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188 lines
7.0 KiB
188 lines
7.0 KiB
#ifdef SGTL5000_AUDIO_ENHANCE
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#include <Arduino.h>
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#include <Audio.h>
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extern AudioControlSGTL5000 sgtl5000_1;
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typedef struct biquad_coefficients_s {
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float32_t a0;
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float32_t a1;
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float32_t a2;
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float32_t b1;
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float32_t b2;
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} biquad_coefficients_t;
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typedef struct biquad_params_s {
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uint8_t filter_type;
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float32_t Fc;
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float32_t Q;
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} biquad_params_t;
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enum {
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bq_type_lowpass = 0,
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bq_type_highpass,
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bq_type_bandpass,
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bq_type_notch,
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bq_type_peak,
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bq_type_lowshelf,
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bq_type_highshelf
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};
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#define NUM_GRAPHIC_EQ_BANDS 7
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biquad_coefficients_t biquad_coefficients[NUM_GRAPHIC_EQ_BANDS];
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biquad_params_t biquad_params[NUM_GRAPHIC_EQ_BANDS];
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void set_sgtl5000_7band_eq(uint8_t band, uint8_t filter_type, float32_t Fc, float32_t Q);
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void set_sgtl5000_7band_eq_gain(uint8_t band, float32_t peakGainDB);
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void setup_sgtl5000_graphic_7band_eq(void);
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void calcBiquadCoefficients(biquad_coefficients_t* biquad_coefficients, uint8_t filter_type, float32_t Fc, float32_t Q, float32_t peakGain);
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void set_sgtl5000_7band_eq(uint8_t band, uint8_t filter_type, float32_t Fc, float32_t Q)
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{
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biquad_params[band].filter_type = filter_type;
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biquad_params[band].Fc = Fc;
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biquad_params[band].Q = Q;
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calcBiquadCoefficients(&biquad_coefficients[band], filter_type, Fc, Q, 0.0);
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//sgtl5000_1.eqFilter(band, biquad_coefficients);
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}
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void set_sgtl5000_7band_eq_gain(uint8_t band, float32_t peakGainDB)
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{
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calcBiquadCoefficients(&biquad_coefficients[band], biquad_params[band].filter_type, biquad_params[band].Fc, biquad_params[band].Q, peakGainDB);
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//sgtl5000_1.eqFilter(band, biquad_coefficients);
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}
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void setup_sgtl5000_graphic_7band_eq(void)
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{
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//sgtl5000_1.eqFilterCount(7); // enable 7 bands
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set_sgtl5000_7band_eq(0, GRAPHIC_EQ_TYPE_0, GRAPHIC_EQ_CENTER_FRQ_0, GRAPHIC_EQ_Q_0);
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set_sgtl5000_7band_eq(1, GRAPHIC_EQ_TYPE_1, GRAPHIC_EQ_CENTER_FRQ_1, GRAPHIC_EQ_Q_1);
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set_sgtl5000_7band_eq(2, GRAPHIC_EQ_TYPE_2, GRAPHIC_EQ_CENTER_FRQ_2, GRAPHIC_EQ_Q_2);
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set_sgtl5000_7band_eq(3, GRAPHIC_EQ_TYPE_3, GRAPHIC_EQ_CENTER_FRQ_3, GRAPHIC_EQ_Q_3);
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set_sgtl5000_7band_eq(4, GRAPHIC_EQ_TYPE_4, GRAPHIC_EQ_CENTER_FRQ_4, GRAPHIC_EQ_Q_4);
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set_sgtl5000_7band_eq(5, GRAPHIC_EQ_TYPE_5, GRAPHIC_EQ_CENTER_FRQ_5, GRAPHIC_EQ_Q_5);
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set_sgtl5000_7band_eq(6, GRAPHIC_EQ_TYPE_6, GRAPHIC_EQ_CENTER_FRQ_6, GRAPHIC_EQ_Q_6);
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}
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// Taken from https://www.earlevel.com/main/2012/11/26/biquad-c-source-code/
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//
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// Biquad.h
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//
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// Created by Nigel Redmon on 11/24/12
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// EarLevel Engineering: earlevel.com
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// Copyright 2012 Nigel Redmon
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//
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// For a complete explanation of the Biquad code:
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// http://www.earlevel.com/main/2012/11/25/biquad-c-source-code/
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//
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// License:
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//
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// This source code is provided as is, without warranty.
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// You may copy and distribute verbatim copies of this document.
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// You may modify and use this source code to create binary code
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// for your own purposes, free or commercial.
