This is an open-source re-implementation of the NullSoft Expression Evaluation Library 2, as used in the Milkdrop music visualizer.

r128gain is a multi platform command line tool to scan your audio files and tag them with loudness metadata (ReplayGain v2 or Opus R128 gain format), to allow playback of several tracks or albums at a similar loudness level. r128gain can also be used as a Python module from other Python projects to scan and/or tag audio files.

cyanrip is a command line tool for ripping CDs. It uses MusicBrainz to name and tag each track, and to download and embed cover art. cyanrip supports encoding tracks to multiple formats in parallel and automatically verifies checksums.

QM-DSP is a C++ library of functions for DSP and Music Informatics purposes developed at Queen Mary, University of London.

RtOSC is a realtime safe library for handling OSC messages.

This package provides a LADSPA plugin for a stereo reverb effect.

Csound is a user-programmable and user-extensible sound processing language and software synthesizer.

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.

The SoX Resampler library (libsoxr) performs one-dimensional sample-rate conversion. It may be used, for example, to resample PCM-encoded audio.

This is a TUI volume control application for pipewire built with ncurses. Heavily inspired by pulsemixer and pwvucontrol.

This package provides rsgain, a ReplayGain 2.0 command line utility. rsgain applies loudness metadata tags to files, while leaving the audio stream untouched. A ReplayGain-compatible player will dynamically adjust the volume of tagged files during playback.

Cubeb is Mozilla's cross-platform audio 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.

lv2lint is an LV2 lint-like tool that checks whether a given plugin and its UI(s) match up with the provided metadata and adhere to well-known best practices.

Ableton Link is a C++ library that synchronizes musical beat, tempo, and phase across multiple applications running on one or more devices. Applications on devices connected to a local network discover each other automatically and form a musical session in which each participant can perform independently: anyone can start or stop while still staying in time.

WildMIDI is a simple software midi player which has a core softsynth library that can be used with other applications.

Vamp is an audio processing plugin system for plugins that extract descriptive information from audio data — typically referred to as audio analysis plugins or audio feature extraction plugins.

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.

Dexed is a multi-platform, multi-format plugin synthesizer. The sound engine is closely modeled on the original Yamaha DX7 characteristics. Dexed is also a MIDI cartridge librarian/manager for the DX7. Features include:

1. 144 DAW automatable DX7 parameters available from one single panel;

2. It fully supports DX7 input and output Sysex messages; including controller change. This means that you can use this with a native DX7/TX7 as a patch editor and sysex manager.

3. Every FM operator has a realtime VU meter to know which one is active.

4. It can load/save any DX7/TX7 sysex programs. It is also possible to save a single program into a different sysex file.

Dexed can be configured to use some of the original math limitation of a DX synthesizer. This does not only apply to the DAC, it also involves the bit resolution of the sine waves and the way that the amplitude is applied to each operator. Dexed comes with three engine types:

1. Modern: this is the original 24-bit implementation.

2. Mark I: Based on the OPL Series but at a higher resolution (LUT are 10-bits). The target of this engine is to be closest to the real DX7.

3. OPL Series: this is an experimental 8-bit implementation of the reversed engineered OPL family chips.

Calf Studio Gear is an audio plug-in pack for LV2 and JACK environments. The suite contains lots of effects (delay, modulation, signal processing, filters, equalizers, dynamics, distortion and mastering effects), instruments (SF2 player, organ simulator and a monophonic synthesizer) and tools (analyzer, mono/stereo tools, crossovers).

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.

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 provides pythonic libsndfile wrapper to read and write audio files.

This package provides a Python high-level interface and ctypes-based bindings for PulseAudio (libpulse), to use in simple synchronous code. This wrapper is mostly for mixer-like controls and introspection-related operations, as opposed to e.g. submitting sound samples to play and player-like clients.