintendo NES/Famicom (with VRC 6, Namco 106, and FME-7 sound)

SAP

Atari systems using POKEY sound chip

SPC

Super Nintendo/Super Famicom

VGM/VGZ

Sega Master System/Mark III, Sega Genesis/Mega Drive, BBC Micro

FreePats is a project to create a free and open set of GUS compatible patches that can be used with softsynths such as Timidity and WildMidi.

FluidSynth is a real-time software synthesizer based on the SoundFont 2 specifications. FluidSynth reads and handles MIDI events from the MIDI input device. It is the software analogue of a MIDI synthesizer. FluidSynth can also play midifiles using a Soundfont.

LibOFA is an audio fingerprint library, created and provided by MusicIP.

This C++ library implements the Butterworth, RBJ, and Chebychev IIR filters. Samples are processed one by one, in real time. It can easily import coefficients generated with Python (scipy). It also avoids memory leaks by allocating memory at compile time, using templates, instead of calling malloc() or new.

This package contains wrappers for accessing the ALSA API from Python. It is currently fairly complete for PCM devices, and has some support for mixers.

The jack_mixer is a GTK+ JACK audio mixer app with a look & handling similar to hardware mixing desks. It has lot of useful features, apart from being able to mix multiple JACK audio streams.

CLAP stands for CLever Audio Plugin. It is an audio plugin ABI which defines a standard for Digital Audio Workstations and audio plugins to work together.

SBSMS (Subband Sinusoidal Modeling Synthesis) is software for time stretching and pitch scaling of audio. This package contains the library.

OpenSLES is a royalty-free, cross-platform, hardware-accelerated audio API tuned for embedded systems. It provides a standardized, high-performance, low-latency method to access audio functionality for developers of native applications on embedded mobile multimedia devices, enabling straightforward cross-platform deployment of hardware and software audio capabilities, reducing implementation effort, and promoting the market for advanced audio.

Libmixed is a library for real-time audio processing pipelines for use in audio/video/games. It can serve as a base architecture for complex DSP systems.

Ecasound is a software package designed for multitrack audio processing. It can be used for simple tasks like audio playback, recording and format conversions, as well as for multitrack effect processing, mixing, recording and signal recycling. Ecasound supports a wide range of audio inputs, outputs and effect algorithms. Effects and audio objects can be combined in various ways, and their parameters can be controlled by operator objects like oscillators and MIDI-CCs. A versatile console mode user-interface is included in the package.

Cubeb is Mozilla's cross-platform audio library.

ZToolkit (Ztk) is a cross-platform GUI toolkit heavily inspired by GTK. It handles events and low level drawing on behalf of the user and provides a high-level API for managing the UI and custom widgets. ZToolkit is written in C and was created to be used for building audio plugin UIs, where the dependencies often need to be kept to a minimum.

Codec 2 is a speech codec designed for communications quality speech between 700 and 3200 bit/s. The main application is low bandwidth HF/VHF digital radio.

Snd is a sound editor modelled loosely after Emacs. It can be customized and extended using either the s7 Scheme implementation (included in the Snd sources), Ruby, or Forth.

Dcadec is a DTS Coherent Acoustics surround sound decoder with support for HD extensions.

Qsynth is a GUI front-end application for the FluidSynth SoundFont synthesizer written in C++.

audio-to-midi converts audio files to multichannel MIDI files. It accomplishes this by performing FFTs on all channels of the audio data at user-specified time steps. It then separates the resulting frequency analysis into equivalence classes which correspond to the twelve tone scale; the volume of each class being the average volume of its constituent frequencies. This data is then formatted to MIDI and written to disk.