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//
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void calcBiquadCoefficients(biquad_coefficients_t* biquad_coefficients, uint8_t filter_type, float32_t Fc, float32_t Q, float32_t peakGain)
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{
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float32_t norm;
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float32_t V = pow(10, fabs(peakGain) / 20.0);
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float32_t K = tan(M_PI * Fc);
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switch (filter_type) {
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case bq_type_lowpass:
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norm = 1 / (1 + K / Q + K * K);
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biquad_coefficients->a0 = K * K * norm;
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biquad_coefficients->a1 = 2 * biquad_coefficients->a0;
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biquad_coefficients->a2 = biquad_coefficients->a0;
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biquad_coefficients->b1 = 2 * (K * K - 1) * norm;
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biquad_coefficients->b2 = (1 - K / Q + K * K) * norm;
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break;
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case bq_type_highpass:
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norm = 1 / (1 + K / Q + K * K);
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biquad_coefficients->a0 = 1 * norm;
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biquad_coefficients->a1 = -2 * biquad_coefficients->a0;
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biquad_coefficients->a2 = biquad_coefficients->a0;
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biquad_coefficients->b1 = 2 * (K * K - 1) * norm;
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biquad_coefficients->b2 = (1 - K / Q + K * K) * norm;
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break;
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case bq_type_bandpass:
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norm = 1 / (1 + K / Q + K * K);
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biquad_coefficients->a0 = K / Q * norm;
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biquad_coefficients->a1 = 0;
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biquad_coefficients->a2 = -biquad_coefficients->a0;
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biquad_coefficients->b1 = 2 * (K * K - 1) * norm;
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biquad_coefficients->b2 = (1 - K / Q + K * K) * norm;
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break;
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case bq_type_notch:
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norm = 1 / (1 + K / Q + K * K);
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biquad_coefficients->a0 = (1 + K * K) * norm;
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biquad_coefficients->a1 = 2 * (K * K - 1) * norm;
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biquad_coefficients->a2 = biquad_coefficients->a0;
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biquad_coefficients->b1 = biquad_coefficients->a1;
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biquad_coefficients->b2 = (1 - K / Q + K * K) * norm;
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break;
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case bq_type_peak:
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if (peakGain >= 0) { // boost
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norm = 1 / (1 + 1 / Q * K + K * K);
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biquad_coefficients->a0 = (1 + V / Q * K + K * K) * norm;
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biquad_coefficients->a1 = 2 * (K * K - 1) * norm;
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biquad_coefficients->a2 = (1 - V / Q * K + K * K) * norm;
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biquad_coefficients->b1 = biquad_coefficients->a1;
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biquad_coefficients->b2 = (1 - 1 / Q * K + K * K) * norm;
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}
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else { // cut
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norm = 1 / (1 + V / Q * K + K * K);
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biquad_coefficients->a0 = (1 + 1 / Q * K + K * K) * norm;
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biquad_coefficients->a1 = 2 * (K * K - 1) * norm;
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biquad_coefficients->a2 = (1 - 1 / Q * K + K * K) * norm;
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biquad_coefficients->b1 = biquad_coefficients->a1;
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biquad_coefficients->b2 = (1 - V / Q * K + K * K) * norm;
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}
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break;
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case bq_type_lowshelf:
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if (peakGain >= 0) { // boost
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norm = 1 / (1 + sqrt(2) * K + K * K);
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biquad_coefficients->a0 = (1 + sqrt(2 * V) * K + V * K * K) * norm;
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biquad_coefficients->a1 = 2 * (V * K * K - 1) * norm;
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biquad_coefficients->a2 = (1 - sqrt(2 * V) * K + V * K * K) * norm;
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biquad_coefficients->b1 = 2 * (K * K - 1) * norm;
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biquad_coefficients->b2 = (1 - sqrt(2) * K + K * K) * norm;
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}
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else { // cut
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norm = 1 / (1 + sqrt(2 * V) * K + V * K * K);
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biquad_coefficients->a0 = (1 + sqrt(2) * K + K * K) * norm;
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biquad_coefficients->a1 = 2 * (K * K - 1) * norm;
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biquad_coefficients->a2 = (1 - sqrt(2) * K + K * K) * norm;
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biquad_coefficients->b1 = 2 * (V * K * K - 1) * norm;
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biquad_coefficients->b2 = (1 - sqrt(2 * V) * K + V * K * K) * norm;
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}
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break;
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case bq_type_highshelf:
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if (peakGain >= 0) { // boost
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norm = 1 / (1 + sqrt(2) * K + K * K);
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biquad_coefficients->a0 = (V + sqrt(2 * V) * K + K * K) * norm;
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biquad_coefficients->a1 = 2 * (K * K - V) * norm;
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biquad_coefficients->a2 = (V - sqrt(2 * V) * K + K * K) * norm;
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biquad_coefficients->b1 = 2 * (K * K - 1) * norm;
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biquad_coefficients->b2 = (1 - sqrt(2) * K + K * K) * norm;
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}
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else { // cut
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norm = 1 / (V + sqrt(2 * V) * K + K * K);
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biquad_coefficients->a0 = (1 + sqrt(2) * K + K * K) * norm;
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biquad_coefficients->a1 = 2 * (K * K - 1) * norm;
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biquad_coefficients->a2 = (1 - sqrt(2) * K + K * K) * norm;
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biquad_coefficients->b1 = 2 * (K * K - V) * norm;
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biquad_coefficients->b2 = (V - sqrt(2 * V) * K + K * K) * norm;
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}
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break;
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}
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return;
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}
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#endif
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