fers_signal::DownsamplingSink Class Reference

Stateful FIR decimator for chunked streaming output. More...

#include "dsp_filters.h"

Public Member Functions
	DownsamplingSink ()
void	consume (std::span< const ComplexType > block)
void	finish ()
std::vector< ComplexType >	takeOutput ()
void	reset ()
std::uint64_t	inputSampleCount () const noexcept
std::uint64_t	outputSampleCount () const noexcept
unsigned	ratio () const noexcept

Detailed Description

Stateful FIR decimator for chunked streaming output.

This sink uses the same Blackman-windowed FIR design as downsample, but keeps filter history across input blocks and only zero-pads when finish() is called.

Definition at line 50 of file dsp_filters.h.

Constructor & Destructor Documentation

DownsamplingSink()

fers_signal::DownsamplingSink::DownsamplingSink

(

)

Definition at line 216 of file dsp_filters.cpp.

                                       : _ratio(params::oversampleRatio())
    {
        validateOversamplingConfig(_ratio);
        if (_ratio <= 1)
        {
            return;
        }
 
        const unsigned filter_length = params::renderFilterLength();
        const auto design = blackmanFir(1 / static_cast<RealType>(_ratio), _ratio, filter_length);
        _coeffs = design.coeffs;
        _line.assign(_coeffs.size(), ComplexType{0.0, 0.0});
        _delay = _coeffs.size() / 2u;
    }

References max, and params::renderFilterLength().

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Member Function Documentation

consume()

void fers_signal::DownsamplingSink::consume

(

std::span< const ComplexType >

block

)

Definition at line 231 of file dsp_filters.cpp.

    {
        if (_finished)
        {
            throw std::logic_error("Cannot consume downsampler input after finish");
        }
        if (block.empty())
        {
            return;
        }
 
        if (_ratio <= 1)
        {
            _pending.insert(_pending.end(), block.begin(), block.end());
            _input_sample_count += block.size();
            _processed_sample_count += block.size();
            _next_output_index += block.size();
            return;
        }
 
        for (const auto& sample : block)
        {
            const auto filtered = processOne(sample);
            ++_input_sample_count;
            maybeEmit(filtered);
            ++_processed_sample_count;
        }
    }

References max.

finish()

void fers_signal::DownsamplingSink::finish

(

)

Definition at line 260 of file dsp_filters.cpp.

    {
        if (_finished)
        {
            return;
        }
        _finished = true;
        if (_ratio <= 1)
        {
            return;
        }
 
        _target_output_count = _input_sample_count / _ratio;
        while (_next_output_index < _target_output_count)
        {
            const auto filtered = processOne(ComplexType{0.0, 0.0});
            maybeEmit(filtered);
            ++_processed_sample_count;
        }
    }

References max.

inputSampleCount()

std::uint64_t fers_signal::DownsamplingSink::inputSampleCount ( ) const

noexcept

Definition at line 60 of file dsp_filters.h.

{ return _input_sample_count; }

outputSampleCount()

std::uint64_t fers_signal::DownsamplingSink::outputSampleCount ( ) const

noexcept

Definition at line 61 of file dsp_filters.h.

{ return _next_output_index; }

ratio()

unsigned fers_signal::DownsamplingSink::ratio ( ) const

noexcept

Definition at line 62 of file dsp_filters.h.

{ return _ratio; }

reset()

void fers_signal::DownsamplingSink::reset

(

)

Definition at line 288 of file dsp_filters.cpp.

    {
        std::ranges::fill(_line, ComplexType{0.0, 0.0});
        _pending.clear();
        _input_sample_count = 0;
        _processed_sample_count = 0;
        _next_output_index = 0;
        _target_output_count = 0;
        _finished = false;
    }

takeOutput()

std::vector< ComplexType > fers_signal::DownsamplingSink::takeOutput

(

)

Definition at line 281 of file dsp_filters.cpp.

    {
        std::vector<ComplexType> out;
        out.swap(_pending);
        return out;
    }

References max.

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

• packages/libfers/src/signal/dsp_filters.h
• packages/libfers/src/signal/dsp_filters.cpp