audio_reactive.h

#pragma once

/* 
   @title     MoonModules WLED - audioreactive usermod
   @file      audio_reactive.h
   @repo      https://github.com/MoonModules/WLED, submit changes to this file as PRs to MoonModules/WLED
   @Authors   https://github.com/MoonModules/WLED/commits/mdev/
   @Copyright © 2024 Github MoonModules Commit Authors (contact moonmodules@icloud.com for details)
   @license   GNU GENERAL PUBLIC LICENSE Version 3, 29 June 2007

     This file is part of the MoonModules WLED fork also known as "WLED-MM".
     WLED-MM is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License 
     as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

     WLED-MM is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied 
     warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
     
     You should have received a copy of the GNU General Public License along with WLED-MM. If not, see <https://www.gnu.org/licenses/>.
*/


#include "wled.h"

#ifdef ARDUINO_ARCH_ESP32

#include <driver/i2s.h>
#include <driver/adc.h>

#include <math.h>
#endif

#if defined(ARDUINO_ARCH_ESP32) && (defined(WLED_DEBUG) || defined(SR_DEBUG))
#include <esp_timer.h>
#endif

/*
 * Usermods allow you to add own functionality to WLED more easily
 * See: https://github.com/Aircoookie/WLED/wiki/Add-own-functionality
 * 
 * This is an audioreactive v2 usermod.
 * ....
 */

#define FFT_PREFER_EXACT_PEAKS  // use different FFT windowing -> results in "sharper" peaks and less "leaking" into other frequencies
//#define SR_STATS

#if !defined(FFTTASK_PRIORITY)
#if defined(WLEDMM_FASTPATH) && !defined(CONFIG_IDF_TARGET_ESP32S2) && !defined(CONFIG_IDF_TARGET_ESP32C3) && defined(ARDUINO_ARCH_ESP32)
// FASTPATH: use higher priority, to avoid that webserver (ws, json, etc) delays sample processing
//#define FFTTASK_PRIORITY 3 // competing with async_tcp
#define FFTTASK_PRIORITY 4   // above async_tcp
#else
#define FFTTASK_PRIORITY 1 // standard: looptask prio
//#define FFTTASK_PRIORITY 2 // above looptask, below async_tcp
#endif
#endif

#if !defined(CONFIG_IDF_TARGET_ESP32S2) && !defined(CONFIG_IDF_TARGET_ESP32C3)
// this applies "pink noise scaling" to FFT results before computing the major peak for effects.
// currently only for ESP32-S3 and classic ESP32, due to increased runtime
#define FFT_MAJORPEAK_HUMAN_EAR
#endif

// high-resolution type for input filters
#if defined(ARDUINO_ARCH_ESP32) && !defined(CONFIG_IDF_TARGET_ESP32S2) && !defined(CONFIG_IDF_TARGET_ESP32C3)
#define SR_HIRES_TYPE double  // ESP32 and ESP32-S3 (with FPU) are fast enough to use "double"
#else
#define SR_HIRES_TYPE float   // prefer faster type on slower boards (-S2, -C3)
#endif

// Comment/Uncomment to toggle usb serial debugging
// #define MIC_LOGGER                   // MIC sampling & sound input debugging (serial plotter)
// #define FFT_SAMPLING_LOG             // FFT result debugging
// #define SR_DEBUG                     // generic SR DEBUG messages

#ifdef SR_DEBUG
  #define DEBUGSR_PRINT(x) DEBUGOUT(x)
  #define DEBUGSR_PRINTLN(x) DEBUGOUTLN(x)
  #define DEBUGSR_PRINTF(x...) DEBUGOUTF(x)
#else
  #define DEBUGSR_PRINT(x)
  #define DEBUGSR_PRINTLN(x)
  #define DEBUGSR_PRINTF(x...)
#endif

#if defined(SR_DEBUG)
#define ERRORSR_PRINT(x) DEBUGSR_PRINT(x)
#define ERRORSR_PRINTLN(x) DEBUGSR_PRINTLN(x)
#define ERRORSR_PRINTF(x...) DEBUGSR_PRINTF(x)
#else
#if defined(WLED_DEBUG)
#define ERRORSR_PRINT(x) DEBUG_PRINT(x)
#define ERRORSR_PRINTLN(x) DEBUG_PRINTLN(x)
#define ERRORSR_PRINTF(x...) DEBUG_PRINTF(x)
#else
  #define ERRORSR_PRINT(x)
  #define ERRORSR_PRINTLN(x)
  #define ERRORSR_PRINTF(x...)
#endif
#endif

#if defined(MIC_LOGGER) || defined(FFT_SAMPLING_LOG)
  #define PLOT_PRINT(x) DEBUGOUT(x)
  #define PLOT_PRINTLN(x) DEBUGOUTLN(x)
  #define PLOT_PRINTF(x...) DEBUGOUTF(x)
  #define PLOT_FLUSH() DEBUGOUTFlush()
#else
  #define PLOT_PRINT(x)
  #define PLOT_PRINTLN(x)
  #define PLOT_PRINTF(x...)
  #define PLOT_FLUSH()
#endif

// sanity checks
#ifdef ARDUINO_ARCH_ESP32
  // we need more space in for oappend() stack buffer -> SETTINGS_STACK_BUF_SIZE and CONFIG_ASYNC_TCP_TASK_STACK_SIZE
  #if SETTINGS_STACK_BUF_SIZE < 3904    // 3904 is required for WLEDMM-0.14.0-b28
    #warning please increase SETTINGS_STACK_BUF_SIZE >= 3904
  #endif
  #if (CONFIG_ASYNC_TCP_TASK_STACK_SIZE - SETTINGS_STACK_BUF_SIZE) < 4352 // at least 4096+256 words of free task stack is needed by async_tcp alone
    #error remaining async_tcp stack will be too low - please increase CONFIG_ASYNC_TCP_TASK_STACK_SIZE
  #endif
#endif

// audiosync constants
#define AUDIOSYNC_NONE 0x00      // UDP sound sync off
#define AUDIOSYNC_SEND 0x01      // UDP sound sync - send mode
#define AUDIOSYNC_REC  0x02      // UDP sound sync - receiver mode
#define AUDIOSYNC_REC_PLUS 0x06  // UDP sound sync - receiver + local mode (uses local input if no receiving udp sound)
#define AUDIOSYNC_IDLE_MS  2500  // timeout for "receiver idle" (milliseconds) 

static volatile bool disableSoundProcessing = false;      // if true, sound processing (FFT, filters, AGC) will be suspended. "volatile" as its shared between tasks.
static uint8_t audioSyncEnabled = AUDIOSYNC_NONE;         // bit field: bit 0 - send, bit 1 - receive, bit 2 - use local if not receiving
static bool audioSyncSequence = true;                     // if true, the receiver will drop out-of-sequence packets
static bool udpSyncConnected = false;         // UDP connection status -> true if connected to multicast group

#define NUM_GEQ_CHANNELS 16                                           // number of frequency channels. Don't change !!

// audioreactive variables
#ifdef ARDUINO_ARCH_ESP32
static float    micDataReal = 0.0f;             // MicIn data with full 24bit resolution - lowest 8bit after decimal point
static float    multAgc = 1.0f;                 // sample * multAgc = sampleAgc. Our AGC multiplier
static float    sampleAvg = 0.0f;               // Smoothed Average sample - sampleAvg < 1 means "quiet" (simple noise gate)
static float    sampleAgc = 0.0f;               // Smoothed AGC sample
#ifdef SR_SQUELCH
static uint8_t  soundAgc = 1;                   // Automagic gain control: 0 - none, 1 - normal, 2 - vivid, 3 - lazy (config value) - enable AGC if default "squelch" was provided
#else
static uint8_t  soundAgc = 0;                   // Automagic gain control: 0 - none, 1 - normal, 2 - vivid, 3 - lazy (config value)
#endif

#endif
static float    volumeSmth = 0.0f;              // either sampleAvg or sampleAgc depending on soundAgc; smoothed sample
static float FFT_MajorPeak = 1.0f;              // FFT: strongest (peak) frequency
static float FFT_Magnitude = 0.0f;              // FFT: volume (magnitude) of peak frequency
static bool samplePeak = false;      // Boolean flag for peak - used in effects. Responding routine may reset this flag. Auto-reset after strip.getMinShowDelay()
static bool udpSamplePeak = false;   // Boolean flag for peak. Set at the same time as samplePeak, but reset by transmitAudioData
static unsigned long timeOfPeak = 0; // time of last sample peak detection.
volatile bool haveNewFFTResult = false; // flag to directly inform UDP sound sender when new FFT results are available (to reduce latency). Flag is reset at next UDP send

static uint8_t fftResult[NUM_GEQ_CHANNELS]= {0};   // Our calculated freq. channel result table to be used by effects
static float   fftCalc[NUM_GEQ_CHANNELS] = {0.0f}; // Try and normalize fftBin values to a max of 4096, so that 4096/16 = 256. (also used by dynamics limiter)
static float   fftAvg[NUM_GEQ_CHANNELS] = {0.0f};  // Calculated frequency channel results, with smoothing (used if dynamics limiter is ON)

static uint16_t zeroCrossingCount = 0; // number of zero crossings in the current batch of 512 samples

// TODO: probably best not used by receive nodes
static float agcSensitivity = 128;            // AGC sensitivity estimation, based on agc gain (multAgc). calculated by getSensitivity(). range 0..255

// user settable parameters for limitSoundDynamics()
#ifdef UM_AUDIOREACTIVE_DYNAMICS_LIMITER_OFF
static bool limiterOn = false;                 // bool: enable / disable dynamics limiter
#else
static bool limiterOn = true;
#endif
static uint16_t attackTime = 50;              // int: attack time in milliseconds. Default 0.08sec
static uint16_t decayTime = 300;              // int: decay time in milliseconds.  New default 300ms. Old default was 1.40sec

// peak detection
#ifdef ARDUINO_ARCH_ESP32
static void detectSamplePeak(void);  // peak detection function (needs scaled FFT results in vReal[]) - no used for 8266 receive-only mode
#endif
static void autoResetPeak(void);     // peak auto-reset function
static uint8_t maxVol = 31;          // (was 10) Reasonable value for constant volume for 'peak detector', as it won't always trigger  (deprecated)
static uint8_t binNum = 8;           // Used to select the bin for FFT based beat detection  (deprecated)

#ifdef ARDUINO_ARCH_ESP32

// use audio source class (ESP32 specific)
#include "audio_source.h"
constexpr i2s_port_t I2S_PORT = I2S_NUM_0;       // I2S port to use (do not change !)
constexpr int BLOCK_SIZE = 128;                  // I2S buffer size (samples)

// globals
static uint8_t inputLevel = 128;              // UI slider value
#ifndef SR_SQUELCH
  uint8_t soundSquelch = 10;                  // squelch value for volume reactive routines (config value)
#else
  uint8_t soundSquelch = SR_SQUELCH;          // squelch value for volume reactive routines (config value)
#endif
#ifndef SR_GAIN
  uint8_t sampleGain = 60;                    // sample gain (config value)
#else
  uint8_t sampleGain = SR_GAIN;               // sample gain (config value)
#endif

// user settable options for FFTResult scaling
static uint8_t FFTScalingMode = 3;            // 0 none; 1 optimized logarithmic; 2 optimized linear; 3 optimized square root
#ifndef SR_FREQ_PROF
  static uint8_t pinkIndex = 0;               // 0: default; 1: line-in; 2: IMNP441
#else
  static uint8_t pinkIndex = SR_FREQ_PROF;    // 0: default; 1: line-in; 2: IMNP441
#endif


// 
// AGC presets
//  Note: in C++, "const" implies "static" - no need to explicitly declare everything as "static const"
// 
#define AGC_NUM_PRESETS 3 // AGC presets:          normal,   vivid,    lazy
const double agcSampleDecay[AGC_NUM_PRESETS]  = { 0.9994f, 0.9985f, 0.9997f}; // decay factor for sampleMax, in case the current sample is below sampleMax
const float agcZoneLow[AGC_NUM_PRESETS]       = {      32,      28,      36}; // low volume emergency zone
const float agcZoneHigh[AGC_NUM_PRESETS]      = {     240,     240,     248}; // high volume emergency zone
const float agcZoneStop[AGC_NUM_PRESETS]      = {     336,     448,     304}; // disable AGC integrator if we get above this level
const float agcTarget0[AGC_NUM_PRESETS]       = {     112,     144,     164}; // first AGC setPoint -> between 40% and 65%
const float agcTarget0Up[AGC_NUM_PRESETS]     = {      88,      64,     116}; // setpoint switching value (a poor man's bang-bang)
const float agcTarget1[AGC_NUM_PRESETS]       = {     220,     224,     216}; // second AGC setPoint -> around 85%
const double agcFollowFast[AGC_NUM_PRESETS]   = { 1/192.f, 1/128.f, 1/256.f}; // quickly follow setpoint - ~0.15 sec
const double agcFollowSlow[AGC_NUM_PRESETS]   = {1/6144.f,1/4096.f,1/8192.f}; // slowly follow setpoint  - ~2-15 secs
const double agcControlKp[AGC_NUM_PRESETS]    = {    0.6f,    1.5f,   0.65f}; // AGC - PI control, proportional gain parameter
const double agcControlKi[AGC_NUM_PRESETS]    = {    1.7f,   1.85f,    1.2f}; // AGC - PI control, integral gain parameter
const float agcSampleSmooth[AGC_NUM_PRESETS]  = {  1/12.f,   1/6.f,  1/16.f}; // smoothing factor for sampleAgc (use rawSampleAgc if you want the non-smoothed value)
// AGC presets end

static AudioSource *audioSource = nullptr;
static uint8_t useInputFilter = 0;                        // enables low-cut filtering. Applies before FFT.

//WLEDMM add experimental settings
static uint8_t micLevelMethod = 0;                        // 0=old "floating" miclev, 1=new  "freeze" mode, 2=fast freeze mode (mode 2 may not work for you)
#if defined(CONFIG_IDF_TARGET_ESP32S2) || defined(CONFIG_IDF_TARGET_ESP32C3)
static uint8_t averageByRMS = false;                      // false: use mean value, true: use RMS (root mean squared). use simpler method on slower MCUs.
#else
static uint8_t averageByRMS = true;                       // false: use mean value, true: use RMS (root mean squared). use better method on fast MCUs.
#endif
static uint8_t freqDist = 0;                              // 0=old 1=rightshift mode


// variables used in effects
//static int16_t  volumeRaw = 0;       // either sampleRaw or rawSampleAgc depending on soundAgc
//static float my_magnitude =0.0f;     // FFT_Magnitude, scaled by multAgc

// shared vars for debugging
#ifdef MIC_LOGGER
static volatile float    micReal_min = 0.0f;             // MicIn data min from last batch of samples
static volatile float    micReal_avg = 0.0f;             // MicIn data average (from last batch of samples)
static volatile float    micReal_max = 0.0f;             // MicIn data max from last batch of samples
#if 0
static volatile float    micReal_min2 = 0.0f;             // MicIn data min after filtering
static volatile float    micReal_max2 = 0.0f;             // MicIn data max after filtering
#endif
#endif

////////////////////
// Begin FFT Code //
////////////////////

// some prototypes, to ensure consistent interfaces
static float mapf(float x, float in_min, float in_max, float out_min, float out_max); // map function for float
static float fftAddAvg(int from, int to);   // average of several FFT result bins
void FFTcode(void * parameter);      // audio processing task: read samples, run FFT, fill GEQ channels from FFT results
static void runMicFilter(uint16_t numSamples, float *sampleBuffer);          // pre-filtering of raw samples (band-pass)
static void postProcessFFTResults(bool noiseGateOpen, int numberOfChannels); // post-processing and post-amp of GEQ channels


static TaskHandle_t FFT_Task = nullptr;

