Pd (aka Pure Data) is a real-time graphical programming environment
for audio, video, and graphical processing. It is the third major
branch of the family of patcher programming languages known as Max
(Max/FTS, ISPW Max, Max/MSP, jMax, etc.) originally developed by
Miller Puckette and company at IRCAM. The core of Pd is written
and maintained by Miller Puckette and includes the work of many
developers, making the whole package very much a community effort.

Pd was created to explore ideas of how to further refine the Max
paradigm with the core ideas of allowing data to be treated in a
more open-ended way and opening it up to applications outside of
audio and MIDI, such as graphics and video.

It is easy to extend Pd by writing object classes ("externals") or
patches ("abstractions"). The work of many developers is already
available as part of the standard Pd packages and the Pd developer
community is growing rapidly. Recent developments include a system
of abstractions for building performance environments; a library
of objects for physical modeling; and a library of objects for
generating and processing video in realtime.

Homepage:
https://puredata.info/
