Soundpipe

Soundpipe is a lightweight music DSP library written in C. It aims to provide a set of high-quality DSP modules for composers, sound designers, and creative coders.

Soundpipe supports a wide range of synthesis and audio DSP techniques which include:

• Classic Filter Design (Moog, Butterworth, etc)
• High-precision and linearly interpolated wavetable oscillators
• Bandlimited oscillators (square, saw, triangle)
• FM synthesis
• Karplus-strong instruments
• Variable delay lines
• String resonators
• Spectral Resynthesis
• Partitioned Convolution
• Physical modeling
• Pitch tracking
• Distortion
• Reverberation
• Samplers / sample playback
• Padsynth algorithm
• Beat repeat
• Paulstretch algorithm
• FOF and FOG granular synthesis
• Time-domain pitch shifting

More information on specific Soundpipe modules can be found in the Soundpipe module reference guide.

Features

• High quality modules ported from Csound and FAUST
• Sample accurate timing
• Small codebase
• Static library
• Easy to extend
• Easy to embed

Compilation

By default, Soundpipe needs libsndfile, and a standard build environment. Other modules that use other external libraries will need to be explicitly compiled by modifying config.mk.

To compile:

make

sudo make install

Examples

To build the examples, go into the examples folder and run "make", which will create files with a .bin extention. To run an example, run "./ex_foo.bin". When an example is run, it will generate a 5 second file called "test.wav".

Tests

Tests in Soundpipe are used to determine whether or not modules behave as expected. Tests write the output of a module to memory, and check the MD5 hash value of the output against the MD5 value of a reference signal.

To build a test file, go into the test folder, and run "make". Then, run "./run.bin", which runs the tests. As the tests are run, an "ok" will appear in the log if a test passes, and a "not ok" will appear if a test fails.

It is possible to hear the output of a particular test if you know the test number. You will need to have sox installed. For example, to hear what test 11 sounds like, run the following commands:

./run.bin render 11

./write_wave.sh 0011.raw

This will generate a file called out.wav.

The testing utility has a few optional arguments. To see all possible arguments, run "./run.bin help".

The Soundpipe Model

Soundpipe is callback driven. Every time Soundpipe needs a frame, it will call upon a single function specified by the user. Soundpipe modules are designed to process a signal one sample at a time. Every module follows the same life cycle:

1. Create: Memory is allocated for the data struct.
2. Initialize: Buffers are allocated, and initial variables and constants are set.
3. Compute: the module takes in inputs (if applicable), and generates a single sample of output.
4. Destroy: All memory allocated is freed.

Documentation

If you have lua installed on your computer, you can generate the current html documentation for soundpipe by running "make docs". A folder called "docs" will be created. The top page for the documentation is docs/index.html.

Licensing

Code adapted from Csound opcodes fall under the LGPL license (these are mentioned in their source headers). Everything else falls under the MIT license.