// Table of multiplication factors so that we can even out the frequency response.
#define MAX_PINK 10  // 0 = standard, 1= line-in (pink noise only), 2..4 = IMNP441, 5..6 = ICS-43434, ,7=SPM1423, 8..9 = userdef, 10= flat (no pink noise adjustment)
static const float fftResultPink[MAX_PINK+1][NUM_GEQ_CHANNELS] = { 
          { 1.70f, 1.71f, 1.73f, 1.78f, 1.68f, 1.56f, 1.55f, 1.63f, 1.79f, 1.62f, 1.80f, 2.06f, 2.47f, 3.35f, 6.83f, 9.55f },  //  0 default from SR WLED
      //  { 1.30f, 1.32f, 1.40f, 1.46f, 1.52f, 1.57f, 1.68f, 1.80f, 1.89f, 2.00f, 2.11f, 2.21f, 2.30f, 2.39f, 3.09f, 4.34f },  //  - Line-In Generic -> pink noise adjustment only
          { 2.35f, 1.32f, 1.32f, 1.40f, 1.48f, 1.57f, 1.68f, 1.80f, 1.89f, 1.95f, 2.14f, 2.26f, 2.50f, 2.90f, 4.20f, 6.50f },  //  1 Line-In CS5343 + DC blocker

          { 1.82f, 1.72f, 1.70f, 1.50f, 1.52f, 1.57f, 1.68f, 1.80f, 1.89f, 2.00f, 2.11f, 2.21f, 2.30f, 2.90f, 3.86f, 6.29f},   //  2 IMNP441 datasheet response profile * pink noise
          { 2.80f, 2.20f, 1.30f, 1.15f, 1.55f, 2.45f, 4.20f, 2.80f, 3.20f, 3.60f, 4.20f, 4.90f, 5.70f, 6.05f,10.50f,14.85f},   //  3 IMNP441 - big speaker, strong bass
          // next one has not much visual differece compared to default IMNP441 profile
          { 12.0f, 6.60f, 2.60f, 1.15f, 1.35f, 2.05f, 2.85f, 2.50f, 2.85f, 3.30f, 2.25f, 4.35f, 3.80f, 3.75f, 6.50f, 9.00f},   //  4 IMNP441 - voice, or small speaker

          { 2.75f, 1.60f, 1.40f, 1.46f, 1.52f, 1.57f, 1.68f, 1.80f, 1.89f, 2.00f, 2.11f, 2.21f, 2.30f, 1.75f, 2.55f, 3.60f },  //  5 ICS-43434 datasheet response * pink noise
          { 2.90f, 1.25f, 0.75f, 1.08f, 2.35f, 3.55f, 3.60f, 3.40f, 2.75f, 3.45f, 4.40f, 6.35f, 6.80f, 6.80f, 8.50f,10.64f },  //  6 ICS-43434 - big speaker, strong bass

          { 1.65f, 1.00f, 1.05f, 1.30f, 1.48f, 1.30f, 1.80f, 3.00f, 1.50f, 1.65f, 2.56f, 3.00f, 2.60f, 2.30f, 5.00f, 3.00f },  //  7 SPM1423
          { 2.25f, 1.60f, 1.30f, 1.60f, 2.20f, 3.20f, 3.06f, 2.60f, 2.85f, 3.50f, 4.10f, 4.80f, 5.70f, 6.05f,10.50f,14.85f },  //  8 userdef #1 for ewowi (enhance median/high freqs)
          { 4.75f, 3.60f, 2.40f, 2.46f, 3.52f, 1.60f, 1.68f, 3.20f, 2.20f, 2.00f, 2.30f, 2.41f, 2.30f, 1.25f, 4.55f, 6.50f },  //  9 userdef #2 for softhack (mic hidden inside mini-shield)

          { 2.38f, 2.18f, 2.07f, 1.70f, 1.70f, 1.70f, 1.70f, 1.70f, 1.70f, 1.70f, 1.70f, 1.70f, 1.95f, 1.70f, 2.13f, 2.47f }   // 10 almost FLAT (IMNP441 but no PINK noise adjustments)
};

  /* how to make your own profile:
  * ===============================
   * preparation: make sure your microphone has direct line-of-sigh with the speaker, 1-2meter distance is best
   * Prepare your HiFi equipment: disable all "Sound enhancements" - like Loudness, Equalizer, Bass Boost. Bass/Treble controls set to middle.
   * Your HiFi equipment should receive its audio input from Line-In, SPDIF, HDMI, or another "undistorted" connection (like CDROM). 
   * Try not to use Bluetooth or MP3 when playing the "pink noise" audio. BT-audio and MP3 both perform "acoustic adjustments" that we don't want now.

   * SR WLED: enable AGC ("standard" or "lazy"), set squelch to a low level, check that LEDs don't reacts in silence.
   * SR WLED: select "Generic Line-In" as your Frequency Profile, "Linear" or "Square Root" as Frequency Scale
   * SR WLED: Dynamic Limiter On, Dynamics Fall Time around 4200 - makes GEQ hold peaks for much longer
   * SR WLED: Select GEQ effect, move all effect slider to max (i.e. right side)

   * Measure: play Pink Noise for 2-3 minutes - for examples from youtube https://www.youtube.com/watch?v=ZXtimhT-ff4
   * Measure: Take a Photo. Make sure that LEDs for each "bar" are well visible (ou need to count them later)

   * Your own profile: 
   *  - Target for each LED bar is 50% to 75% of the max height --> 8(high) x 16(wide) panel means target = 5. 32 x 16 means target = 22.
   *  - From left to right - count the LEDs in each of the 16 frequency columns (that's why you need the photo). This is the barheight for each channel.
   *  - math time! Find the multiplier that will bring each bar to to target.
   *    * in case of square root scale: multiplier = (target * target) / (barheight * barheight)
   *    * in case of linear scale:      multiplier = target / barheight
   * 
   *  - replace one of the "userdef" lines with a copy of the parameter line for "Line-In", 
   *  - go through your new "userdef" parameter line, multiply each entry with the mutliplier you found for that column.

   * Compile + upload
   * Test your new profile (same procedure as above). Iterate the process to improve results.
   */

// globals and FFT Output variables shared with animations
static float FFT_MajPeakSmth = 1.0f;            // FFT: (peak) frequency, smooth
#if defined(WLED_DEBUG) || defined(SR_DEBUG) || defined(SR_STATS)
static float fftTaskCycle = 0;      // avg cycle time for FFT task
static float fftTime = 0;           // avg time for single FFT
static float sampleTime = 0;        // avg (blocked) time for reading I2S samples
#endif

// FFT Task variables (filtering and post-processing)
static float   lastFftCalc[NUM_GEQ_CHANNELS] = {0.0f};                // backup of last FFT channels (before postprocessing)

#if !defined(CONFIG_IDF_TARGET_ESP32C3)
// audio source parameters and constant
constexpr SRate_t SAMPLE_RATE = 96000;        // Base sample rate in Hz - 22Khz is a standard rate. Physical sample time -> 23ms
//constexpr SRate_t SAMPLE_RATE = 16000;        // 16kHz - use if FFTtask takes more than 20ms. Physical sample time -> 32ms
//constexpr SRate_t SAMPLE_RATE = 20480;        // Base sample rate in Hz - 20Khz is experimental.    Physical sample time -> 25ms
//constexpr SRate_t SAMPLE_RATE = 10240;        // Base sample rate in Hz - previous default.         Physical sample time -> 50ms
#ifndef WLEDMM_FASTPATH
#define FFT_MIN_CYCLE 21                      // minimum time before FFT task is repeated. Use with 22Khz sampling
#else
#define FFT_MIN_CYCLE 15                      // reduce min time, to allow faster catch-up when I2S is lagging 
#endif
//#define FFT_MIN_CYCLE 30                      // Use with 16Khz sampling
//#define FFT_MIN_CYCLE 23                      // minimum time before FFT task is repeated. Use with 20Khz sampling
//#define FFT_MIN_CYCLE 46                      // minimum time before FFT task is repeated. Use with 10Khz sampling
#else
// slightly lower the sampling rate for -C3, to improve stability
//constexpr SRate_t SAMPLE_RATE = 20480;        // 20Khz; Physical sample time -> 25ms
//#define FFT_MIN_CYCLE 23                      // minimum time before FFT task is repeated.
constexpr SRate_t SAMPLE_RATE = 18000;          // 18Khz; Physical sample time -> 28ms
#define FFT_MIN_CYCLE 25                        // minimum time before FFT task is repeated.
// try 16Khz in case your device still lags and responds too slowly.
//constexpr SRate_t SAMPLE_RATE = 16000;        // 16Khz -> Physical sample time -> 32ms
//#define FFT_MIN_CYCLE 30                      // minimum time before FFT task is repeated.
#endif

// FFT Constants
constexpr uint16_t samplesFFT = 512;            // Samples in an FFT batch - This value MUST ALWAYS be a power of 2
constexpr uint16_t samplesFFT_2 = 256;          // meaningfull part of FFT results - only the "lower half" contains useful information.
// the following are observed values, supported by a bit of "educated guessing"
//#define FFT_DOWNSCALE 0.65f                             // 20kHz - downscaling factor for FFT results - "Flat-Top" window @20Khz, old freq channels 
//#define FFT_DOWNSCALE 0.46f                             // downscaling factor for FFT results - for "Flat-Top" window @22Khz, new freq channels
#define FFT_DOWNSCALE 0.40f                             // downscaling factor for FFT results, RMS averaging
#define LOG_256  5.54517744f                            // log(256)

// These are the input and output vectors.  Input vectors receive computed results from FFT.
static float vReal[samplesFFT] = {0.0f};       // FFT sample inputs / freq output -  these are our raw result bins
static float vImag[samplesFFT] = {0.0f};       // imaginary parts

#ifdef FFT_MAJORPEAK_HUMAN_EAR
static float pinkFactors[samplesFFT] = {0.0f};              // "pink noise" correction factors
constexpr float pinkcenter = 23.66;                         // sqrt(560) - center freq for scaling is 560 hz. 
constexpr float binWidth = SAMPLE_RATE / (float)samplesFFT; // frequency range of each FFT result bin
#endif


// Create FFT object
#ifdef UM_AUDIOREACTIVE_USE_NEW_FFT
// lib_deps += https://github.com/kosme/arduinoFFT#develop @ 1.9.2
#if  !defined(CONFIG_IDF_TARGET_ESP32S2) && !defined(CONFIG_IDF_TARGET_ESP32C3)
// these options actually cause slow-down on -S2 (-S2 doesn't have floating point hardware)
//#define FFT_SPEED_OVER_PRECISION     // enables use of reciprocals (1/x etc), and an a few other speedups - WLEDMM not faster on ESP32
//#define FFT_SQRT_APPROXIMATION       // enables "quake3" style inverse sqrt                               - WLEDMM slower on ESP32
#endif
#define sqrt(x) sqrtf(x)             // little hack that reduces FFT time by 10-50% on ESP32 (as alternative to FFT_SQRT_APPROXIMATION)
#define sqrt_internal sqrtf          // see https://github.com/kosme/arduinoFFT/pull/83
#else
  // around 50% slower on -S2
// lib_deps += https://github.com/blazoncek/arduinoFFT.git
#endif
#include <arduinoFFT.h>

#ifdef UM_AUDIOREACTIVE_USE_NEW_FFT
#if defined(FFT_LIB_REV) && FFT_LIB_REV > 0x19
  // arduinoFFT 2.x has a slightly different API
  static ArduinoFFT<float> FFT = ArduinoFFT<float>( vReal, vImag, samplesFFT, SAMPLE_RATE, true);
#else
  // recommended version optimized by @softhack007 (API version 1.9)
  static float windowWeighingFactors[samplesFFT] = {0.0f}; // cache for FFT windowing factors
  static ArduinoFFT<float> FFT = ArduinoFFT<float>( vReal, vImag, samplesFFT, SAMPLE_RATE, windowWeighingFactors);
#endif
#else
static arduinoFFT FFT = arduinoFFT(vReal, vImag, samplesFFT, SAMPLE_RATE);
#endif

// Helper functions

// float version of map()
static float mapf(float x, float in_min, float in_max, float out_min, float out_max){
  return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
}

// compute average of several FFT result bins
// linear average
static float fftAddAvgLin(int from, int to) {
  float result = 0.0f;
  for (int i = from; i <= to; i++) {
    result += vReal[i];
  }
  return result / float(to - from + 1);
}
// RMS average
static float fftAddAvgRMS(int from, int to) {
  double result = 0.0;
  for (int i = from; i <= to; i++) {
    result += vReal[i] * vReal[i];
  }
  return sqrtf(result / float(to - from + 1));
}

static float fftAddAvg(int from, int to) {
  if (from == to) return vReal[from];              // small optimization
  if (averageByRMS) return fftAddAvgRMS(from, to); // use SMS
  else return fftAddAvgLin(from, to);              // use linear average
}

#if defined(CONFIG_IDF_TARGET_ESP32C3)
constexpr bool skipSecondFFT = true;
#else
constexpr bool skipSecondFFT = false;
#endif

// High-Pass "DC blocker" filter
// see https://www.dsprelated.com/freebooks/filters/DC_Blocker.html
static void runDCBlocker(uint_fast16_t numSamples, float *sampleBuffer) {
  constexpr float filterR = 0.990f;      // around 40hz
  static float xm1 = 0.0f;
  static SR_HIRES_TYPE ym1 = 0.0f;

  for (unsigned i=0; i < numSamples; i++) {
    float value = sampleBuffer[i];
    SR_HIRES_TYPE filtered = (SR_HIRES_TYPE)(value-xm1) + filterR*ym1;
    xm1 = value;
    ym1 = filtered;    
    sampleBuffer[i] = filtered;
  }  
}

//
// FFT main task
//
void FFTcode(void * parameter)
{
  #ifdef SR_DEBUG
    USER_FLUSH();
    USER_PRINT("AR: "); USER_PRINT(pcTaskGetTaskName(NULL));
    USER_PRINT(" task started on core "); USER_PRINT(xPortGetCoreID()); // causes trouble on -S2
    USER_PRINT(" [prio="); USER_PRINT(uxTaskPriorityGet(NULL));
    USER_PRINT(", min free stack="); USER_PRINT(uxTaskGetStackHighWaterMark(NULL));
    USER_PRINTLN("]"); USER_FLUSH();
  #endif

  // see https://www.freertos.org/vtaskdelayuntil.html
  const TickType_t xFrequency = FFT_MIN_CYCLE * portTICK_PERIOD_MS;  
  const TickType_t xFrequencyDouble = FFT_MIN_CYCLE * portTICK_PERIOD_MS * 2;  
  static bool isFirstRun = false;

  #ifdef FFT_MAJORPEAK_HUMAN_EAR
  // pre-compute pink noise scaling table
  for(uint_fast16_t binInd = 0; binInd < samplesFFT; binInd++) {
    float binFreq = binInd * binWidth + binWidth/2.0f;
    if (binFreq > (SAMPLE_RATE * 0.42f))
      binFreq = (SAMPLE_RATE * 0.42f) - 0.25 * (binFreq - (SAMPLE_RATE * 0.42f)); // suppress noise and aliasing 
    pinkFactors[binInd] = sqrtf(binFreq) / pinkcenter;
  }
  pinkFactors[0] *= 0.5;  // suppress 0-42hz bin
  #endif

  TickType_t xLastWakeTime = xTaskGetTickCount();
  for(;;) {
    delay(1);           // DO NOT DELETE THIS LINE! It is needed to give the IDLE(0) task enough time and to keep the watchdog happy.
                        // taskYIELD(), yield(), vTaskDelay() and esp_task_wdt_feed() didn't seem to work.

