a999e40935
Apply envelope & panning after biquad filtering. This may fix the weird popping problem. It also reduces the number of operations that are done "in stereo", so it could help performance. It also fixes a previously unnoticed problem where a ring-modulated waveform had 2x the amplitude of an un-modulated waveform. The test differences look large but it's because some values got changed in the LSB after the mathematical divisions were moved around.
39 lines
1.6 KiB
C
39 lines
1.6 KiB
C
/*
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* This file is part of the Micro Python project, http://micropython.org/
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*
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* The MIT License (MIT)
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*
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* Copyright (c) 2023 Jeff Epler for Adafruit Industries
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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
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* THE SOFTWARE.
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*/
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#pragma once
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#include "py/obj.h"
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typedef struct {
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int32_t a1, a2, b0, b1, b2;
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int32_t x[2], y[2];
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} biquad_filter_state;
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void synthio_biquad_filter_assign(biquad_filter_state *st, mp_obj_t biquad_obj);
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void synthio_biquad_filter_reset(biquad_filter_state *st);
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void synthio_biquad_filter_samples(biquad_filter_state *st, int32_t *buffer, size_t n_samples);
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