RealtimeResampler< T, NCHANS, A > Class Template Reference

A multi-channel real-time resampling container that can be used to resample audio processing to a specified sample rate for the situation where you have some arbitary DSP code that requires a specific rate. More...

#include <RealtimeResampler.h>

Public Types
enum class	ESRCMode { kLinearInterpolation = 0 , kLancsoz , kNumResamplingModes }
using	BlockProcessFunc = std::function< void(T **, T **, int, int)>
using	LanczosResampler = LanczosResampler< T, NCHANS, A >

Public Member Functions
	RealtimeResampler (double innerSampleRate, ESRCMode mode=ESRCMode::kLancsoz)
	Constructor. More...
	RealtimeResampler (const RealtimeResampler &)=delete
RealtimeResampler &	operator= (const RealtimeResampler &)=delete
void	Reset (double inputSampleRate, int maxBlockSize=DEFAULT_BLOCK_SIZE)
	Reset the underlying DSP (when the samplerate or max expected block size changes) More...
void	ProcessBlock (T **inputs, T **outputs, int nFrames, int nChans, BlockProcessFunc func)
	Resample an input block with a per-block function (resample input -> process with function -> resample back to external sample rate) More...
int	GetLatency () const
	Get the latency of the resampling, not including any latency of the encapsulated DSP. More...

Detailed Description

template<typename T = double, int NCHANS = 2, size_t A = 12>
class RealtimeResampler< T, NCHANS, A >

A multi-channel real-time resampling container that can be used to resample audio processing to a specified sample rate for the situation where you have some arbitary DSP code that requires a specific rate.

Two modes are supported:

• Linear interpolation: simple linear interpolation between samples
• Lanczos resampling uses an approximation of the sinc function to interpolate between samples. This is the highest quality resampling mode.

The Lanczos resampler has a configurable filter size (A) that affects the latency of the resampler. It can also optionally use SIMD instructions when T==float.

Template Parameters

T	the sampletype float or double
NCHANS	the number of channels
A	The Lanczos filter size for the LanczosResampler resampler mode A higher value makes the filter closer to an ideal stop-band that rejects high-frequency content (anti-aliasing), but at the expense of higher latency

Definition at line 44 of file RealtimeResampler.h.

Member Typedef Documentation

BlockProcessFunc

template<typename T = double, int NCHANS = 2, size_t A = 12>

using RealtimeResampler< T, NCHANS, A >::BlockProcessFunc = std::function<void(T**, T**, int, int)>

Definition at line 56 of file RealtimeResampler.h.

LanczosResampler

template<typename T = double, int NCHANS = 2, size_t A = 12>

using RealtimeResampler< T, NCHANS, A >::LanczosResampler = LanczosResampler<T, NCHANS, A>

Definition at line 57 of file RealtimeResampler.h.

Member Enumeration Documentation

ESRCMode

template<typename T = double, int NCHANS = 2, size_t A = 12>

enum class RealtimeResampler::ESRCMode

strong

Definition at line 49 of file RealtimeResampler.h.

Constructor & Destructor Documentation

RealtimeResampler()

template<typename T = double, int NCHANS = 2, size_t A = 12>

RealtimeResampler< T, NCHANS, A >::RealtimeResampler ( double  innerSampleRate, ESRCMode  mode = ESRCMode::kLancsoz  )

inline

Constructor.

Parameters

innerSampleRate	The sample rate that the provided DSP block will process at
mode	The sample rate conversion mode

Definition at line 63 of file RealtimeResampler.h.

Member Function Documentation

GetLatency()

template<typename T = double, int NCHANS = 2, size_t A = 12>

int RealtimeResampler< T, NCHANS, A >::GetLatency ( ) const

inline

Get the latency of the resampling, not including any latency of the encapsulated DSP.

Definition at line 174 of file RealtimeResampler.h.

ProcessBlock()

template<typename T = double, int NCHANS = 2, size_t A = 12>

void RealtimeResampler< T, NCHANS, A >::ProcessBlock ( T **  inputs, T **  outputs, int  nFrames, int  nChans, BlockProcessFunc  func  )

inline

Resample an input block with a per-block function (resample input -> process with function -> resample back to external sample rate)

Parameters

inputs	Two-dimensional array containing the non-interleaved input buffers of audio samples for all channels
outputs	Two-dimensional array for audio output (non-interleaved).
nFrames	The block size for this block: number of samples per channel.
func	The function that processes the audio sample at the higher sampling rate. NOTE: std::function can call malloc if you pass in captures

Definition at line 128 of file RealtimeResampler.h.

Reset()

template<typename T = double, int NCHANS = 2, size_t A = 12>

void RealtimeResampler< T, NCHANS, A >::Reset ( double  inputSampleRate, int  maxBlockSize = DEFAULT_BLOCK_SIZE  )

inline

Reset the underlying DSP (when the samplerate or max expected block size changes)

Parameters

inputSampleRate	The external sample rate interacting with this object.
maxBlockSize	The largest block size expected to be passed via nFrames in processBlock

Definition at line 76 of file RealtimeResampler.h.

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The documentation for this class was generated from the following file:

• RealtimeResampler.h