    // Don't run FFT computing code if we're in Receive mode or in realtime mode
    if (disableSoundProcessing || (audioSyncEnabled == AUDIOSYNC_REC)) {
      isFirstRun = false;
      vTaskDelayUntil( &xLastWakeTime, xFrequency);        // release CPU, and let I2S fill its buffers
      continue;
    }

#if defined(WLED_DEBUG) || defined(SR_DEBUG)|| defined(SR_STATS)
    // timing
    uint64_t start = esp_timer_get_time();
    bool haveDoneFFT = false; // indicates if second measurement (FFT time) is valid
    static uint64_t lastCycleStart = 0;
    static uint64_t lastLastTime = 0;
    if ((lastCycleStart > 0) && (lastCycleStart < start)) { // filter out overflows
      uint64_t taskTimeInMillis = ((start - lastCycleStart) +5ULL) / 10ULL; // "+5" to ensure proper rounding
      fftTaskCycle = (((taskTimeInMillis + lastLastTime)/2) *4 + fftTaskCycle*6)/10.0; // smart smooth
      lastLastTime = taskTimeInMillis;
    }
    lastCycleStart = start;
#endif

    // get a fresh batch of samples from I2S
    if (audioSource) audioSource->getSamples(vReal, samplesFFT);

#if defined(WLED_DEBUG) || defined(SR_DEBUG)|| defined(SR_STATS)
    // debug info in case that stack usage changes
    static unsigned int minStackFree = UINT32_MAX;
    unsigned int stackFree = uxTaskGetStackHighWaterMark(NULL);
    if (minStackFree > stackFree) {
      minStackFree = stackFree;
      DEBUGSR_PRINTF("|| %-9s min free stack %d\n", pcTaskGetTaskName(NULL), minStackFree); //WLEDMM
    }
    // timing
    if (start < esp_timer_get_time()) { // filter out overflows
      uint64_t sampleTimeInMillis = (esp_timer_get_time() - start +5ULL) / 10ULL; // "+5" to ensure proper rounding
      sampleTime = (sampleTimeInMillis*3 + sampleTime*7)/10.0; // smooth
    }
    start = esp_timer_get_time(); // start measuring FFT time
#endif

    xLastWakeTime = xTaskGetTickCount();       // update "last unblocked time" for vTaskDelay
    isFirstRun = !isFirstRun; //  toggle throttle

#ifdef MIC_LOGGER
    float datMin = 0.0f;
    float datMax = 0.0f;
    double datAvg = 0.0f;
    for (int i=0; i < samplesFFT; i++) {
      if (i==0) {
        datMin = datMax = vReal[i];
      } else {
        if (datMin >  vReal[i]) datMin =  vReal[i];
        if (datMax <  vReal[i]) datMax =  vReal[i];
      }
      datAvg +=  vReal[i];
    }
#endif

#if defined(WLEDMM_FASTPATH) && !defined(CONFIG_IDF_TARGET_ESP32S2) && !defined(CONFIG_IDF_TARGET_ESP32C3) && defined(ARDUINO_ARCH_ESP32)
    // experimental - be nice to LED update task (trying to avoid flickering) - dual core only
    if (strip.isServicing()) delay(2);
#endif

    // band pass filter - can reduce noise floor by a factor of 50
    // downside: frequencies below 100Hz will be ignored
   if ((useInputFilter > 0) && (useInputFilter < 99)) {
      switch(useInputFilter) {
        case 1: runMicFilter(samplesFFT, vReal); break;                   // PDM microphone bandpass
        case 2: runDCBlocker(samplesFFT, vReal); break;                   // generic Low-Cut + DC blocker (~40hz cut-off)
      }
    }

    // set imaginary parts to 0
    memset(vImag, 0, sizeof(vImag));

    // find highest sample in the batch, and count zero crossings
    float maxSample = 0.0f;                         // max sample from FFT batch
    uint_fast16_t newZeroCrossingCount = 0;
    for (int i=0; i < samplesFFT; i++) {
	    // pick our  our current mic sample - we take the max value from all samples that go into FFT
	    if ((vReal[i] <= (INT16_MAX - 1024)) && (vReal[i] >= (INT16_MIN + 1024)))  //skip extreme values - normally these are artefacts
        if (fabsf((float)vReal[i]) > maxSample) maxSample = fabsf((float)vReal[i]);

      // WLED-MM/TroyHacks: Calculate zero crossings
      //
      if (i < (samplesFFT-1)) {
        if (__builtin_signbit(vReal[i]) != __builtin_signbit(vReal[i+1]))  // test sign bit: sign changed -> zero crossing
            newZeroCrossingCount++;
      }
    }
    newZeroCrossingCount = (newZeroCrossingCount*2)/3; // reduce value so it typically stays below 256
    zeroCrossingCount = newZeroCrossingCount; // update only once, to avoid that effects pick up an intermediate value

    // release highest sample to volume reactive effects early - not strictly necessary here - could also be done at the end of the function
    // early release allows the filters (getSample() and agcAvg()) to work with fresh values - we will have matching gain and noise gate values when we want to process the FFT results.
    micDataReal = maxSample;
#ifdef MIC_LOGGER
    micReal_min = datMin;
    micReal_max = datMax;
    micReal_avg = datAvg / samplesFFT;
#if 0
    // compute mix/max again after filering - usefull for filter debugging
    for (int i=0; i < samplesFFT; i++) {
      if (i==0) {
        datMin = datMax = vReal[i];
      } else {
        if (datMin >  vReal[i]) datMin =  vReal[i];
        if (datMax <  vReal[i]) datMax =  vReal[i];
      }
    }
    micReal_min2 = datMin;
    micReal_max2 = datMax;
#endif
#endif
    // run FFT (takes 3-5ms on ESP32)
    //if (fabsf(sampleAvg) > 0.25f) { // noise gate open
    if (fabsf(volumeSmth) > 0.25f) { // noise gate open
      if ((skipSecondFFT == false) || (isFirstRun == true)) {
        // run FFT (takes 2-3ms on ESP32, ~12ms on ESP32-S2, ~30ms on -C3)
        #ifdef UM_AUDIOREACTIVE_USE_NEW_FFT
        FFT.dcRemoval();                                            // remove DC offset
        #if !defined(FFT_PREFER_EXACT_PEAKS)
          FFT.windowing( FFTWindow::Flat_top, FFTDirection::Forward);        // Weigh data using "Flat Top" function - better amplitude accuracy
        #else
          FFT.windowing(FFTWindow::Blackman_Harris, FFTDirection::Forward);  // Weigh data using "Blackman- Harris" window - sharp peaks due to excellent sideband rejection
        #endif
        FFT.compute( FFTDirection::Forward );                       // Compute FFT
        FFT.complexToMagnitude();                                   // Compute magnitudes
        vReal[0] = 0;   // The remaining DC offset on the signal produces a strong spike on position 0 that should be eliminated to avoid issues.
        #else
        FFT.DCRemoval(); // let FFT lib remove DC component, so we don't need to care about this in getSamples()

        //FFT.Windowing( FFT_WIN_TYP_HAMMING, FFT_FORWARD );        // Weigh data - standard Hamming window
        //FFT.Windowing( FFT_WIN_TYP_BLACKMAN, FFT_FORWARD );       // Blackman window - better side freq rejection
        #if !defined(FFT_PREFER_EXACT_PEAKS)
          FFT.Windowing( FFT_WIN_TYP_FLT_TOP, FFT_FORWARD );        // Flat Top Window - better amplitude accuracy
        #else
          FFT.Windowing( FFT_WIN_TYP_BLACKMAN_HARRIS, FFT_FORWARD );// Blackman-Harris - excellent sideband rejection
        #endif
        FFT.Compute( FFT_FORWARD );                             // Compute FFT
        FFT.ComplexToMagnitude();                               // Compute magnitudes
        #endif

        float last_majorpeak = FFT_MajorPeak;
        float last_magnitude = FFT_Magnitude;

        #ifdef FFT_MAJORPEAK_HUMAN_EAR
        // scale FFT results
        for(uint_fast16_t binInd = 0; binInd < samplesFFT; binInd++)
          vReal[binInd] *= pinkFactors[binInd];
        #endif

        #ifdef UM_AUDIOREACTIVE_USE_NEW_FFT
        #if defined(FFT_LIB_REV) && FFT_LIB_REV > 0x19
          // arduinoFFT 2.x has a slightly different API
          FFT.majorPeak(&FFT_MajorPeak, &FFT_Magnitude);
        #else
          FFT.majorPeak(FFT_MajorPeak, FFT_Magnitude);                // let the effects know which freq was most dominant
        #endif
        #else
          FFT.MajorPeak(&FFT_MajorPeak, &FFT_Magnitude);
        #endif

        if (FFT_MajorPeak < (SAMPLE_RATE /  samplesFFT)) {FFT_MajorPeak = 1.0f; FFT_Magnitude = 0;}                  // too low - use zero
        if (FFT_MajorPeak > (0.42f * SAMPLE_RATE)) {FFT_MajorPeak = last_majorpeak; FFT_Magnitude = last_magnitude;} // too high - keep last peak

        #ifdef FFT_MAJORPEAK_HUMAN_EAR
        // undo scaling - we want unmodified values for FFTResult[] computations
        for(uint_fast16_t binInd = 0; binInd < samplesFFT; binInd++)
          vReal[binInd] *= 1.0f/pinkFactors[binInd];
        //fix peak magnitude
        if ((FFT_MajorPeak > (binWidth/1.25f)) && (FFT_MajorPeak < (SAMPLE_RATE/2.2f)) && (FFT_Magnitude > 4.0f)) {
          unsigned peakBin = constrain((int)((FFT_MajorPeak + binWidth/2.0f) / binWidth), 0, samplesFFT -1);
          FFT_Magnitude *= fmaxf(1.0f/pinkFactors[peakBin], 1.0f);
        }
        #endif
        FFT_MajorPeak = constrain(FFT_MajorPeak, 1.0f, 11025.0f);   // restrict value to range expected by effects
        FFT_MajPeakSmth = FFT_MajPeakSmth + 0.42 * (FFT_MajorPeak - FFT_MajPeakSmth);   // I like this "swooping peak" look

      } else { // skip second run --> clear fft results, keep peaks
        memset(vReal, 0, sizeof(vReal)); 
      }
#if defined(WLED_DEBUG) || defined(SR_DEBUG) || defined(SR_STATS)
      haveDoneFFT = true;
#endif

    } else { // noise gate closed - only clear results as FFT was skipped. MIC samples are still valid when we do this.
      memset(vReal, 0, sizeof(vReal));
      FFT_MajorPeak = 1;
      FFT_Magnitude = 0.001;
    }

    if ((skipSecondFFT == false) || (isFirstRun == true)) {

      for (int i = 0; i < samplesFFT; i++) {
        float t = fabsf(vReal[i]);                      // just to be sure - values in fft bins should be positive any way
        vReal[i] = t / 16.0f;                           // Reduce magnitude. Want end result to be scaled linear and ~4096 max.
      } // for()

      // mapping of FFT result bins to frequency channels
      //if (fabsf(sampleAvg) > 0.25f) { // noise gate open
      if (fabsf(volumeSmth) > 0.25f) { // noise gate open
#if 0
    /* This FFT post processing is a DIY endeavour. What we really need is someone with sound engineering expertise to do a great job here AND most importantly, that the animations look GREAT as a result.
    *
    * Andrew's updated mapping of 256 bins down to the 16 result bins with Sample Freq = 10240, samplesFFT = 512 and some overlap.
    * Based on testing, the lowest/Start frequency is 60 Hz (with bin 3) and a highest/End frequency of 5120 Hz in bin 255.
    * Now, Take the 60Hz and multiply by 1.320367784 to get the next frequency and so on until the end. Then determine the bins.
    * End frequency = Start frequency * multiplier ^ 16
    * Multiplier = (End frequency/ Start frequency) ^ 1/16
    * Multiplier = 1.320367784
    */                                    //  Range
      fftCalc[ 0] = fftAddAvg(2,4);       // 60 - 100
      fftCalc[ 1] = fftAddAvg(4,5);       // 80 - 120
      fftCalc[ 2] = fftAddAvg(5,7);       // 100 - 160
      fftCalc[ 3] = fftAddAvg(7,9);       // 140 - 200
      fftCalc[ 4] = fftAddAvg(9,12);      // 180 - 260
      fftCalc[ 5] = fftAddAvg(12,16);     // 240 - 340
      fftCalc[ 6] = fftAddAvg(16,21);     // 320 - 440
      fftCalc[ 7] = fftAddAvg(21,29);     // 420 - 600
      fftCalc[ 8] = fftAddAvg(29,37);     // 580 - 760
      fftCalc[ 9] = fftAddAvg(37,48);     // 740 - 980
      fftCalc[10] = fftAddAvg(48,64);     // 960 - 1300
      fftCalc[11] = fftAddAvg(64,84);     // 1280 - 1700
      fftCalc[12] = fftAddAvg(84,111);    // 1680 - 2240
      fftCalc[13] = fftAddAvg(111,147);   // 2220 - 2960
      fftCalc[14] = fftAddAvg(147,194);   // 2940 - 3900
      fftCalc[15] = fftAddAvg(194,250);   // 3880 - 5000 // avoid the last 5 bins, which are usually inaccurate
#else
  //WLEDMM: different distributions
  if (freqDist == 0) {
      /* new mapping, optimized for 22050 Hz by softhack007 --- update: removed overlap */
                                                    // bins frequency  range
      if (useInputFilter==1) {
        // skip frequencies below 100hz
        fftCalc[ 0] = 0.8f * fftAddAvg(3,3);
        fftCalc[ 1] = 0.9f * fftAddAvg(4,4);
        fftCalc[ 2] = fftAddAvg(5,5);
        fftCalc[ 3] = fftAddAvg(6,6);
        // don't use the last bins from 206 to 255. 
        fftCalc[15] = fftAddAvg(165,205) * 0.75f;   // 40 7106 - 8828 high             -- with some damping
      } else {
        fftCalc[ 0] = fftAddAvg(1,1);               // 1    43 - 86   sub-bass
        fftCalc[ 1] = fftAddAvg(2,2);               // 1    86 - 129  bass
        fftCalc[ 2] = fftAddAvg(3,4);               // 2   129 - 216  bass
        fftCalc[ 3] = fftAddAvg(5,6);               // 2   216 - 301  bass + midrange
        // don't use the last bins from 216 to 255. They are usually contaminated by aliasing (aka noise) 
        fftCalc[15] = fftAddAvg(165,215) * 0.70f;   // 50 7106 - 9259 high             -- with some damping
      }
      fftCalc[ 4] = fftAddAvg(7,9);                // 3   301 - 430  midrange
      fftCalc[ 5] = fftAddAvg(10,12);               // 3   430 - 560  midrange
      fftCalc[ 6] = fftAddAvg(13,18);               // 5   560 - 818  midrange
      fftCalc[ 7] = fftAddAvg(19,25);               // 7   818 - 1120 midrange -- 1Khz should always be the center !
      fftCalc[ 8] = fftAddAvg(26,32);               // 7  1120 - 1421 midrange
      fftCalc[ 9] = fftAddAvg(33,43);               // 9  1421 - 1895 midrange
      fftCalc[10] = fftAddAvg(44,55);               // 12 1895 - 2412 midrange + high mid
      fftCalc[11] = fftAddAvg(56,69);               // 14 2412 - 3015 high mid
      fftCalc[12] = fftAddAvg(70,85);               // 16 3015 - 3704 high mid
      fftCalc[13] = fftAddAvg(86,103);              // 18 3704 - 4479 high mid
      fftCalc[14] = fftAddAvg(104,164) * 0.88f;     // 61 4479 - 7106 high mid + high  -- with slight damping
  }
  else if (freqDist == 1) { //WLEDMM: Rightshift: note ewowi: frequencies in comments are not correct
      if (useInputFilter==1) {
        // skip frequencies below 100hz
        fftCalc[ 0] = 0.8f * fftAddAvg(1,1);
        fftCalc[ 1] = 0.9f * fftAddAvg(2,2);
        fftCalc[ 2] = fftAddAvg(3,3);
        fftCalc[ 3] = fftAddAvg(4,4);
        // don't use the last bins from 206 to 255. 
        fftCalc[15] = fftAddAvg(165,205) * 0.75f;   // 40 7106 - 8828 high             -- with some damping
      } else {
        fftCalc[ 0] = fftAddAvg(1,1);               // 1    43 - 86   sub-bass
        fftCalc[ 1] = fftAddAvg(2,2);               // 1    86 - 129  bass
        fftCalc[ 2] = fftAddAvg(3,3);               // 2   129 - 216  bass
        fftCalc[ 3] = fftAddAvg(4,4);               // 2   216 - 301  bass + midrange
        // don't use the last bins from 216 to 255. They are usually contaminated by aliasing (aka noise) 
        fftCalc[15] = fftAddAvg(165,215) * 0.70f;   // 50 7106 - 9259 high             -- with some damping
      }
      fftCalc[ 4] = fftAddAvg(5,6);                // 3   301 - 430  midrange
      fftCalc[ 5] = fftAddAvg(7,8);               // 3   430 - 560  midrange
      fftCalc[ 6] = fftAddAvg(9,10);               // 5   560 - 818  midrange
      fftCalc[ 7] = fftAddAvg(11,13);               // 7   818 - 1120 midrange -- 1Khz should always be the center !
      fftCalc[ 8] = fftAddAvg(14,18);               // 7  1120 - 1421 midrange
      fftCalc[ 9] = fftAddAvg(19,25);               // 9  1421 - 1895 midrange
      fftCalc[10] = fftAddAvg(26,36);               // 12 1895 - 2412 midrange + high mid
      fftCalc[11] = fftAddAvg(37,45);               // 14 2412 - 3015 high mid
      fftCalc[12] = fftAddAvg(46,66);               // 16 3015 - 3704 high mid
      fftCalc[13] = fftAddAvg(67,97);              // 18 3704 - 4479 high mid
      fftCalc[14] = fftAddAvg(98,164) * 0.88f;     // 61 4479 - 7106 high mid + high  -- with slight damping
  }
#endif
      } else {  // noise gate closed - just decay old values
        isFirstRun = false;
        for (int i=0; i < NUM_GEQ_CHANNELS; i++) {
          fftCalc[i] *= 0.85f;  // decay to zero
          if (fftCalc[i] < 4.0f) fftCalc[i] = 0.0f;
        }
      }

      memcpy(lastFftCalc, fftCalc, sizeof(lastFftCalc)); // make a backup of last "good" channels

