Pure Data
Open SourcePure Data (Pd) is a widely-used graphical programming environment developed by Miller Puckette. It provides a visual interface for creating interactive computer music, multimedia works, and various forms of digital art through signal processing and event modeling.
                  
                    
                  
                  Key Features
                
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                      Free and open source.
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                      Powerful real-time audio and visual processing capabilities.
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                      Highly extensible via external libraries.