Class samplerate_converter¶

`class` samplerate_converter<T> dsp ¶

template <typename T>
struct samplerate_converter { … }

A template class for performing sample rate conversion on audio signals.

This class supports both push and pull methods for resampling audio data. It maintains an internal state to handle contiguous signals split into buffers of varying sizes.

Template parameters
T	The data type of the audio samples (e.g., float, double).

`typedef` itype ¶

using itype = i64

Fully qualified name: kfr::samplerate_converter<T>::itype

Declared at dsp/sample_rate_conversion.hpp:69

`typedef` ftype ¶

using ftype = subtype<T>

Fully qualified name: kfr::samplerate_converter<T>::ftype

Declared at dsp/sample_rate_conversion.hpp:70

`function` window(fbase) ¶

Computes the Kaiser window function for a given sample position.

Parameters
n	Normalized sample position.

Returns
	The window value.

Fully qualified name: kfr::samplerate_converter<T>::window(fbase)

Declared at dsp/sample_rate_conversion.hpp:78

`function` sidelobe_att() ¶

Calculates the sidelobe attenuation based on the Kaiser beta parameter.

Returns
	Sidelobe attenuation in dB.

Fully qualified name: kfr::samplerate_converter<T>::sidelobe_att()

Declared at dsp/sample_rate_conversion.hpp:87

`function` transition_width() ¶

Calculates the transition width based on sidelobe attenuation and depth.

Returns
	Transition width in radians.

Fully qualified name: kfr::samplerate_converter<T>::transition_width()

Declared at dsp/sample_rate_conversion.hpp:93

`function` reset() ¶

void reset() noexcept

Resets the converter to its initial state.

Fully qualified name: kfr::samplerate_converter<T>::reset()

Declared at dsp/sample_rate_conversion.hpp:106

`function` filter_order(sample_rate_conversion_quality) ¶

static KFR_MEM_INTRINSIC size_t filter_order(sample_rate_conversion_quality quality)

Computes the filter order for a given quality level.

Parameters
quality	The sample rate conversion quality.

Returns
	The filter order as a size_t.

Fully qualified name: kfr::samplerate_converter<T>::filter_order(sample_rate_conversion_quality)

Declared at dsp/sample_rate_conversion.hpp:118

`function` sidelobe_attenuation(sample_rate_conversion_quality) ¶

static KFR_MEM_INTRINSIC fbase sidelobe_attenuation(sample_rate_conversion_quality quality)

Returns the sidelobe attenuation for a given quality level.

Parameters
quality	The sample rate conversion quality.

Returns
	Sidelobe attenuation in dB.

Fully qualified name: kfr::samplerate_converter<T>::sidelobe_attenuation(sample_rate_conversion_quality)

Declared at dsp/sample_rate_conversion.hpp:128

`function` transition_width(sample_rate_conversion_quality) ¶

static KFR_MEM_INTRINSIC fbase transition_width(sample_rate_conversion_quality quality)

Returns the transition width for a given quality level.

Parameters
quality	The sample rate conversion quality.

Returns
	Transition width in radians.

Fully qualified name: kfr::samplerate_converter<T>::transition_width(sample_rate_conversion_quality)

Declared at dsp/sample_rate_conversion.hpp:138

`function` window_param(sample_rate_conversion_quality) ¶

static KFR_MEM_INTRINSIC fbase window_param(sample_rate_conversion_quality quality)

Computes the Kaiser window parameter for a given quality level.

Parameters
quality	The sample rate conversion quality.

Returns
	The Kaiser beta parameter.

Fully qualified name: kfr::samplerate_converter<T>::window_param(sample_rate_conversion_quality)

Declared at dsp/sample_rate_conversion.hpp:148

`function` window_param(fbase) ¶

static KFR_MEM_INTRINSIC fbase window_param(fbase att)

Fully qualified name: kfr::samplerate_converter<T>::window_param(fbase)

Declared at dsp/sample_rate_conversion.hpp:152

`constructor` samplerate_converter<T>(sample_rate_conversion_quality, itype, itype, fbase, fbase) ¶

samplerate_converter(sample_rate_conversion_quality quality, itype interpolation_factor,
                     itype decimation_factor, fbase scale = ftype(1), fbase cutoff = 0.5f)

Constructs a sample rate converter.

Parameters
quality	The desired conversion quality.
interpolation_factor	Factor by which to interpolate the input signal.
decimation_factor	Factor by which to decimate the output signal.
scale	Scaling factor for the output (default: 1).
cutoff	Cutoff frequency as a fraction of the Nyquist frequency (default: 0.5).