    } else { // if second run skipped
      memcpy(fftCalc, lastFftCalc, sizeof(fftCalc)); // restore last "good" channels
    }

    // post-processing of frequency channels (pink noise adjustment, AGC, smoothing, scaling)
    if (pinkIndex > MAX_PINK) pinkIndex = MAX_PINK;
    //postProcessFFTResults((fabsf(sampleAvg) > 0.25f)? true : false , NUM_GEQ_CHANNELS);
    postProcessFFTResults((fabsf(volumeSmth)>0.25f)? true : false , NUM_GEQ_CHANNELS);    // this function modifies fftCalc, fftAvg and fftResult

#if defined(WLED_DEBUG) || defined(SR_DEBUG)|| defined(SR_STATS)
    // timing
    static uint64_t lastLastFFT = 0;
    if (haveDoneFFT && (start < esp_timer_get_time())) { // filter out overflows
      uint64_t fftTimeInMillis = ((esp_timer_get_time() - start) +5ULL) / 10ULL; // "+5" to ensure proper rounding
      fftTime  = (((fftTimeInMillis + lastLastFFT)/2) *3 + fftTime*7)/10.0; // smart smooth
      lastLastFFT = fftTimeInMillis;
    }
#endif

    // run peak detection
    autoResetPeak();
    detectSamplePeak();

    haveNewFFTResult = true;
    
    #if !defined(I2S_GRAB_ADC1_COMPLETELY)    
    if ((audioSource == nullptr) || (audioSource->getType() != AudioSource::Type_I2SAdc))  // the "delay trick" does not help for analog ADC
    #endif
    {
      if ((skipSecondFFT == false) || (fabsf(volumeSmth) < 0.25f)) {
        vTaskDelayUntil( &xLastWakeTime, xFrequency);        // release CPU, and let I2S fill its buffers
      } else if (isFirstRun == true) {
        vTaskDelayUntil( &xLastWakeTime, xFrequencyDouble);  // release CPU after performing FFT in "skip second run" mode
      }
    }
  } // for(;;)ever
} // FFTcode() task end


///////////////////////////
// Pre / Postprocessing  //
///////////////////////////

static void runMicFilter(uint16_t numSamples, float *sampleBuffer)          // pre-filtering of raw samples (band-pass)
{
  // low frequency cutoff parameter - see https://dsp.stackexchange.com/questions/40462/exponential-moving-average-cut-off-frequency
  //constexpr float alpha = 0.04f;   // 150Hz
  //constexpr float alpha = 0.03f;   // 110Hz
  constexpr float alpha = 0.0225f; // 80hz
  //constexpr float alpha = 0.01693f;// 60hz
  // high frequency cutoff  parameter
  //constexpr float beta1 = 0.75f;   // 11Khz
  //constexpr float beta1 = 0.82f;   // 15Khz
  //constexpr float beta1 = 0.8285f; // 18Khz
  constexpr float beta1 = 0.85f;  // 20Khz

  constexpr float beta2 = (1.0f - beta1) / 2.0;
  static float last_vals[2] = { 0.0f }; // FIR high freq cutoff filter
  static float lowfilt = 0.0f;          // IIR low frequency cutoff filter

  for (int i=0; i < numSamples; i++) {
        // FIR lowpass, to remove high frequency noise
        float highFilteredSample;
        if (i < (numSamples-1)) highFilteredSample = beta1*sampleBuffer[i] + beta2*last_vals[0] + beta2*sampleBuffer[i+1];  // smooth out spikes
        else highFilteredSample = beta1*sampleBuffer[i] + beta2*last_vals[0]  + beta2*last_vals[1];                  // special handling for last sample in array
        last_vals[1] = last_vals[0];
        last_vals[0] = sampleBuffer[i];
        sampleBuffer[i] = highFilteredSample;
        // IIR highpass, to remove low frequency noise
        lowfilt += alpha * (sampleBuffer[i] - lowfilt);
        sampleBuffer[i] = sampleBuffer[i] - lowfilt;
  }
}

static void postProcessFFTResults(bool noiseGateOpen, int numberOfChannels) // post-processing and post-amp of GEQ channels
{
    for (int i=0; i < numberOfChannels; i++) {

      if (noiseGateOpen) { // noise gate open
        // Adjustment for frequency curves.
        fftCalc[i] *= fftResultPink[pinkIndex][i];
        if (FFTScalingMode > 0) fftCalc[i] *= FFT_DOWNSCALE;  // adjustment related to FFT windowing function
        // Manual linear adjustment of gain using sampleGain adjustment for different input types.
        fftCalc[i] *= soundAgc ? multAgc : ((float)sampleGain/40.0f * (float)inputLevel/128.0f + 1.0f/16.0f); //apply gain, with inputLevel adjustment
        if(fftCalc[i] < 0) fftCalc[i] = 0;
      }

      // smooth results - rise fast, fall slower
      if(fftCalc[i] > fftAvg[i])   // rise fast 
        fftAvg[i] = fftCalc[i] *0.78f + 0.22f*fftAvg[i];  // will need approx 1-2 cycles (50ms) for converging against fftCalc[i]
      else {                       // fall slow
        if (decayTime < 250)      fftAvg[i] = fftCalc[i]*0.4f + 0.6f*fftAvg[i]; 
        else if (decayTime < 500)  fftAvg[i] = fftCalc[i]*0.33f + 0.67f*fftAvg[i]; 
        else if (decayTime < 1000) fftAvg[i] = fftCalc[i]*0.22f + 0.78f*fftAvg[i];  // approx  5 cycles (225ms) for falling to zero
        else if (decayTime < 2000) fftAvg[i] = fftCalc[i]*0.17f + 0.83f*fftAvg[i];  // default - approx  9 cycles (225ms) for falling to zero
        else if (decayTime < 3000) fftAvg[i] = fftCalc[i]*0.14f + 0.86f*fftAvg[i];  // approx 14 cycles (350ms) for falling to zero
        else if (decayTime < 4000) fftAvg[i] = fftCalc[i]*0.1f  + 0.9f*fftAvg[i];
        else fftAvg[i] = fftCalc[i]*0.05f  + 0.95f*fftAvg[i];
      }
      // constrain internal vars - just to be sure
      fftCalc[i] = constrain(fftCalc[i], 0.0f, 1023.0f);
      fftAvg[i] = constrain(fftAvg[i], 0.0f, 1023.0f);

      float currentResult;
      if(limiterOn == true)
        currentResult = fftAvg[i];
      else
        currentResult = fftCalc[i];

      switch (FFTScalingMode) {
        case 1:
            // Logarithmic scaling
            currentResult *= 0.42;                      // 42 is the answer ;-)
            currentResult -= 8.0;                       // this skips the lowest row, giving some room for peaks
            if (currentResult > 1.0) currentResult = logf(currentResult); // log to base "e", which is the fastest log() function
            else currentResult = 0.0;                   // special handling, because log(1) = 0; log(0) = undefined
            currentResult *= 0.85f + (float(i)/18.0f);  // extra up-scaling for high frequencies
            currentResult = mapf(currentResult, 0, LOG_256, 0, 255); // map [log(1) ... log(255)] to [0 ... 255]
        break;
        case 2:
            // Linear scaling
            currentResult *= 0.30f;                     // needs a bit more damping, get stay below 255
            currentResult -= 2.0;                       // giving a bit more room for peaks
            if (currentResult < 1.0f) currentResult = 0.0f;
            currentResult *= 0.85f + (float(i)/1.8f);   // extra up-scaling for high frequencies
        break;
        case 3:
            // square root scaling
            currentResult *= 0.38f;
            //currentResult *= 0.34f;                   //experiment
            currentResult -= 6.0f;
            if (currentResult > 1.0) currentResult = sqrtf(currentResult);
            else currentResult = 0.0;                   // special handling, because sqrt(0) = undefined
            currentResult *= 0.85f + (float(i)/4.5f);   // extra up-scaling for high frequencies
            //currentResult *= 0.80f + (float(i)/5.6f); //experiment
            currentResult = mapf(currentResult, 0.0, 16.0, 0.0, 255.0); // map [sqrt(1) ... sqrt(256)] to [0 ... 255]
        break;

        case 0:
        default:
            // no scaling - leave freq bins as-is
            currentResult -= 2; // just a bit more room for peaks
        break;
      }

      // Now, let's dump it all into fftResult. Need to do this, otherwise other routines might grab fftResult values prematurely.
      if (soundAgc > 0) {  // apply extra "GEQ Gain" if set by user
        float post_gain = (float)inputLevel/128.0f;
        if (post_gain < 1.0f) post_gain = ((post_gain -1.0f) * 0.8f) +1.0f;
        currentResult *= post_gain;
      }
      fftResult[i] = max(min((int)(currentResult+0.5f), 255), 0);  // +0.5 for proper rounding
    }
}
////////////////////
// Peak detection //
////////////////////

// peak detection is called from FFT task when vReal[] contains valid FFT results
static void detectSamplePeak(void) {
  bool havePeak = false;
#if 1
  // softhack007: this code continuously triggers while volume in the selected bin is above a certain threshold. So it does not detect peaks - it detects volume in a frequency bin.
  // Poor man's beat detection by seeing if sample > Average + some value.
  // This goes through ALL of the 255 bins - but ignores stupid settings
  // Then we got a peak, else we don't. The peak has to time out on its own in order to support UDP sound sync.
  if ((sampleAvg > 1) && (maxVol > 0) && (binNum > 4) && (vReal[binNum] > maxVol) && ((millis() - timeOfPeak) > 100)) {
    havePeak = true;
  }
#endif

#if 0
  // alternate detection, based on FFT_MajorPeak and FFT_Magnitude. Not much better...
  if ((binNum > 1)  && (maxVol > 8) && (binNum < 10) && (sampleAgc > 127) && 
      (FFT_MajorPeak > 50) && (FFT_MajorPeak < 250) && (FFT_Magnitude > (16.0f * (maxVol+42.0)) /*my_magnitude > 136.0f*16.0f*/) && 
      (millis() - timeOfPeak > 80)) {
    havePeak = true;
  }
#endif

  if (havePeak) {
    samplePeak    = true;
    timeOfPeak    = millis();
    udpSamplePeak = true;
  }
}

#endif

static void autoResetPeak(void) {
  uint16_t MinShowDelay = MAX(50, strip.getMinShowDelay());  // Fixes private class variable compiler error. Unsure if this is the correct way of fixing the root problem. -THATDONFC
  if (millis() - timeOfPeak > MinShowDelay) {          // Auto-reset of samplePeak after a complete frame has passed.
    samplePeak = false;
    if (audioSyncEnabled == AUDIOSYNC_NONE) udpSamplePeak = false;  // this is normally reset by transmitAudioData
  }
}

////////////////////
// usermod class  //
////////////////////

//class name. Use something descriptive and leave the ": public Usermod" part :)
class AudioReactive : public Usermod {

  private:
#ifdef ARDUINO_ARCH_ESP32

    #ifndef AUDIOPIN
    int8_t audioPin = -1;
    #else
    int8_t audioPin = AUDIOPIN;
    #endif
    #ifndef SR_DMTYPE // I2S mic type
    uint8_t dmType = 1; // 0=none/disabled/analog; 1=generic I2S
    #define SR_DMTYPE 1 // default type = I2S
    #else
    uint8_t dmType = SR_DMTYPE;
    #endif
    #ifndef I2S_SDPIN // aka DOUT
    int8_t i2ssdPin = 32;
    #else
    int8_t i2ssdPin = I2S_SDPIN;
    #endif
    #ifndef I2S_WSPIN // aka LRCL
    int8_t i2swsPin = 15;
    #else
    int8_t i2swsPin = I2S_WSPIN;
    #endif
    #ifndef I2S_CKPIN // aka BCLK
    int8_t i2sckPin = 14; /*PDM: set to I2S_PIN_NO_CHANGE*/
    #else
    int8_t i2sckPin = I2S_CKPIN;
    #endif
    #ifndef ES7243_SDAPIN
    int8_t sdaPin = -1;
    #else
    int8_t sdaPin = ES7243_SDAPIN;
    #endif
    #ifndef ES7243_SCLPIN
    int8_t sclPin = -1;
    #else
    int8_t sclPin = ES7243_SCLPIN;
    #endif
    #ifndef MCLK_PIN
    int8_t mclkPin = I2S_PIN_NO_CHANGE;  /* ESP32: only -1, 0, 1, 3 allowed*/
    #else
    int8_t mclkPin = MCLK_PIN;
    #endif
#endif
    // new "V2" audiosync struct - 44 Bytes
    struct __attribute__ ((packed)) audioSyncPacket {  // WLEDMM "packed" ensures that there are no additional gaps
      char    header[6];      //  06 Bytes  offset 0
      uint8_t gap1[2];        // gap added by compiler: 02 Bytes, offset 6
      float   sampleRaw;      //  04 Bytes  offset 8  - either "sampleRaw" or "rawSampleAgc" depending on soundAgc setting
      float   sampleSmth;     //  04 Bytes  offset 12 - either "sampleAvg" or "sampleAgc" depending on soundAgc setting
      uint8_t samplePeak;     //  01 Bytes  offset 16 - 0 no peak; >=1 peak detected. In future, this will also provide peak Magnitude
      uint8_t frameCounter;   //  01 Bytes  offset 17 - track duplicate/out of order packets
      uint8_t fftResult[16];  //  16 Bytes  offset 18
      uint16_t zeroCrossingCount; // 02 Bytes, offset 34
      float  FFT_Magnitude;   //  04 Bytes  offset 36
      float  FFT_MajorPeak;   //  04 Bytes  offset 40
    };

    // old "V1" audiosync struct - 83 Bytes payload, 88 bytes total - for backwards compatibility
    struct audioSyncPacket_v1 {
      char header[6];         //  06 Bytes
      uint8_t myVals[32];     //  32 Bytes
      int sampleAgc;          //  04 Bytes
      int sampleRaw;          //  04 Bytes
      float sampleAvg;        //  04 Bytes
      bool samplePeak;        //  01 Bytes
      uint8_t fftResult[16];  //  16 Bytes
      double FFT_Magnitude;   //  08 Bytes
      double FFT_MajorPeak;   //  08 Bytes
    };

    #define UDPSOUND_MAX_PACKET 96 // max packet size for audiosync, with a bit of "headroom"

    // set your config variables to their boot default value (this can also be done in readFromConfig() or a constructor if you prefer)
  #if defined(SR_ENABLE_DEFAULT) || defined(UM_AUDIOREACTIVE_ENABLE)
    bool     enabled = true;        // WLEDMM
  #else
    bool     enabled = false;
  #endif
    bool     initDone = false;

    // variables  for UDP sound sync
    WiFiUDP fftUdp;               // UDP object for sound sync (from WiFi UDP, not Async UDP!)
    unsigned long lastTime = 0;   // last time of running UDP Microphone Sync
#if defined(WLEDMM_FASTPATH)
    const uint16_t delayMs = 5;   // I don't want to sample too often and overload WLED
#else
    const uint16_t delayMs = 10;  // I don't want to sample too often and overload WLED
#endif
    uint16_t audioSyncPort= 11988;// default port for UDP sound sync

    bool updateIsRunning = false; // true during OTA.

