sph-sp
c code and shared library for sound synthesis and sequencing. the sound processor implementations can serve as examples.
features
- basics
- processing of non-interleaved sample arrays with one array per channel
- unlimited number of channels and unlimited sample rate
- 64 bit float sample format by default, other formats possible for many processors
- 32 bit float wav file output and input
- plotting of samples and sound spectra using gnuplot
- fast fourier transform (fft) and inverse fast fourier transform (ifft)
- processors that work seamlessly on blocks of continuous data streams
- windowed-sinc low-pass, high-pass, band-pass and band-reject filters
- state-variable low/high/band/all-pass filter
- convolution
- moving average filter
- synthesis
- linear and bezier interpolation between points for envelopes and other control data
- lookup-table oscillator for sinusoids and other wave shapes with a stable phase and time-dependent frequency and amplitude changes provided by arrays
- white noise generator
- sequencing
- event renderer for parallel block processing with custom routines
- events for sines and filtered noise
- event groups that compose for instruments, riffs and songs
- per channel configuration with optional channel delay
- array processing
- arithmetic, permutations, statistics, and more
code example
see other/example.c or alternatively other/example.sc
documentation
dependencies
- linux or compatible (libc)
- gcc and shell for the provided compile script
- optional: gnuplot
- optional: sph-sc, for development on sph-sp itself or for using the sc macros
setup
- install dependencies as needed
- execute the following from the project directory
./exe/compile-c
./exe/install
the first argument to exe/install can be the destination path prefix, for example ./exe/install /tmp.
installed files
- /usr/include/sph-sp.h
- /usr/include/sph-sp/*
- /usr/lib/libsph-sp.so
- /usr/share/sph-sp/sc-macros.sc
compile-time configuration options
the ifndefs at the top of source/c-precompiled/sph-sp/sph-sp.h can be customised before compilation. custom preprocessor variables can be set before including the header when embedding the full code, or a customized header must be used when using a shared library that has been compiled with the same configuration.
some options that can be configured:
| name | default | description |
|---|---|---|
| sp_channel_count_t | uint8_t | data type for numbers of channels |
| sp_channel_limit | 2 | maximum number of channels |
| sp_sample_t | double | float data type for samples (quasi continuous) |
| sp_time_t | uint32_t | integer data type for sample counts (discrete) |
c usage
#include <sph-sp.h>
call sp_initialize(cpu_count, default_channel_count, default_sample_rate) once before using other features. for example sp_initialize(1, 2, 48000).
compilation of programs using sph-sp with gcc
gcc -lsph-sp main.c
license
- files under
source/c/foreign/nayuki-fft: mit license - rest: lgpl3+
thanks to
- tom roelandts on whose information the windowed sinc filters are based on
- mborg for the first fft implementation that was used
- mhroth for a simple example of reading/writing wav files
- nayuki for the concise fft implementation that is currently used
- steve smith's dspguide for information about dsp theory
- xoshiro.di.unimi.it for the pseudorandom number generator