Fully qualified name: kfr::samplerate_converter<T>::samplerate_converter<T>(sample_rate_conversion_quality, itype, itype, fbase, fbase)

Declared at dsp/sample_rate_conversion.hpp:169

`constructor` samplerate_converter<T>(int, itype, itype, fbase, fbase, fbase, fbase) ¶

samplerate_converter(int taps, itype interpolation_factor, itype decimation_factor, fbase scale,
                     fbase cutoff, fbase sidelobe_attenuation, fbase transition_width)

Constructs a sample rate converter from explicit filter parameters.

Parameters
taps	Number of taps per polyphase branch (processing depth).
interpolation_factor	Factor by which to interpolate the input signal.
decimation_factor	Factor by which to decimate the output signal.
scale	Scaling factor applied to the output.
cutoff	Cutoff frequency as a fraction of the Nyquist frequency.
sidelobe_attenuation	Sidelobe attenuation in dB used to derive the Kaiser window.
transition_width	Transition width in radians used to adjust the cutoff.

Fully qualified name: kfr::samplerate_converter<T>::samplerate_converter<T>(int, itype, itype, fbase, fbase, fbase, fbase)

Declared at dsp/sample_rate_conversion.hpp:182

`constructor` samplerate_converter<T>() ¶

samplerate_converter() = default

Default constructor.

Fully qualified name: kfr::samplerate_converter<T>::samplerate_converter<T>()

Declared at dsp/sample_rate_conversion.hpp:193

`constructor` samplerate_converter<T>(samplerate_converter<T> &&) ¶

samplerate_converter(samplerate_converter&&) noexcept = default

Move constructor.

Fully qualified name: kfr::samplerate_converter<T>::samplerate_converter<T>(samplerate_converter<T> &&)

Declared at dsp/sample_rate_conversion.hpp:202

`function` operator=(samplerate_converter<T> &&) ¶

samplerate_converter& operator=(samplerate_converter&&) noexcept = default

Move assignment operator.

Parameters
other	The converter to move from.

Returns
	A reference to `*this` .

Fully qualified name: kfr::samplerate_converter<T>::operator=(samplerate_converter<T> &&)

Declared at dsp/sample_rate_conversion.hpp:214

`function` input_position_to_intermediate(itype) ¶

Converts an input position to an intermediate (interpolated) position.

The intermediate domain is the high-rate domain obtained after interpolation and before decimation. This maps an input sample index to its corresponding index in that domain.

Parameters
in_pos	Input position.

Returns
	Intermediate position `in_pos * interpolation_factor` .

Fully qualified name: kfr::samplerate_converter<T>::input_position_to_intermediate(itype)

Declared at dsp/sample_rate_conversion.hpp:225

`function` output_position_to_intermediate(itype) ¶

Converts an output position to an intermediate (pre-decimation) position.

Maps an output sample index back to its corresponding index in the high-rate intermediate domain.

Parameters
out_pos	Output position.

Returns
	Intermediate position `out_pos * decimation_factor` .

Fully qualified name: kfr::samplerate_converter<T>::output_position_to_intermediate(itype)

Declared at dsp/sample_rate_conversion.hpp:238

`function` input_position_to_output(itype) ¶

Converts an input position to the corresponding output position.

Uses floor division of the intermediate position by the decimation factor, so the result is the index of the output sample that consumes the given input sample (or the last output sample produced at or before it).

Parameters
in_pos	Input position.

Returns
	Corresponding output position.

Fully qualified name: kfr::samplerate_converter<T>::input_position_to_output(itype)

Declared at dsp/sample_rate_conversion.hpp:252

`function` output_position_to_input(itype) ¶

Converts an output position to the corresponding input position.

Uses floor division of the intermediate position by the interpolation factor, so the result is the index of the input sample needed to produce the given output sample.

Parameters
out_pos	Output position.

Returns
	Corresponding input position.

Fully qualified name: kfr::samplerate_converter<T>::output_position_to_input(itype)

Declared at dsp/sample_rate_conversion.hpp:266

`function` output_size_for_input(itype) ¶

Calculates the output size produced for a given input size (push method).

Parameters
input_size	Size of the input buffer.

Returns
	Required output buffer size.

Fully qualified name: kfr::samplerate_converter<T>::output_size_for_input(itype)

Declared at dsp/sample_rate_conversion.hpp:280

`function` input_size_for_output(itype) ¶

Calculates the input size required to produce a given output size (pull method).