#ifdef ARDUINO_ARCH_ESP32
    // used for AGC
    int      last_soundAgc = -1;   // used to detect AGC mode change (for resetting AGC internal error buffers)
    double   control_integrated = 0.0;   // persistent across calls to agcAvg(); "integrator control" = accumulated error

    // variables used by getSample() and agcAvg()
    int16_t  micIn = 0;           // Current sample starts with negative values and large values, which is why it's 16 bit signed
    double   sampleMax = 0.0;     // Max sample over a few seconds. Needed for AGC controller.
    double   micLev = 0.0;        // Used to convert returned value to have '0' as minimum. A leveller
    float    expAdjF = 0.0f;      // Used for exponential filter.
    float    sampleReal = 0.0f;	  // "sampleRaw" as float, to provide bits that are lost otherwise (before amplification by sampleGain or inputLevel). Needed for AGC.
    int16_t  sampleRaw = 0;       // Current sample. Must only be updated ONCE!!! (amplified mic value by sampleGain and inputLevel)
    int16_t  rawSampleAgc = 0;    // not smoothed AGC sample
#endif

    // variables used in effects
    int16_t  volumeRaw = 0;       // either sampleRaw or rawSampleAgc depending on soundAgc
    float my_magnitude =0.0f;     // FFT_Magnitude, scaled by multAgc
    float soundPressure = 0;      // Sound Pressure estimation, based on microphone raw readings. 0 ->5db, 255 ->105db

    // used to feed "Info" Page
    unsigned long last_UDPTime = 0;    // time of last valid UDP sound sync datapacket
    int receivedFormat = 0;            // last received UDP sound sync format - 0=none, 1=v1 (0.13.x), 2=v2 (0.14.x)
    float maxSample5sec = 0.0f;        // max sample (after AGC) in last 5 seconds 
    unsigned long sampleMaxTimer = 0;  // last time maxSample5sec was reset
    #define CYCLE_SAMPLEMAX 3500       // time window for merasuring

    // strings to reduce flash memory usage (used more than twice)
    static const char _name[];
    static const char _enabled[];
    static const char _inputLvl[];
#if defined(ARDUINO_ARCH_ESP32) && !defined(CONFIG_IDF_TARGET_ESP32S2) && !defined(CONFIG_IDF_TARGET_ESP32C3) && !defined(CONFIG_IDF_TARGET_ESP32S3)
    static const char _analogmic[];
#endif
    static const char _digitalmic[];
    static const char UDP_SYNC_HEADER[];
    static const char UDP_SYNC_HEADER_v1[];

    // private methods

    ////////////////////
    // Debug support  //
    ////////////////////
    void logAudio()
    {
      if (disableSoundProcessing && (!udpSyncConnected || ((audioSyncEnabled & AUDIOSYNC_REC) == 0))) return;   // no audio available
    #ifdef MIC_LOGGER
      // Debugging functions for audio input and sound processing. Comment out the values you want to see
      PLOT_PRINT("volumeSmth:");  PLOT_PRINT(volumeSmth + 256.0f);  PLOT_PRINT("\t");  // +256 to move above other lines
      //PLOT_PRINT("volumeRaw:");   PLOT_PRINT(volumeRaw + 256.0f); PLOT_PRINT("\t");  // +256 to move above other lines
      //PLOT_PRINT("samplePeak:");  PLOT_PRINT((samplePeak!=0) ? 128:0);   PLOT_PRINT("\t");
    #ifdef ARDUINO_ARCH_ESP32
      PLOT_PRINT("micMin:");     PLOT_PRINT(0.5f * micReal_min);    PLOT_PRINT("\t");  // scaled down to 50%, for better readability
      PLOT_PRINT("micMax:");     PLOT_PRINT(0.5f * micReal_max);    PLOT_PRINT("\t");  // scaled down to 50%
      //PLOT_PRINT("micAvg:");     PLOT_PRINT(0.5f * micReal_avg);  PLOT_PRINT("\t");  // scaled down to 50%
      //PLOT_PRINT("micDC:");      PLOT_PRINT(0.5f * (micReal_min + micReal_max)/2.0f);PLOT_PRINT("\t");  // scaled down to 50%
      PLOT_PRINT("micReal:");     PLOT_PRINT(micDataReal + 256.0f); PLOT_PRINT("\t");  // +256 to move above other lines
      PLOT_PRINT("DC_Level:");    PLOT_PRINT(micLev + 256.0f);      PLOT_PRINT("\t");  // +256 to move above other lines
      // //PLOT_PRINT("filtmicMin:");     PLOT_PRINT(0.5f * micReal_min2);  PLOT_PRINT("\t"); // scaled down to 50%
      // //PLOT_PRINT("filtmicMax:");     PLOT_PRINT(0.5f * micReal_max2);  PLOT_PRINT("\t"); // scaled down to 50%
      //PLOT_PRINT("sampleAgc:");   PLOT_PRINT(sampleAgc);   PLOT_PRINT("\t");
      //PLOT_PRINT("sampleAvg:");   PLOT_PRINT(sampleAvg);   PLOT_PRINT("\t");
      //PLOT_PRINT("sampleReal:");  PLOT_PRINT(sampleReal);  PLOT_PRINT("\t");
      //PLOT_PRINT("micIn:");       PLOT_PRINT(micIn);       PLOT_PRINT("\t");
      //PLOT_PRINT("sample:");      PLOT_PRINT(sample);      PLOT_PRINT("\t");
      //PLOT_PRINT("sampleMax:");   PLOT_PRINT(sampleMax);   PLOT_PRINT("\t");
      //PLOT_PRINT("multAgc:");     PLOT_PRINT(multAgc, 4);  PLOT_PRINT("\t");
    #endif
      PLOT_PRINTLN();
      PLOT_FLUSH();
    #endif

    #ifdef FFT_SAMPLING_LOG
      #if 0
        for(int i=0; i<NUM_GEQ_CHANNELS; i++) {
          PLOT_PRINT(fftResult[i]);
          PLOT_PRINT("\t");
        }
        PLOT_PRINTLN();
    #endif

      // OPTIONS are in the following format: Description \n Option
      //
      // Set true if wanting to see all the bands in their own vertical space on the Serial Plotter, false if wanting to see values in Serial Monitor
      const bool mapValuesToPlotterSpace = false;
      // Set true to apply an auto-gain like setting to to the data (this hasn't been tested recently)
      const bool scaleValuesFromCurrentMaxVal = false;
      // prints the max value seen in the current data
      const bool printMaxVal = false;
      // prints the min value seen in the current data
      const bool printMinVal = false;
      // if !scaleValuesFromCurrentMaxVal, we scale values from [0..defaultScalingFromHighValue] to [0..scalingToHighValue], lower this if you want to see smaller values easier
      const int defaultScalingFromHighValue = 256;
      // Print values to terminal in range of [0..scalingToHighValue] if !mapValuesToPlotterSpace, or [(i)*scalingToHighValue..(i+1)*scalingToHighValue] if mapValuesToPlotterSpace
      const int scalingToHighValue = 256;
      // set higher if using scaleValuesFromCurrentMaxVal and you want a small value that's also the current maxVal to look small on the plotter (can't be 0 to avoid divide by zero error)
      const int minimumMaxVal = 1;

      int maxVal = minimumMaxVal;
      int minVal = 0;
      for(int i = 0; i < NUM_GEQ_CHANNELS; i++) {
        if(fftResult[i] > maxVal) maxVal = fftResult[i];
        if(fftResult[i] < minVal) minVal = fftResult[i];
      }
      for(int i = 0; i < NUM_GEQ_CHANNELS; i++) {
        PLOT_PRINT(i); PLOT_PRINT(":");
        PLOT_PRINTF("%04ld ", map(fftResult[i], 0, (scaleValuesFromCurrentMaxVal ? maxVal : defaultScalingFromHighValue), (mapValuesToPlotterSpace*i*scalingToHighValue)+0, (mapValuesToPlotterSpace*i*scalingToHighValue)+scalingToHighValue-1));
      }
      if(printMaxVal) {
        PLOT_PRINTF("maxVal:%04d ", maxVal + (mapValuesToPlotterSpace ? 16*256 : 0));
      }
      if(printMinVal) {
        PLOT_PRINTF("%04d:minVal ", minVal);  // printed with value first, then label, so negative values can be seen in Serial Monitor but don't throw off y axis in Serial Plotter
      }
      if(mapValuesToPlotterSpace)
        PLOT_PRINTF("max:%04d ", (printMaxVal ? 17 : 16)*256); // print line above the maximum value we expect to see on the plotter to avoid autoscaling y axis
      else {
        PLOT_PRINTF("max:%04d ", 256);
      }
      PLOT_PRINTLN();
    #endif // FFT_SAMPLING_LOG
    } // logAudio()

#ifdef ARDUINO_ARCH_ESP32

    //////////////////////
    // Audio Processing //
    //////////////////////

    /*
    * A "PI controller" multiplier to automatically adjust sound sensitivity.
    * 
    * A few tricks are implemented so that sampleAgc does't only utilize 0% and 100%:
    * 0. don't amplify anything below squelch (but keep previous gain)
    * 1. gain input = maximum signal observed in the last 5-10 seconds
    * 2. we use two setpoints, one at ~60%, and one at ~80% of the maximum signal
    * 3. the amplification depends on signal level:
    *    a) normal zone - very slow adjustment
    *    b) emergency zone (<10% or >90%) - very fast adjustment
    */
    void agcAvg(unsigned long the_time)
    {
      const int AGC_preset = (soundAgc > 0)? (soundAgc-1): 0; // make sure the _compiler_ knows this value will not change while we are inside the function

      float lastMultAgc = multAgc;      // last multiplier used
      float multAgcTemp = multAgc;      // new multiplier
      float tmpAgc = sampleReal * multAgc;        // what-if amplified signal

      float control_error;                        // "control error" input for PI control

      if (last_soundAgc != soundAgc)
        control_integrated = 0.0;                // new preset - reset integrator

      // For PI controller, we need to have a constant "frequency"
      // so let's make sure that the control loop is not running at insane speed
      static unsigned long last_time = 0;
      unsigned long time_now = millis();
      if ((the_time > 0) && (the_time < time_now)) time_now = the_time;  // allow caller to override my clock

      if (time_now - last_time > 2)  {
        last_time = time_now;

        if((fabsf(sampleReal) < 2.0f) || (sampleMax < 1.0f)) {
          // MIC signal is "squelched" - deliver silence
          tmpAgc = 0;
          // we need to "spin down" the intgrated error buffer
          if (fabs(control_integrated) < 0.01)  control_integrated  = 0.0;
          else                                  control_integrated *= 0.91;
        } else {
          // compute new setpoint
          if (tmpAgc <= agcTarget0Up[AGC_preset])
            multAgcTemp = agcTarget0[AGC_preset] / sampleMax;   // Make the multiplier so that sampleMax * multiplier = first setpoint
          else
            multAgcTemp = agcTarget1[AGC_preset] / sampleMax;   // Make the multiplier so that sampleMax * multiplier = second setpoint
        }
        // limit amplification
        if (multAgcTemp > 32.0f)      multAgcTemp = 32.0f;
        if (multAgcTemp < 1.0f/64.0f) multAgcTemp = 1.0f/64.0f;

        // compute error terms
        control_error = multAgcTemp - lastMultAgc;
        
        if (((multAgcTemp > 0.085f) && (multAgcTemp < 6.5f))    //integrator anti-windup by clamping
            && (multAgc*sampleMax < agcZoneStop[AGC_preset]))   //integrator ceiling (>140% of max)
          control_integrated += control_error * 0.002 * 0.25;   // 2ms = integration time; 0.25 for damping
        else
          control_integrated *= 0.9;                            // spin down that integrator beast

        // apply PI Control 
        tmpAgc = sampleReal * lastMultAgc;                      // check "zone" of the signal using previous gain
        if ((tmpAgc > agcZoneHigh[AGC_preset]) || (tmpAgc < soundSquelch + agcZoneLow[AGC_preset])) {  // upper/lower emergency zone
          multAgcTemp = lastMultAgc + agcFollowFast[AGC_preset] * agcControlKp[AGC_preset] * control_error;
          multAgcTemp += agcFollowFast[AGC_preset] * agcControlKi[AGC_preset] * control_integrated;
        } else {                                                                         // "normal zone"
          multAgcTemp = lastMultAgc + agcFollowSlow[AGC_preset] * agcControlKp[AGC_preset] * control_error;
          multAgcTemp += agcFollowSlow[AGC_preset] * agcControlKi[AGC_preset] * control_integrated;
        }

        // limit amplification again - PI controller sometimes "overshoots"
        //multAgcTemp = constrain(multAgcTemp, 0.015625f, 32.0f); // 1/64 < multAgcTemp < 32
        if (multAgcTemp > 32.0f)      multAgcTemp = 32.0f;
        if (multAgcTemp < 1.0f/64.0f) multAgcTemp = 1.0f/64.0f;
      }

      // NOW finally amplify the signal
      tmpAgc = sampleReal * multAgcTemp;                  // apply gain to signal
      if (fabsf(sampleReal) < 2.0f) tmpAgc = 0.0f;        // apply squelch threshold
      //tmpAgc = constrain(tmpAgc, 0, 255);
      if (tmpAgc > 255) tmpAgc = 255.0f;                  // limit to 8bit
      if (tmpAgc < 1)   tmpAgc = 0.0f;                    // just to be sure

      // update global vars ONCE - multAgc, sampleAGC, rawSampleAgc
      multAgc = multAgcTemp;
      rawSampleAgc = 0.8f * tmpAgc + 0.2f * (float)rawSampleAgc;
      // update smoothed AGC sample
      if (fabsf(tmpAgc) < 1.0f) 
        sampleAgc =  0.5f * tmpAgc + 0.5f * sampleAgc;    // fast path to zero
      else
        sampleAgc += agcSampleSmooth[AGC_preset] * (tmpAgc - sampleAgc); // smooth path

      sampleAgc = fabsf(sampleAgc);                                      // // make sure we have a positive value
      last_soundAgc = soundAgc;
    } // agcAvg()

    // post-processing and filtering of MIC sample (micDataReal) from FFTcode()
    void getSample()
    {
      float    sampleAdj;           // Gain adjusted sample value
      float    tmpSample;           // An interim sample variable used for calculations.
#ifdef WLEDMM_FASTPATH
      constexpr float weighting = 0.35f;  // slightly reduced filter strength, to reduce audio latency
      constexpr float weighting2 = 0.25f;
#else
      const float weighting = 0.2f; // Exponential filter weighting. Will be adjustable in a future release.
      const float weighting2 = 0.073f; // Exponential filter weighting, for rising signal (a bit more robust against spikes)
#endif
      const int   AGC_preset = (soundAgc > 0)? (soundAgc-1): 0; // make sure the _compiler_ knows this value will not change while we are inside the function
      static bool isFrozen = false;
      static bool haveSilence = true;
      static unsigned long lastSoundTime = 0; // for delaying un-freeze
      static unsigned long startuptime = 0;   // "fast freeze" mode: do not interfere during first 12 seconds (filter startup time) 

