Main user functions

Functions
size_t	onsetsds_memneeded (int odftype, size_t fftsize, unsigned int medspan)
void	onsetsds_init (OnsetsDS *ods, float *odsdata, int fftformat, int odftype, size_t fftsize, unsigned int medspan, float srate)
bool	onsetsds_process (OnsetsDS *ods, float *fftbuf)

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Function Documentation

size_t onsetsds_memneeded	(	int	odftype,
		size_t	fftsize,
		unsigned int	medspan
	)

Determine how many bytes of memory must be allocated (e.g. using malloc) to accompany the OnsetsDS struct, operating using the specified settings (used to store part-processed FFT data etc). The user must call this, and then allocate the memory, BEFORE calling onsetsds_init().

Parameters:

	odftype	Which onset detection function (ODF) you'll be using, chosen from onsetsds_odf_types
	fftsize	Size of FFT: 512 is recommended.
	medspan	The number of past frames that will be used for median calculation during triggering

void onsetsds_init	(	OnsetsDS *	ods,
		float *	odsdata,
		int	fftformat,
		int	odftype,
		size_t	fftsize,
		unsigned int	medspan,
		float	srate
	)

Initialise the OnsetsDS struct and its associated memory, ready to detect onsets using the specified settings. Must be called before any call to onsetsds_process().

Note: you can change the onset detection function type in mid-operation by calling onsetsds_init() again, but because memory will be reset this will behave as if starting from scratch (rather than being aware of the past few frames of sound). Do not attempt to change the onset detection function in a more hacky way (e.g. fiddling with the struct) because memory is set up differently for each of the different ODFs.

Parameters:

	ods	An instance of the OnsetsDS struct
	odsdata	A pointer to the memory allocated, size given by onsetsds_memneeded().
	fftformat	Which format of FFT data is to be expected, chosen from onsetsds_fft_types
	odftype	Which onset detection function (ODF) you'll be using, chosen from onsetsds_odf_types
	fftsize	Size of FFT: 512 or 1024 is recommended.
	medspan	The number of past frames that will be used for median calculation during triggering
	srate	The sampling rate of the input audio

bool onsetsds_process	(	OnsetsDS *	ods,
		float *	fftbuf
	)

Process a single FFT data frame in the audio signal. Note that processing assumes that each call to onsetsds_process() is on a subsequent frame in the same audio stream - to handle multiple streams you must use separate OnsetsDS structs and memory!

This function's main purpose is to call some of the library's other functions, in the expected sequence.