Parameters
output_size	Size of the output buffer.

Returns
	Required input buffer size.

Fully qualified name: kfr::samplerate_converter<T>::input_size_for_output(itype)

Declared at dsp/sample_rate_conversion.hpp:295

`function` skip(size_t, univector_ref<const T>) ¶

size_t skip(size_t output_size, univector_ref<const T> input)

Skips a specified number of output samples, updating internal state.

Parameters
output_size	Number of output samples to skip.
input	Input buffer to consume.

Returns
	Number of input samples consumed.

Fully qualified name: kfr::samplerate_converter<T>::skip(size_t, univector_ref<const T>)

Declared at dsp/sample_rate_conversion.hpp:313

`function` process(univector<T, Tag> &, univector_ref<const T>) ¶

template <univector_tag Tag>
size_t process(univector<T, Tag>& output, univector_ref<const T> input)

Processes input data to produce resampled output (pull or push method).

Template parameters
Tag	Type tag for the univector output.

Parameters
output	Output buffer to write resampled data.
input	Input buffer to read samples from.

Returns
	Number of input samples processed.

Fully qualified name: kfr::samplerate_converter<T>::process(univector<T, Tag> &, univector_ref<const T>)

Declared at dsp/sample_rate_conversion.hpp:347

`function` get_fractional_delay() ¶

Gets the fractional delay introduced by the resampler.

The delay is the group delay of the symmetric FIR filter, expressed in output-sample units.

Returns
	Fractional delay in output samples.

Fully qualified name: kfr::samplerate_converter<T>::get_fractional_delay()

Declared at dsp/sample_rate_conversion.hpp:359

`function` get_delay() ¶

Gets the integer delay introduced by the resampler.

Returns
	Delay in output samples.

Fully qualified name: kfr::samplerate_converter<T>::get_delay()

Declared at dsp/sample_rate_conversion.hpp:369

`variable` kaiser_beta ¶

fbase kaiser_beta

Kaiser window beta parameter.

Fully qualified name: kfr::samplerate_converter<T>::kaiser_beta

Declared at dsp/sample_rate_conversion.hpp:371

`variable` depth ¶

itype depth

Processing depth.

Fully qualified name: kfr::samplerate_converter<T>::depth

Declared at dsp/sample_rate_conversion.hpp:372

`variable` taps ¶

itype taps

Number of filter taps.

Fully qualified name: kfr::samplerate_converter<T>::taps

Declared at dsp/sample_rate_conversion.hpp:373

`variable` order ¶

size_t order

Filter order.

Fully qualified name: kfr::samplerate_converter<T>::order

Declared at dsp/sample_rate_conversion.hpp:374

`variable` interpolation_factor ¶

itype interpolation_factor

Interpolation factor.

Fully qualified name: kfr::samplerate_converter<T>::interpolation_factor

Declared at dsp/sample_rate_conversion.hpp:375

`variable` decimation_factor ¶

itype decimation_factor

Decimation factor.

Fully qualified name: kfr::samplerate_converter<T>::decimation_factor

Declared at dsp/sample_rate_conversion.hpp:376

`variable` filter ¶

univector<T> filter

Filter coefficients.

Fully qualified name: kfr::samplerate_converter<T>::filter

Declared at dsp/sample_rate_conversion.hpp:377

`variable` delay ¶

univector<T> delay

Delay line buffer.

Fully qualified name: kfr::samplerate_converter<T>::delay

Declared at dsp/sample_rate_conversion.hpp:378

`variable` input_position ¶

itype input_position

Current input position.

Fully qualified name: kfr::samplerate_converter<T>::input_position

Declared at dsp/sample_rate_conversion.hpp:381

`variable` output_position ¶

itype output_position

Current output position.

Fully qualified name: kfr::samplerate_converter<T>::output_position

Declared at dsp/sample_rate_conversion.hpp:382

`function` process_impl(univector_ref<T>, univector_ref<const T>) ¶

size_t process_impl(univector_ref<T> output, univector_ref<const T> input)

Internal implementation of the process function.

Parameters
output	Output buffer slice.
input	Input buffer slice.

Returns
	Number of input samples processed.

Fully qualified name: kfr::samplerate_converter<T>::process_impl(univector_ref<T>, univector_ref<const T>)

Declared at dsp/sample_rate_conversion.hpp:390

Fully qualified name: kfr::samplerate_converter<T>

Declared at dsp/sample_rate_conversion.hpp:67

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Class samplerate_converter¶