      #ifdef WLED_DISABLE_SOUND
        micIn = inoise8(millis(), millis());          // Simulated analog read
        micDataReal = micIn;
      #else
        #ifdef ARDUINO_ARCH_ESP32
        micIn = int(micDataReal);      // micDataSm = ((micData * 3) + micData)/4;
        #else
        // this is the minimal code for reading analog mic input on 8266.
        // warning!! Absolutely experimental code. Audio on 8266 is still not working. Expects a million follow-on problems. 
        static unsigned long lastAnalogTime = 0;
        static float lastAnalogValue = 0.0f;
        if (millis() - lastAnalogTime > 20) {
            micDataReal = analogRead(A0); // read one sample with 10bit resolution. This is a dirty hack, supporting volumereactive effects only.
            lastAnalogTime = millis();
            lastAnalogValue = micDataReal;
            yield();
        } else micDataReal = lastAnalogValue;
        micIn = int(micDataReal);
        #endif
      #endif

      if (startuptime == 0) startuptime = millis();   // fast freeze mode - remember filter startup time
      if ((micLevelMethod < 1) || !isFrozen) {        // following the input level, UNLESS mic Level was frozen
        micLev += (micDataReal-micLev) / 12288.0f;
      }

      if(micDataReal < (micLev-0.24)) {                    // MicLev above input signal:
        micLev = ((micLev * 31.0f) + micDataReal) / 32.0f; // always align MicLev to lowest input signal
        if (!haveSilence) isFrozen = true;                 // freeze mode: freeze micLevel so it cannot rise again
      }

      micIn -= micLev;                                  // Let's center it to 0 now
      // Using an exponential filter to smooth out the signal. We'll add controls for this in a future release.
      float micInNoDC = fabsf(micDataReal - micLev);

      if ((micInNoDC > expAdjF) && (expAdjF > soundSquelch))               // MicIn rising, and above squelch threshold?
        expAdjF = (weighting2 * micInNoDC + (1.0f-weighting2) * expAdjF);  // rise slower
      else
        expAdjF = (weighting * micInNoDC + (1.0f-weighting) * expAdjF);    // fall faster

      expAdjF = fabsf(expAdjF);                         // Now (!) take the absolute value

      if ((micLevelMethod == 2) && !haveSilence && (expAdjF >= (1.5f * float(soundSquelch)))) 
        isFrozen = true;    // fast freeze mode: freeze micLevel once the volume rises 50% above squelch

      //expAdjF = (micInNoDC <= soundSquelch) ? 0: expAdjF; // simple noise gate - experimental
      expAdjF = (expAdjF <= soundSquelch) ? 0: expAdjF; // simple noise gate
      if ((soundSquelch == 0) && (expAdjF < 0.25f)) expAdjF = 0; // do something meaningfull when "squelch = 0"

      if (expAdjF <= 0.5f) 
        haveSilence = true;
      else {
        lastSoundTime = millis();
        haveSilence = false;
      }

      // un-freeze micLev
      if  (micLevelMethod == 0) isFrozen = false;
      if ((micLevelMethod == 1) && isFrozen && haveSilence && ((millis() - lastSoundTime) > 4000)) isFrozen = false;  // normal freeze: 4 seconds silence needed
      if ((micLevelMethod == 2) && isFrozen && haveSilence && ((millis() - lastSoundTime) > 6000)) isFrozen = false;  // fast freeze: 6 seconds silence needed
      if ((micLevelMethod == 2) && (millis() - startuptime < 12000)) isFrozen = false;   // fast freeze: no freeze in first 12 seconds (filter startup phase)

      tmpSample = expAdjF;
      micIn = abs(micIn);                               // And get the absolute value of each sample

      sampleAdj = tmpSample * sampleGain / 40.0f * inputLevel/128.0f + tmpSample / 16.0f; // Adjust the gain. with inputLevel adjustment
      sampleReal = tmpSample;

      sampleAdj = fmax(fmin(sampleAdj, 255), 0);        // Question: why are we limiting the value to 8 bits ???
      sampleRaw = (int16_t)sampleAdj;                   // ONLY update sample ONCE!!!!

      // keep "peak" sample, but decay value if current sample is below peak
      if ((sampleMax < sampleReal) && (sampleReal > 0.5f)) {
        sampleMax = sampleMax + 0.5f * (sampleReal - sampleMax);  // new peak - with some filtering
#if 1
        // another simple way to detect samplePeak - cannot detect beats, but reacts on peak volume
        if (((binNum < 12) || ((maxVol < 1))) && (millis() - timeOfPeak > 80) && (sampleAvg > 1)) {
          samplePeak    = true;
          timeOfPeak    = millis();
          udpSamplePeak = true;
        }
#endif
      } else {
        if ((multAgc*sampleMax > agcZoneStop[AGC_preset]) && (soundAgc > 0))
          sampleMax += 0.5f * (sampleReal - sampleMax);        // over AGC Zone - get back quickly
        else
          sampleMax *= agcSampleDecay[AGC_preset];             // signal to zero --> 5-8sec
      }
      if (sampleMax < 0.5f) sampleMax = 0.0f;

      sampleAvg = ((sampleAvg * 15.0f) + sampleAdj) / 16.0f;   // Smooth it out over the last 16 samples.
      sampleAvg = fabsf(sampleAvg);                            // make sure we have a positive value
    } // getSample()


    // current sensitivity, based on AGC gain (multAgc)
    float getSensitivity()
    {
      // start with AGC gain factor
      float tmpSound = multAgc;
      // experimental: this gives you a calculated "real gain"
      // if ((sampleAvg> 1.0) && (sampleReal > 0.05)) tmpSound = (float)sampleRaw / sampleReal;    // calculate gain from sampleReal 
      // else tmpSound = ((float)sampleGain/40.0f * (float)inputLevel/128.0f) + 1.0f/16.0f;        // silence --> use values from user settings

      if (soundAgc == 0)
        tmpSound = ((float)sampleGain/40.0f * (float)inputLevel/128.0f) + 1.0f/16.0f;   // AGC off -> use non-AGC gain from presets
      else
        tmpSound /= (float)sampleGain/40.0f + 1.0f/16.0f;                               // AGC ON -> scale value so 1 = middle value

      // scale to 0..255. Actually I'm not absolutely happy with this, but it works
      if (tmpSound > 1.0) tmpSound = sqrtf(tmpSound);
      if (tmpSound > 1.25) tmpSound = ((tmpSound-1.25f)/3.42f) +1.25f;
      // we have a value now that should be between 0 and 4 (representing gain 1/16 ... 16.0)
      return fminf(fmaxf(128.0*tmpSound -6.0f, 0), 255.0);        // return scaled non-inverted value // "-6" to ignore values below 1/24
    }

    // estimate sound pressure, based on some assumptions : 
    //   * sample max = 32676 -> Acoustic overload point  --> 105db ==> 255
    //   * sample < squelch   -> just above hearing level -->   5db ==> 0
    // see https://en.wikipedia.org/wiki/Sound_pressure#Examples_of_sound_pressure
    // use with I2S digital microphones. Expect stupid values for analog in, and with Line-In !!
    float estimatePressure() {
      // some constants
      constexpr float logMinSample = 0.8329091229351f; // ln(2.3)
      constexpr float sampleMin = 2.3f;
      constexpr float logMaxSample = 10.1895683436f; // ln(32767 - 6144)
      constexpr float sampleMax = 32767.0f - 6144.0f;

      // take the max sample from last I2S batch.
      float micSampleMax = fabsf(sampleReal);      // from getSample() - nice results, however a bit distorted by MicLev processing
      //float micSampleMax = fabsf(micDataReal);   // from FFTCode() - better source, but more flickering
      if (dmType == 0) micSampleMax *= 2.0f;       // correction for ADC analog
      //if (dmType == 4) micSampleMax *= 16.0f;      // correction for I2S Line-In
      if (dmType == 5) micSampleMax *= 2.0f;       // correction for PDM
      if (dmType == 4) {               // I2S Line-In. This is a dirty trick to make sound pressure look interesting for line-in (which doesn't have "sound pressure" as its not a microphone)
        micSampleMax /= 11.0f;         // reduce to max 128
        micSampleMax *= micSampleMax;  // blow up --> max 16000
      }
      // make sure we are in expected ranges
      if(micSampleMax <= sampleMin) return 0.0f;
      if(micSampleMax >= sampleMax) return 255.0f;

      // apply logarithmic scaling
      float scaledvalue = logf(micSampleMax);
      scaledvalue = (scaledvalue - logMinSample) / (logMaxSample - logMinSample); // 0...1
      return fminf(fmaxf(256.0*scaledvalue, 0), 255.0);        // scaled value
    }
#endif


    /* Limits the dynamics of volumeSmth (= sampleAvg or sampleAgc). 
     * does not affect FFTResult[] or volumeRaw ( = sample or rawSampleAgc) 
    */
    // effects: Gravimeter, Gravcenter, Gravcentric, Noisefire, Plasmoid, Freqpixels, Freqwave, Gravfreq, (2D Swirl, 2D Waverly)
    void limitSampleDynamics(void) {
      const float bigChange = 196;                  // just a representative number - a large, expected sample value
      static unsigned long last_time = 0;
      static float last_volumeSmth = 0.0f;

      if (limiterOn == false) return;

      long delta_time = millis() - last_time;
      delta_time = constrain(delta_time , 1, 1000); // below 1ms -> 1ms; above 1sec -> silly lil hick-up
      float deltaSample = volumeSmth - last_volumeSmth;

      if (attackTime > 0) {                         // user has defined attack time > 0
        float maxAttack =   bigChange * float(delta_time) / float(attackTime);
        if (deltaSample > maxAttack) deltaSample = maxAttack;
      }
      if (decayTime > 0) {                          // user has defined decay time > 0
        float maxDecay  = - bigChange * float(delta_time) / float(decayTime);
        if (deltaSample < maxDecay) deltaSample = maxDecay;
      }

      volumeSmth = last_volumeSmth + deltaSample; 

      last_volumeSmth = volumeSmth;
      last_time = millis();
    }

    // MM experimental: limiter to smooth GEQ samples (only for UDP sound receiver mode)
    //   target value (if gotNewSample) : fftCalc
    //   last filtered value: fftAvg
    void limitGEQDynamics(bool gotNewSample) {
      constexpr float bigChange = 202;                  // just a representative number - a large, expected sample value
      constexpr float smooth = 0.8f;                    // a bit of filtering
      static unsigned long last_time = 0;

      if (limiterOn == false) return;

      if (gotNewSample) { // take new FFT samples as target values
        for(unsigned i=0; i < NUM_GEQ_CHANNELS; i++) {
          fftCalc[i] = fftResult[i];
          fftResult[i] = fftAvg[i];
        }
      }

      long delta_time = millis() - last_time;
      delta_time = constrain(delta_time , 1, 1000); // below 1ms -> 1ms; above 1sec -> silly lil hick-up        
      float maxAttack = (attackTime <= 0) ?  255.0f : (bigChange * float(delta_time) / float(attackTime));
      float maxDecay  = (decayTime <= 0)  ? -255.0f : (-bigChange * float(delta_time) / float(decayTime));

      for(unsigned i=0; i < NUM_GEQ_CHANNELS; i++) {
        float deltaSample = fftCalc[i] - fftAvg[i];
        if (deltaSample > maxAttack) deltaSample = maxAttack;
        if (deltaSample < maxDecay) deltaSample = maxDecay;
        deltaSample = deltaSample * smooth;
        fftAvg[i] = fmaxf(0.0f, fminf(255.0f, fftAvg[i] + deltaSample));
        fftResult[i] = fftAvg[i];
      }
      last_time = millis();
    }

    //////////////////////
    // UDP Sound Sync   //
    //////////////////////

    // try to establish UDP sound sync connection
    void connectUDPSoundSync(void) {
      // This function tries to establish a UDP sync connection if needed
      // necessary as we also want to transmit in "AP Mode", but the standard "connected()" callback only reacts on STA connection
      static unsigned long last_connection_attempt = 0;

      if ((audioSyncPort <= 0) || (audioSyncEnabled == AUDIOSYNC_NONE)) return;  // Sound Sync not enabled
      if (!(apActive || WLED_CONNECTED || interfacesInited))  {
        if (udpSyncConnected) {
          udpSyncConnected = false;
          fftUdp.stop();
          receivedFormat = 0;
          DEBUGSR_PRINTLN(F("AR connectUDPSoundSync(): connection lost, UDP closed."));
        }
        return;                           // neither AP nor other connections available
      }
      if (udpSyncConnected) return;                                          // already connected
      if (millis() - last_connection_attempt < 15000) return;                // only try once in 15 seconds
      if (updateIsRunning) return;                                           // don't reconnect during OTA

      // if we arrive here, we need a UDP connection but don't have one
      last_connection_attempt = millis();
      connected(); // try to start UDP
    }
#ifdef ARDUINO_ARCH_ESP32
    void transmitAudioData()
    {
      if (!udpSyncConnected) return;
      static uint8_t frameCounter = 0;
      //DEBUGSR_PRINTLN("Transmitting UDP Mic Packet");

      audioSyncPacket transmitData;
      memset(reinterpret_cast<void *>(&transmitData), 0, sizeof(transmitData)); // make sure that the packet - including "invisible" padding bytes added by the compiler - is fully initialized

      strncpy_P(transmitData.header, PSTR(UDP_SYNC_HEADER), 6);
      // transmit samples that were not modified by limitSampleDynamics()
      transmitData.sampleRaw   = (soundAgc) ? rawSampleAgc: sampleRaw;
      transmitData.sampleSmth  = (soundAgc) ? sampleAgc   : sampleAvg;
      transmitData.samplePeak  = udpSamplePeak ? 1:0;
      udpSamplePeak            = false;           // Reset udpSamplePeak after we've transmitted it
      transmitData.frameCounter = frameCounter;
      transmitData.zeroCrossingCount = zeroCrossingCount;

      for (int i = 0; i < NUM_GEQ_CHANNELS; i++) {
        transmitData.fftResult[i] = fftResult[i];
      }

      transmitData.FFT_Magnitude = my_magnitude;
      transmitData.FFT_MajorPeak = FFT_MajorPeak;

      if (fftUdp.beginMulticastPacket() != 0) { // beginMulticastPacket returns 0 in case of error
        fftUdp.write(reinterpret_cast<uint8_t *>(&transmitData), sizeof(transmitData));
        fftUdp.endPacket();
      }
      
      frameCounter++;
    } // transmitAudioData()
#endif
    static bool isValidUdpSyncVersion(const char *header) {
      return strncmp_P(header, UDP_SYNC_HEADER, 6) == 0;
    }
    static bool isValidUdpSyncVersion_v1(const char *header) {
      return strncmp_P(header, UDP_SYNC_HEADER_v1, 6) == 0;
    }

    bool decodeAudioData(int packetSize, uint8_t *fftBuff) {
      if((0 == packetSize) || (nullptr == fftBuff)) return false; // sanity check
      audioSyncPacket *receivedPacket = reinterpret_cast<audioSyncPacket*>(fftBuff);

      // validate sequence, discard out-of-sequence packets
      static uint8_t lastFrameCounter = 0;
      // add info for UI
      if ((receivedPacket->frameCounter > 0) && (lastFrameCounter > 0)) receivedFormat = 3; // v2+
      else receivedFormat = 2; // v2
      // check sequence
      bool sequenceOK = false;
      if(receivedPacket->frameCounter > lastFrameCounter) sequenceOK = true;                  // sequence OK
      if((lastFrameCounter < 12) && (receivedPacket->frameCounter > 248)) sequenceOK = false; // prevent sequence "roll-back" due to late packets (1->254)
      if((lastFrameCounter > 248) && (receivedPacket->frameCounter < 12)) sequenceOK = true;  // handle roll-over (255 -> 0)
      if(audioSyncSequence == false) sequenceOK = true;                                       // sequence checking disabled by user
      if((sequenceOK == false) && (receivedPacket->frameCounter != 0)) {                      // always accept "0" - its the legacy value
        DEBUGSR_PRINTF("Skipping audio frame out of order or duplicated - %u vs %u\n", lastFrameCounter, receivedPacket->frameCounter);
        return false;   // reject out-of sequence frame
      }
      else {
        lastFrameCounter = receivedPacket->frameCounter;
      }

