include/libresample.h File Reference

libresample API More...

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Functions
void *	resample_open (int highQuality, double minFactor, double maxFactor)
	Create a resampler.
void *	resample_dup (const void *handle)
	Duplicate a resampler.
int	resample_get_filter_width (const void *handle)
	Get filter width for resampler.
int	resample_process (void *handle, double factor, float *inBuffer, int inBufferLen, int lastFlag, int *inBufferUsed, float *outBuffer, int outBufferLen)
	Resample a chunk of audio.
void	resample_close (void *handle)
	Close a resampler.

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Detailed Description

libresample API

Author:

Dominic Mazzoni

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Function Documentation

void resample_close

(

void *

handle

)

Close a resampler.

Parameters:

handle

the resampler to close

Use this function to release a handle to a resampler that was created using either resample_open() or resample_dup().

Returns:

nothing.

void* resample_dup

(

const void *

handle

)

Duplicate a resampler.

Parameters:

handle

the resampler to duplicate

Returns:

A new handle to a resampler, initialized with the same parameters used to create the original resampler.

int resample_get_filter_width

(

const void *

handle

)

Get filter width for resampler.

Parameters:

handle

the resampler

Returns:

the filter width.

void* resample_open	(	int	highQuality,
		double	minFactor,
		double	maxFactor
	)

Create a resampler.

Parameters:

highQuality	Set this argument to non-zero to enable higher quality resampling.
minFactor	This is the minimum resampling factor that will be used for this resampler. The resampling factor is calculated in the following way: ( from sample rate / to sample rate ).
maxFactor	This is the maximum resampling factor that will be used for this resampler.

Use this function to create a new resampler that will maintain state information about the stream of audio being resampled.

Returns:

A handle to a new resampler

int resample_process	(	void *	handle,
		double	factor,
		float *	inBuffer,
		int	inBufferLen,
		int	lastFlag,
		int *	inBufferUsed,
		float *	outBuffer,
		int	outBufferLen
	)

Resample a chunk of audio.

Parameters:

handle	the resampler
factor	the resampling factor. This factor should be calculated as ( from sample rate / to sample rate ). So, for converting from 8 kHz to 16 kHz, this value would be 2.0.
inBuffer	the input buffer for audio to resample.
inBufferLen	the number of samples in the input buffer
lastFlag	Set this argument to non-zero if the data in the input buffer is known to be the end of a stream. This would be used if you're resampling a file, for example.
inBufferUsed	This is an output parameter that indicates how many samples were consumed from the input buffer. Generally, this function is called in a loop until you know that the entire input buffer has been consumed, as it may take multiple calls to complete.
outBuffer	This is the output buffer. This function will write the resampled audio into this buffer.
outBufferLen	This parameter specifies how many samples there is room for in the output buffer.

This is the main function used for resampling audio. It should be called in a loop until all of the data from the input buffer is consumed, or the output buffer has been filled.

Returns:

the number of samples written to the output buffer. If the return value is equal to the value provided in the outBufferLen parameter, then the output buffer has been filled.