56 lines
1.3 KiB
C++
56 lines
1.3 KiB
C++
#pragma once
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#include <nall/queue.hpp>
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namespace nall { namespace DSP { namespace Resampler {
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struct Cubic {
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inline auto reset(double inputFrequency, double outputFrequency, uint queueSize = 0) -> void;
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inline auto pending() const -> bool { return samples.pending(); }
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inline auto read() -> double { return samples.read(); }
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inline auto write(double sample) -> void;
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private:
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double inputFrequency;
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double outputFrequency;
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double ratio;
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double fraction;
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double history[4];
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queue<double> samples;
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};
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auto Cubic::reset(double inputFrequency, double outputFrequency, uint queueSize) -> void {
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this->inputFrequency = inputFrequency;
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this->outputFrequency = outputFrequency;
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if(!queueSize) queueSize = outputFrequency * 0.02; //20ms
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ratio = inputFrequency / outputFrequency;
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fraction = 0.0;
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for(auto& sample: history) sample = 0.0;
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samples.resize(queueSize);
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}
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auto Cubic::write(double sample) -> void {
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auto& mu = fraction;
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auto& s = history;
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s[0] = s[1];
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s[1] = s[2];
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s[2] = s[3];
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s[3] = sample;
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while(mu <= 1.0) {
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double A = s[3] - s[2] - s[0] + s[1];
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double B = s[0] - s[1] - A;
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double C = s[2] - s[0];
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double D = s[1];
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samples.write(A * mu * mu * mu + B * mu * mu + C * mu + D);
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mu += ratio;
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}
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mu -= 1.0;
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}
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}}}
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