      // update samples for effects
      volumeSmth   = fmaxf(receivedPacket->sampleSmth, 0.0f);
      volumeRaw    = fmaxf(receivedPacket->sampleRaw, 0.0f);
#ifdef ARDUINO_ARCH_ESP32
      // update internal samples
      sampleRaw    = volumeRaw;
      sampleAvg    = volumeSmth;
      rawSampleAgc = volumeRaw;
      sampleAgc    = volumeSmth;
      multAgc      = 1.0f;
#endif
      // Only change samplePeak IF it's currently false.
      // If it's true already, then the animation still needs to respond.
      autoResetPeak();
      if (!samplePeak) {
            samplePeak = receivedPacket->samplePeak >0 ? true:false;
            if (samplePeak) timeOfPeak = millis();
            //userVar1 = samplePeak;
      }
      //These values are only computed by ESP32
      for (int i = 0; i < NUM_GEQ_CHANNELS; i++) fftResult[i] = receivedPacket->fftResult[i];
      my_magnitude  = fmaxf(receivedPacket->FFT_Magnitude, 0.0f);
      FFT_Magnitude = my_magnitude;
      FFT_MajorPeak = constrain(receivedPacket->FFT_MajorPeak, 1.0f, 11025.0f);  // restrict value to range expected by effects
      soundPressure = volumeSmth; // substitute - V2 format does not (yet) include this value
      agcSensitivity = 128.0f; // substitute - V2 format does not (yet) include this value
      zeroCrossingCount = receivedPacket->zeroCrossingCount;

      return true;
    }

    void decodeAudioData_v1(int packetSize, uint8_t *fftBuff) {
      audioSyncPacket_v1 *receivedPacket = reinterpret_cast<audioSyncPacket_v1*>(fftBuff);
      // update samples for effects
      volumeSmth   = fmaxf(receivedPacket->sampleAgc, 0.0f);
      volumeRaw    = volumeSmth;   // V1 format does not have "raw" AGC sample
#ifdef ARDUINO_ARCH_ESP32
      // update internal samples
      sampleRaw    = fmaxf(receivedPacket->sampleRaw, 0.0f);
      sampleAvg    = fmaxf(receivedPacket->sampleAvg, 0.0f);;
      sampleAgc    = volumeSmth;
      rawSampleAgc = volumeRaw;
      multAgc      = 1.0f;   
#endif
      // Only change samplePeak IF it's currently false.
      // If it's true already, then the animation still needs to respond.
      autoResetPeak();
      if (!samplePeak) {
            samplePeak = receivedPacket->samplePeak >0 ? true:false;
            if (samplePeak) timeOfPeak = millis();
            //userVar1 = samplePeak;
      }
      //These values are only available on the ESP32
      for (int i = 0; i < NUM_GEQ_CHANNELS; i++) fftResult[i] = receivedPacket->fftResult[i];
      my_magnitude  = fmaxf(receivedPacket->FFT_Magnitude, 0.0);
      FFT_Magnitude = my_magnitude;
      FFT_MajorPeak = constrain(receivedPacket->FFT_MajorPeak, 1.0, 11025.0);  // restrict value to range expected by effects
      soundPressure = volumeSmth; // substitute - V1 format does not include this value
      agcSensitivity = 128.0f; // substitute - V1 format does not include this value
    }

    bool receiveAudioData()   // check & process new data. return TRUE in case that new audio data was received. 
    {
      if (!udpSyncConnected) return false;
      bool haveFreshData = false;

      size_t packetSize = 0;
      // WLEDMM use exception handler to catch out-of-memory errors
      #if __cpp_exceptions
        try{
          packetSize = fftUdp.parsePacket();
        } catch(...) {
          packetSize = 0; // low heap memory -> discard packet.
#ifdef ARDUINO_ARCH_ESP32
          fftUdp.flush();  // this does not work on 8266
#endif
          DEBUG_PRINTLN(F("receiveAudioData: parsePacket out of memory exception caught!"));
          USER_FLUSH();
        }
      #else
        packetSize = fftUdp.parsePacket();
      #endif

#ifdef ARDUINO_ARCH_ESP32
      if ((packetSize > 0) && ((packetSize < 5) || (packetSize > UDPSOUND_MAX_PACKET))) fftUdp.flush(); // discard invalid packets (too small or too big)
#endif
      if ((packetSize > 5) && (packetSize <= UDPSOUND_MAX_PACKET)) {
        static uint8_t fftUdpBuffer[UDPSOUND_MAX_PACKET+1] = { 0 }; // static buffer for receiving, to reuse the same memory and avoid heap fragmentation
        //DEBUGSR_PRINTLN("Received UDP Sync Packet");
        fftUdp.read(fftUdpBuffer, packetSize);

        // VERIFY THAT THIS IS A COMPATIBLE PACKET
        if (packetSize == sizeof(audioSyncPacket) && (isValidUdpSyncVersion((const char *)fftUdpBuffer))) {
          receivedFormat = 2;
          haveFreshData = decodeAudioData(packetSize, fftUdpBuffer);
          //DEBUGSR_PRINTLN("Finished parsing UDP Sync Packet v2");
        } else {
          if (packetSize == sizeof(audioSyncPacket_v1) && (isValidUdpSyncVersion_v1((const char *)fftUdpBuffer))) {
            decodeAudioData_v1(packetSize, fftUdpBuffer);
            receivedFormat = 1;
            //DEBUGSR_PRINTLN("Finished parsing UDP Sync Packet v1");
            haveFreshData = true;
          } else receivedFormat = 0; // unknown format
        }
      }
      return haveFreshData;
    }


    //////////////////////
    // usermod functions//
    //////////////////////

  public:
    //Functions called by WLED or other usermods

    /*
     * setup() is called once at boot. WiFi is not yet connected at this point.
     * You can use it to initialize variables, sensors or similar.
     * It is called *AFTER* readFromConfig()
     */
    void setup()
    {
      disableSoundProcessing = true; // just to be sure
      if (!initDone) {
        // usermod exchangeable data
        // we will assign all usermod exportable data here as pointers to original variables or arrays and allocate memory for pointers
        um_data = new um_data_t;
        um_data->u_size = 12;
        um_data->u_type = new um_types_t[um_data->u_size];
        um_data->u_data = new void*[um_data->u_size];
        um_data->u_data[0] = &volumeSmth;      //*used (New)
        um_data->u_type[0] = UMT_FLOAT;
        um_data->u_data[1] = &volumeRaw;       // used (New)
        um_data->u_type[1] = UMT_UINT16;
        um_data->u_data[2] = fftResult;        //*used (Blurz, DJ Light, Noisemove, GEQ_base, 2D Funky Plank, Akemi)
        um_data->u_type[2] = UMT_BYTE_ARR;
        um_data->u_data[3] = &samplePeak;      //*used (Puddlepeak, Ripplepeak, Waterfall)
        um_data->u_type[3] = UMT_BYTE;
        um_data->u_data[4] = &FFT_MajorPeak;   //*used (Ripplepeak, Freqmap, Freqmatrix, Freqpixels, Freqwave, Gravfreq, Rocktaves, Waterfall)
        um_data->u_type[4] = UMT_FLOAT;
        um_data->u_data[5] = &my_magnitude;    // used (New)
        um_data->u_type[5] = UMT_FLOAT;
#ifdef ARDUINO_ARCH_ESP32
        um_data->u_data[6] = &maxVol;          // assigned in effect function from UI element!!! (Puddlepeak, Ripplepeak, Waterfall)
        um_data->u_type[6] = UMT_BYTE;
        um_data->u_data[7] = &binNum;          // assigned in effect function from UI element!!! (Puddlepeak, Ripplepeak, Waterfall)
        um_data->u_type[7] = UMT_BYTE;
        um_data->u_data[8] = &FFT_MajPeakSmth; // new
        um_data->u_type[8] = UMT_FLOAT;
        um_data->u_data[9]  = &soundPressure;  // used (New)
        um_data->u_type[9]  = UMT_FLOAT;
        um_data->u_data[10] = &agcSensitivity; // used (New)
        um_data->u_type[10] = UMT_FLOAT;
        um_data->u_data[11] = &zeroCrossingCount;
        um_data->u_type[11] = UMT_UINT16;
#else
       // ESP8266 
        // See https://github.com/MoonModules/WLED/pull/60#issuecomment-1666972133 for explanation of these alternative sources of data

        um_data->u_data[6] = &maxVol;          // assigned in effect function from UI element!!! (Puddlepeak, Ripplepeak, Waterfall)
        um_data->u_type[6] = UMT_BYTE;
        um_data->u_data[7] = &binNum;          // assigned in effect function from UI element!!! (Puddlepeak, Ripplepeak, Waterfall)
        um_data->u_type[7] = UMT_BYTE;
        um_data->u_data[8] = &FFT_MajorPeak; // new - substitute for FFT_MajPeakSmth
        um_data->u_type[8] = UMT_FLOAT;
        um_data->u_data[9]  = &volumeSmth;  // used (New) - substitute for soundPressure
        um_data->u_type[9]  = UMT_FLOAT;
        um_data->u_data[10] = &agcSensitivity; // used (New) - dummy value (128 => 50%)
        um_data->u_type[10] = UMT_FLOAT;
        um_data->u_data[11] = &zeroCrossingCount;
        um_data->u_type[11] = UMT_UINT16;
#endif
      }

#ifdef ARDUINO_ARCH_ESP32

      // Reset I2S peripheral for good measure
      i2s_driver_uninstall(I2S_NUM_0);   // E (696) I2S: i2s_driver_uninstall(2006): I2S port 0 has not installed
      #if !defined(CONFIG_IDF_TARGET_ESP32C3)
        delay(100);
        periph_module_reset(PERIPH_I2S0_MODULE);   // not possible on -C3
      #endif
      delay(100);         // Give that poor microphone some time to setup.

      #if !defined(CONFIG_IDF_TARGET_ESP32S2) && !defined(CONFIG_IDF_TARGET_ESP32C3)
        if ((i2sckPin == I2S_PIN_NO_CHANGE) && (i2ssdPin >= 0) && (i2swsPin >= 0) 
            && ((dmType == 1) || (dmType == 4)) ) dmType = 51;   // dummy user support: SCK == -1 --means--> PDM microphone
      #endif

      useInputFilter = 2; // default: DC blocker
      switch (dmType) {
      #if defined(CONFIG_IDF_TARGET_ESP32S2) || defined(CONFIG_IDF_TARGET_ESP32C3) || defined(CONFIG_IDF_TARGET_ESP32S3)
        // stub cases for not-yet-supported I2S modes on other ESP32 chips
        case 0:  //ADC analog
        #if defined(CONFIG_IDF_TARGET_ESP32S2) || defined(CONFIG_IDF_TARGET_ESP32C3)
        case 5:  //PDM Microphone
        case 51: //legacy PDM Microphone
        #endif
      #endif
        case 1:
          DEBUGSR_PRINT(F("AR: Generic I2S Microphone - ")); DEBUGSR_PRINTLN(F(I2S_MIC_CHANNEL_TEXT));
          audioSource = new I2SSource(SAMPLE_RATE, BLOCK_SIZE);
          delay(100);
          if (audioSource) audioSource->initialize(i2swsPin, i2ssdPin, i2sckPin);
          break;
        case 2:
          DEBUGSR_PRINTLN(F("AR: ES7243 Microphone (right channel only)."));
          //useInputFilter = 0; // in case you need to disable low-cut software filtering
          audioSource = new ES7243(SAMPLE_RATE, BLOCK_SIZE);
          delay(100);
          // WLEDMM align global pins
          if ((sdaPin >= 0) && (i2c_sda < 0)) i2c_sda = sdaPin; // copy usermod prefs into globals (if globals not defined)
          if ((sclPin >= 0) && (i2c_scl < 0)) i2c_scl = sclPin;
          if (i2c_sda >= 0) sdaPin = -1;                        // -1 = use global
          if (i2c_scl >= 0) sclPin = -1;

          if (audioSource) audioSource->initialize(i2swsPin, i2ssdPin, i2sckPin, mclkPin);
          break;
        case 3:
          DEBUGSR_PRINT(F("AR: SPH0645 Microphone - ")); DEBUGSR_PRINTLN(F(I2S_MIC_CHANNEL_TEXT));
          audioSource = new SPH0654(SAMPLE_RATE, BLOCK_SIZE);
          delay(100);
          audioSource->initialize(i2swsPin, i2ssdPin, i2sckPin);
          break;
        case 4:
          DEBUGSR_PRINT(F("AR: Generic I2S Microphone with Master Clock - ")); DEBUGSR_PRINTLN(F(I2S_MIC_CHANNEL_TEXT));
          audioSource = new I2SSource(SAMPLE_RATE, BLOCK_SIZE, 1.0f/24.0f);
          //audioSource = new I2SSource(SAMPLE_RATE, BLOCK_SIZE, 1.0f/24.0f, false);   // I2S SLAVE mode - does not work, unfortunately
          delay(100);
          if (audioSource) audioSource->initialize(i2swsPin, i2ssdPin, i2sckPin, mclkPin);
          break;
        #if  !defined(CONFIG_IDF_TARGET_ESP32S2) && !defined(CONFIG_IDF_TARGET_ESP32C3)
        case 5:
          DEBUGSR_PRINT(F("AR: I2S PDM Microphone - ")); DEBUGSR_PRINTLN(F(I2S_PDM_MIC_CHANNEL_TEXT));
          audioSource = new I2SSource(SAMPLE_RATE, BLOCK_SIZE, 1.0f/4.0f);
          useInputFilter = 1;  // PDM bandpass filter - this reduces the noise floor on SPM1423 from 5% Vpp (~380) down to 0.05% Vpp (~5)
          delay(100);
          if (audioSource) audioSource->initialize(i2swsPin, i2ssdPin);
          break;
        case 51:
          DEBUGSR_PRINT(F("AR: Legacy PDM Microphone - ")); DEBUGSR_PRINTLN(F(I2S_PDM_MIC_CHANNEL_TEXT));
          audioSource = new I2SSource(SAMPLE_RATE, BLOCK_SIZE, 1.0f);
          useInputFilter = 1;  // PDM bandpass filter
          delay(100);
          if (audioSource) audioSource->initialize(i2swsPin, i2ssdPin);
          break;
        #endif
        case 6:
        #ifdef use_es8388_mic
          DEBUGSR_PRINTLN(F("AR: ES8388 Source (Mic)"));
        #else
          DEBUGSR_PRINTLN(F("AR: ES8388 Source (Line-In)"));
        #endif
          audioSource = new ES8388Source(SAMPLE_RATE, BLOCK_SIZE, 1.0f);
          //useInputFilter = 0; // to disable low-cut software filtering and restore previous behaviour
          delay(100);
          // WLEDMM align global pins
          if ((sdaPin >= 0) && (i2c_sda < 0)) i2c_sda = sdaPin; // copy usermod prefs into globals (if globals not defined)
          if ((sclPin >= 0) && (i2c_scl < 0)) i2c_scl = sclPin;
          if (i2c_sda >= 0) sdaPin = -1;                        // -1 = use global
          if (i2c_scl >= 0) sclPin = -1;

          if (audioSource) audioSource->initialize(i2swsPin, i2ssdPin, i2sckPin, mclkPin);
          break;
        case 7:
        #ifdef use_wm8978_mic
          DEBUGSR_PRINTLN(F("AR: WM8978 Source (Mic)"));
        #else
          DEBUGSR_PRINTLN(F("AR: WM8978 Source (Line-In)"));
        #endif
          audioSource = new WM8978Source(SAMPLE_RATE, BLOCK_SIZE, 1.0f);
          //useInputFilter = 0; // to disable low-cut software filtering and restore previous behaviour
          delay(100);
          // WLEDMM align global pins
          if ((sdaPin >= 0) && (i2c_sda < 0)) i2c_sda = sdaPin; // copy usermod prefs into globals (if globals not defined)
          if ((sclPin >= 0) && (i2c_scl < 0)) i2c_scl = sclPin;
          if (i2c_sda >= 0) sdaPin = -1;                        // -1 = use global
          if (i2c_scl >= 0) sclPin = -1;

          if (audioSource) audioSource->initialize(i2swsPin, i2ssdPin, i2sckPin, mclkPin);
          break;

        #if  !defined(CONFIG_IDF_TARGET_ESP32S2) && !defined(CONFIG_IDF_TARGET_ESP32C3) && !defined(CONFIG_IDF_TARGET_ESP32S3)
        // ADC over I2S is only possible on "classic" ESP32
        case 0:
        default:
          DEBUGSR_PRINTLN(F("AR: Analog Microphone (left channel only)."));
          useInputFilter = 1;  // PDM bandpass filter seems to work well for analog, too
          audioSource = new I2SAdcSource(SAMPLE_RATE, BLOCK_SIZE);
          delay(100);
          if (audioSource) audioSource->initialize(audioPin);
          break;
        #endif
      }
      delay(250); // give microphone enough time to initialise

      if (!audioSource) enabled = false;                 // audio failed to initialise
#endif
      if (enabled) onUpdateBegin(false);                 // create FFT task, and initialize network

