48 lines
1.6 KiB
C++
48 lines
1.6 KiB
C++
/*
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* rms_detector.h
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* Copyright (c) 2025 Christopher Herb
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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#pragma once
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#include <cmath>
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namespace trnr {
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struct rms_detector {
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float alpha;
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float rms_squared;
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};
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inline void rms_init(rms_detector& d, float samplerate, float window_ms)
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{
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float window_seconds = 0.001f * window_ms;
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d.alpha = 1.0f - expf(-1.0f / (samplerate * window_seconds));
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d.rms_squared = 0.0f;
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}
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template <typename sample>
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inline sample rms_process(rms_detector& d, sample input)
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{
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d.rms_squared = (1.0f - d.alpha) * d.rms_squared + d.alpha * (input * input);
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return sqrtf(d.rms_squared);
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}
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} // namespace trnr
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