sndc

sndc is a modular, non real time synthesizer that essentially behaves like a compiler for sound effects.

It turns source files (.sndc files), which are essentially directed acyclic graphs of data transferred from generators through various effect modules into a float buffer which can then be converted to sound files or played with external tools.

This is supposed to be a programmer/nerd friendly way of quickly hacking together complex sound effects and potentially even music, with source files that can be easily added to a VCS like git, and generation that's build-system friendly when integrated into a complex project such as a video game.

Build

Dependencies:

• libfftw3

$ git clone https://pedantic.software/git/sndc
$ cd sndc
$ make

You can install sndc and its wrappers with make install.

Write a sound effect source

A source file is a collection of nodes. Each node is an instance of a particular module. A node is declared like so:

nodeName: moduleName {
    /* list of inputs */
}

Each module has a set of inputs, whose type can be either FLOAT, BUFFER or STRING. Of course this is an ongoing project and further data types will be added in the future. They are set like so:

    inputName: inputValue;

Some inputs are required and some are optional depending on the module. inputValue can be either a literal value, or the output of a node above the current node. Example:

newNode: myModule { /* node named "newNode", instance of "myModule" */
    input: n.out;   /* "input" is set to an output buffer of a previous node */
    freq: 440;      /* "freq" is set to a literal float */
    interp: "sine"; /* "interp" is set to a literal string */
}

For a better overview, look at the examples in the examples directory.

You can list all built-in modules with:

$ ./sndc -l

You can list inputs of a particular module, along with their type and whether they are required, with:

$ ./sndc -h moduleName

Play/export sound

sndc follows the UNIX philosophy and as such, delegates the task of playing and converting the output binary data to external tools.

Linux users will find that tools such as aplay for playing and sox for converting raw output are a good fit.

sndc will go through the input file, load all modules in memory, perform basic sanity checks of input types, then print the raw content of the output of the last module in the stack, either in the specified output file or in stdout.

A typical invocation of sndc piped into aplay for immediate replay of the sound might look like this:

$ ./sndc file.sndc | aplay -c 1 -t raw -r 44100 -f float_le

Note that the float_le is specific for little endian machines, big endian machines should use float_be instead.

Similarly, to convert the output into whatever audio format the user desires, one should use sox with an invocation such as:

$ ./sndc file.sndc | sox -t raw -r 44100 -c 1 -L -e floating-point -b 32 - out.wav

Some convenient wrappers are located in the wrappers directory, they get installed along with sndc when typing make install.

To play a sndc file using the wrapper over aplay:

$ sndc_play <sndcfile>

To export using the wrapper over sox:

$ sndc_export <sndcfile> <audiofile>

Notes

This is an ongoing project with heaps of improvements yet to do, but the basic idea is more or less already there.