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Developing with aubio
Here is a brief overview of the C library.
For a more detailed list of available functions, see the API documentation.
To report issues, ask questions, and request new features, use Github Issues
Design Basics
The library is written in C and is optimised for speed and portability.
All memory allocations take place in the new_ methods. Each successful call to new_ should have a matching call to del_ to deallocate the object.
// new_ to create an object foobar aubio_foobar_t * new_aubio_foobar(void * args); // del_ to delete foobar void del_aubio_foobar (aubio_foobar_t * foobar);
The main computations are done in the _do methods.
// _do to process output = foobar(input) audio_foobar_do (aubio_foobar_t * foobar, fvec_t * input, cvec_t * output);
Most parameters can be read and written at any time:
// _get_param to get foobar.param smpl_t aubio_foobar_get_a_parameter (aubio_foobar_t * foobar); // _set_param to set foobar.param uint_t aubio_foobar_set_a_parameter (aubio_foobar_t * foobar, smpl_t a_parameter);
In some case, more functions are available:
// non-real time functions uint_t aubio_foobar_reset(aubio_foobar_t * t);
Basic Types
// integers uint_t n = 10; // unsigned sint_t delay = -90; // signed // float smpl_t a = -90.; // simple precision lsmp_t f = 0.024; // double precision // vector of floats (simple precision) fvec_t * vec = new_fvec(n); vec->data[0] = 1; vec->data[vec->length-1] = 1.; // vec->data has n elements fvec_print(vec); del_fvec(vec); // complex data cvec_t * fftgrain = new_cvec(n); vec->norm[0] = 1.; // vec->norm has n/2+1 elements vec->phas[n/2] = 3.1415; // vec->phas as well del_cvec(fftgrain); // matrix fmat_t * mat = new_fmat (height, length); mat->data[height-1][0] = 1; // mat->data has height rows mat->data[0][length-1] = 10; // mat->data[0] has length columns del_fmat(mat);
Reading a sound file
In this example, aubio_source is used to read a media file.
First, define a few variables and allocate some memory.
.. literalinclude:: ../tests/src/io/test-source.c :language: C :lines: 22-24, 30-32, 34
Note
With samplerate = 0, aubio_source will be created with the file's original samplerate.
Now for the processing loop:
.. literalinclude:: ../tests/src/io/test-source.c :language: C :lines: 40-44
At the end of the processing loop, memory is deallocated:
.. literalinclude:: ../tests/src/io/test-source.c :language: C :lines: 55-56
See the complete example: :download:`test-source.c <../tests/src/io/test-source.c>`.
Computing a spectrum
Now let's create a phase vocoder:
.. literalinclude:: ../tests/src/spectral/test-phasevoc.c :language: C :lines: 6-11
The processing loop could now look like:
.. literalinclude:: ../tests/src/spectral/test-phasevoc.c :language: C :lines: 20-37
Time to clean up the previously allocated memory:
.. literalinclude:: ../tests/src/spectral/test-phasevoc.c :language: C :lines: 39-44
See the complete example: :download:`test-phasevoc.c <../tests/src/spectral/test-phasevoc.c>`.
Doxygen documentation
The latest version of the API documentation is built using Doxygen and is available at:
https://aubio.org/doc/latest/
Contribute
Please report any issue and feature request at the Github issue tracker. Patches and pull-requests welcome!