#ifdef ARDUINO_ARCH_ESP32
      if (FFT_Task == nullptr) enabled = false;          // FFT task creation failed
      if((!audioSource) || (!audioSource->isInitialized())) {  // audio source failed to initialize. Still stay "enabled", as there might be input arriving via UDP Sound Sync 
      #ifdef WLED_DEBUG
        DEBUG_PRINTLN(F("AR: Failed to initialize sound input driver. Please check input PIN settings."));
      #else
        USER_PRINTLN(F("AR: Failed to initialize sound input driver. Please check input PIN settings."));
      #endif
        disableSoundProcessing = true;
      } else {
        USER_PRINTLN(F("AR: sound input driver initialized successfully."));        
      }
#endif
      if (enabled) disableSoundProcessing = false;       // all good - enable audio processing
      // try to start UDP
      last_UDPTime = 0;
      receivedFormat = 0;
      delay(100);
      if (enabled) connectUDPSoundSync();
      initDone = true;
      DEBUGSR_PRINT(F("AR: init done, enabled = "));
      DEBUGSR_PRINTLN(enabled ? F("true.") : F("false."));
      USER_FLUSH();

      // dump audiosync data layout
      #if defined(SR_DEBUG)
      {
        audioSyncPacket data;
        USER_PRINTF("\naudioSyncPacket_v1 size = %d\n", sizeof(audioSyncPacket_v1));                                                         // size 88
        USER_PRINTF("audioSyncPacket size = %d\n", sizeof(audioSyncPacket));                                                               // size 44
        USER_PRINTF("|  char    header[6]     offset = %2d   size = %2d\n", offsetof(audioSyncPacket, header[0]), sizeof(data.header));           // offset  0 size 6
        USER_PRINTF("|  uint8_t gap1[2]       offset = %2d   size = %2d\n", offsetof(audioSyncPacket, gap1[0]), sizeof(data.gap1));               // offset  6 size 2
        USER_PRINTF("|  float   sampleRaw     offset = %2d   size = %2d\n", offsetof(audioSyncPacket, sampleRaw), sizeof(data.sampleRaw));        // offset  8 size 4
        USER_PRINTF("|  float   sampleSmth    offset = %2d   size = %2d\n", offsetof(audioSyncPacket, sampleSmth), sizeof(data.sampleSmth));      // offset 12 size 4
        USER_PRINTF("|  uint8_t samplePeak    offset = %2d   size = %2d\n", offsetof(audioSyncPacket, samplePeak), sizeof(data.samplePeak));      // offset 16 size 1
        USER_PRINTF("|  uint8_t frameCounter  offset = %2d   size = %2d\n", offsetof(audioSyncPacket, frameCounter), sizeof(data.frameCounter));  // offset 17 size 1
        USER_PRINTF("|  uint8_t fftResult[16] offset = %2d   size = %2d\n", offsetof(audioSyncPacket, fftResult[0]), sizeof(data.fftResult));     // offset 18 size 16
        USER_PRINTF("|  uint16_t zeroCrossingCount offset = %2d   size = %2d\n", offsetof(audioSyncPacket, zeroCrossingCount), sizeof(data.zeroCrossingCount)); // offset 34 size 2
        USER_PRINTF("|  float   FFT_Magnitude offset = %2d   size = %2d\n", offsetof(audioSyncPacket, FFT_Magnitude), sizeof(data.FFT_Magnitude));// offset 36 size 4
        USER_PRINTF("|  float   FFT_MajorPeak offset = %2d   size = %2d\n", offsetof(audioSyncPacket, FFT_MajorPeak), sizeof(data.FFT_MajorPeak));// offset 40 size 4
        USER_PRINTLN(); USER_FLUSH();
      }
      #endif

      #if defined(ARDUINO_ARCH_ESP32) && defined(SR_DEBUG)
      DEBUGSR_PRINTF("|| %-9s min free stack %d\n", pcTaskGetTaskName(NULL), uxTaskGetStackHighWaterMark(NULL)); //WLEDMM
      #endif
    }


    /*
     * connected() is called every time the WiFi is (re)connected
     * Use it to initialize network interfaces
     */
    void connected()
    {
      if (udpSyncConnected) {   // clean-up: if open, close old UDP sync connection
        udpSyncConnected = false;
        fftUdp.stop();
        receivedFormat = 0;
        DEBUGSR_PRINTLN(F("AR connected(): old UDP connection closed."));
      }
      
      if ((audioSyncPort > 0) && (audioSyncEnabled > AUDIOSYNC_NONE)) {
      #ifdef ARDUINO_ARCH_ESP32
        udpSyncConnected = fftUdp.beginMulticast(IPAddress(239, 0, 0, 1), audioSyncPort);
      #else
        udpSyncConnected = fftUdp.beginMulticast(WiFi.localIP(), IPAddress(239, 0, 0, 1), audioSyncPort);
      #endif
        receivedFormat = 0;
        if (udpSyncConnected) last_UDPTime = millis();
        if (apActive && !(WLED_CONNECTED)) {
          DEBUGSR_PRINTLN(udpSyncConnected ? F("AR connected(): UDP: connected using AP.") : F("AR connected(): UDP is disconnected (AP)."));
        } else {
          DEBUGSR_PRINTLN(udpSyncConnected ? F("AR connected(): UDP: connected to WIFI.") :  F("AR connected(): UDP is disconnected (Wifi)."));
        }
      }

      #if defined(ARDUINO_ARCH_ESP32) && defined(SR_DEBUG)
      DEBUGSR_PRINTF("|| %-9s min free stack %d\n", pcTaskGetTaskName(NULL), uxTaskGetStackHighWaterMark(NULL)); //WLEDMM
      #endif
    }


    /*
     * loop() is called continuously. Here you can check for events, read sensors, etc.
     * 
     * Tips:
     * 1. You can use "if (WLED_CONNECTED)" to check for a successful network connection.
     *    Additionally, "if (WLED_MQTT_CONNECTED)" is available to check for a connection to an MQTT broker.
     * 
     * 2. Try to avoid using the delay() function. NEVER use delays longer than 10 milliseconds.
     *    Instead, use a timer check as shown here.
     */
    void loop()
    {
      static unsigned long lastUMRun = millis();

      if (!enabled) {
        disableSoundProcessing = true;   // keep processing suspended (FFT task)
        lastUMRun = millis();            // update time keeping
        return;
      }
      // We cannot wait indefinitely before processing audio data
      if (strip.isServicing() && (millis() - lastUMRun < 2)) return;   // WLEDMM isServicing() is the critical part (be nice, but not too nice)

      // sound sync "receive or local"
      bool useNetworkAudio = false;
      if (audioSyncEnabled > AUDIOSYNC_SEND) {  // we are in "receive" or "receive+local" mode
        if (udpSyncConnected && ((millis() - last_UDPTime) <= AUDIOSYNC_IDLE_MS))
          useNetworkAudio = true;
        else
          useNetworkAudio = false;
        if (audioSyncEnabled == AUDIOSYNC_REC)
          useNetworkAudio = true;  // don't fall back to local audio in standard "receive mode"
      }

      // suspend local sound processing when "real time mode" is active (E131, UDP, ADALIGHT, ARTNET)
      if (  (realtimeOverride == REALTIME_OVERRIDE_NONE)  // please add other overrides here if needed
          &&( (realtimeMode == REALTIME_MODE_GENERIC)
            ||(realtimeMode == REALTIME_MODE_E131)
            ||(realtimeMode == REALTIME_MODE_UDP)
            ||(realtimeMode == REALTIME_MODE_ADALIGHT)
            ||(realtimeMode == REALTIME_MODE_ARTNET) ) )  // please add other modes here if needed
      {
        #ifdef WLED_DEBUG
        if ((disableSoundProcessing == false) && (audioSyncEnabled < AUDIOSYNC_REC)) {  // we just switched to "disabled"
          DEBUG_PRINTLN("[AR userLoop]  realtime mode active - audio processing suspended.");
          DEBUG_PRINTF( "               RealtimeMode = %d; RealtimeOverride = %d\n", int(realtimeMode), int(realtimeOverride));
        }
        #endif
        disableSoundProcessing = true;
        useNetworkAudio = false;
      } else {
        #if defined(ARDUINO_ARCH_ESP32) && defined(WLED_DEBUG)
        if ((disableSoundProcessing == true) && (audioSyncEnabled < AUDIOSYNC_REC) && audioSource->isInitialized()) {    // we just switched to "enabled"
          DEBUG_PRINTLN("[AR userLoop]  realtime mode ended - audio processing resumed.");
          DEBUG_PRINTF( "               RealtimeMode = %d; RealtimeOverride = %d\n", int(realtimeMode), int(realtimeOverride));
        }
        #endif
        if ((disableSoundProcessing == true) && (audioSyncEnabled != AUDIOSYNC_REC)) lastUMRun = millis();  // just left "realtime mode" - update timekeeping
        disableSoundProcessing = false;
      }

      if (audioSyncEnabled == AUDIOSYNC_REC) disableSoundProcessing = true;   // make sure everything is disabled IF in audio Receive mode
      if (audioSyncEnabled == AUDIOSYNC_SEND) disableSoundProcessing = false;  // keep running audio IF we're in audio Transmit mode
#ifdef ARDUINO_ARCH_ESP32
      if (!audioSource->isInitialized()) {                                                               // no audio source
        disableSoundProcessing = true;
        if (audioSyncEnabled > AUDIOSYNC_SEND) useNetworkAudio = true;
      }
      if ((audioSyncEnabled == AUDIOSYNC_REC_PLUS) && useNetworkAudio) disableSoundProcessing = true;   // UDP sound receiving - disable local audio

      #ifdef SR_DEBUG
      // debug info in case that task stack usage changes
      static unsigned int minLoopStackFree = UINT32_MAX;
      unsigned int stackFree = uxTaskGetStackHighWaterMark(NULL);
      if (minLoopStackFree > stackFree) {
        minLoopStackFree = stackFree;
        DEBUGSR_PRINTF("|| %-9s min free stack %d\n", pcTaskGetTaskName(NULL), minLoopStackFree); //WLEDMM
      }
      #endif

      // Only run the sampling code IF we're not in Receive mode or realtime mode
      if ((audioSyncEnabled != AUDIOSYNC_REC) && !disableSoundProcessing && !useNetworkAudio) {
        if (soundAgc > AGC_NUM_PRESETS) soundAgc = 0; // make sure that AGC preset is valid (to avoid array bounds violation)

        unsigned long t_now = millis();      // remember current time
        int userloopDelay = int(t_now - lastUMRun);
        if (lastUMRun == 0) userloopDelay=0; // startup - don't have valid data from last run.

        #if defined(SR_DEBUG)
          // complain when audio userloop has been delayed for long time. Currently we need userloop running between 500 and 1500 times per second.
          // softhack007 disabled temporarily - avoid serial console spam with MANY LEDs and low FPS
          //if ((userloopDelay > /*23*/ 65) && !disableSoundProcessing && (audioSyncEnabled == AUDIOSYNC_NONE)) {
            //DEBUG_PRINTF("[AR userLoop] hiccup detected -> was inactive for last %d millis!\n", userloopDelay);
          //}
        #endif

        // run filters, and repeat in case of loop delays (hick-up compensation)
        if (userloopDelay <2) userloopDelay = 0;      // minor glitch, no problem
        if (userloopDelay >200) userloopDelay = 200;  // limit number of filter re-runs  
        do {
          getSample();                        // run microphone sampling filters
          agcAvg(t_now - userloopDelay);      // Calculated the PI adjusted value as sampleAvg
          userloopDelay -= 2;                 // advance "simulated time" by 2ms
        } while (userloopDelay > 0);
        lastUMRun = t_now;                    // update time keeping

        // update samples for effects (raw, smooth) 
        volumeSmth = (soundAgc) ? sampleAgc   : sampleAvg;
        volumeRaw  = (soundAgc) ? rawSampleAgc: sampleRaw;
        // update FFTMagnitude, taking into account AGC amplification
        my_magnitude = FFT_Magnitude; // / 16.0f, 8.0f, 4.0f done in effects
        if (soundAgc) my_magnitude *= multAgc;
        if (volumeSmth < 1 ) my_magnitude = 0.001f;  // noise gate closed - mute

        // get AGC sensitivity and sound pressure
        static unsigned long lastEstimate = 0;
#ifdef WLEDMM_FASTPATH
        if (millis() - lastEstimate > 7) {
#else
        if (millis() - lastEstimate > 12) {
#endif
          lastEstimate = millis();
          agcSensitivity = getSensitivity();
          if (limiterOn)
            soundPressure = soundPressure + 0.38f * (estimatePressure() - soundPressure);  // dynamics limiter on -> some smoothing
          else
            soundPressure = soundPressure + 0.95f * (estimatePressure() - soundPressure);  //  dynamics limiter on -> raw value
        }
        limitSampleDynamics();
      }  // if (!disableSoundProcessing)
#endif

      autoResetPeak();          // auto-reset sample peak after strip minShowDelay
      if (!udpSyncConnected) udpSamplePeak = false;  // reset UDP samplePeak while UDP is unconnected

      connectUDPSoundSync();  // ensure we have a connection - if needed

      // UDP Microphone Sync  - receive mode
      if ((audioSyncEnabled & AUDIOSYNC_REC) && udpSyncConnected) {
          // Only run the audio listener code if we're in Receive mode
          static float syncVolumeSmth = 0;
          bool have_new_sample = false;
          if (millis() - lastTime > delayMs) {
            have_new_sample = receiveAudioData();
            if (have_new_sample) {
              last_UDPTime = millis();
              useNetworkAudio = true;  // UDP input arrived - use it
            }
            lastTime = millis();
          } else {
#ifdef ARDUINO_ARCH_ESP32
            fftUdp.flush(); // WLEDMM: Flush this if we haven't read it. Does not work on 8266.
#endif
          }
          if (useNetworkAudio) {
            if (have_new_sample) syncVolumeSmth = volumeSmth;   // remember received sample
            else volumeSmth = syncVolumeSmth;                   // restore originally received sample for next run of dynamics limiter
            limitSampleDynamics();                              // run dynamics limiter on received volumeSmth, to hide jumps and hickups
            limitGEQDynamics(have_new_sample);                  // WLEDMM experimental: smooth FFT (GEQ) samples
          }
      } else {
          receivedFormat = 0;
      }

      if (   (audioSyncEnabled & AUDIOSYNC_REC) // receive mode
          && udpSyncConnected          // connected
          && (receivedFormat > 0)      // we actually received something in the past
          && ((millis() - last_UDPTime) > 25000)) {   // close connection after 25sec idle
        udpSyncConnected = false;
        receivedFormat = 0;
        fftUdp.stop();
        volumeSmth =0.0f;
        volumeRaw =0;
        my_magnitude = 0.1; FFT_Magnitude = 0.01; FFT_MajorPeak = 2;
	soundPressure = 1.0f;
        agcSensitivity = 64.0f;
#ifdef ARDUINO_ARCH_ESP32
        multAgc = 1;
#endif
        DEBUGSR_PRINTLN(F("AR  loop(): UDP closed due to inactivity."));
      }

      #if defined(MIC_LOGGER) || defined(MIC_SAMPLING_LOG) || defined(FFT_SAMPLING_LOG)
      static unsigned long lastMicLoggerTime = 0;
      if (millis()-lastMicLoggerTime > 20) {
        lastMicLoggerTime = millis();
        logAudio();
      }
      #endif

      // Info Page: keep max sample from last 5 seconds
#ifdef ARDUINO_ARCH_ESP32
      if ((millis() -  sampleMaxTimer) > CYCLE_SAMPLEMAX) {
        sampleMaxTimer = millis();
        maxSample5sec = (0.15 * maxSample5sec) + 0.85 *((soundAgc) ? sampleAgc : sampleAvg); // reset, and start with some smoothing
        if (sampleAvg < 1) maxSample5sec = 0; // noise gate 
      } else {
         if ((sampleAvg >= 1)) maxSample5sec = fmaxf(maxSample5sec, (soundAgc) ? rawSampleAgc : sampleRaw); // follow maximum volume
      }
#else  // similar functionality for 8266 receive only - use VolumeSmth instead of raw sample data
      if ((millis() -  sampleMaxTimer) > CYCLE_SAMPLEMAX) {
        sampleMaxTimer = millis();
        maxSample5sec = (0.15 * maxSample5sec) + 0.85 * volumeSmth; // reset, and start with some smoothing
        if (volumeSmth < 1.0f) maxSample5sec = 0; // noise gate
        if (maxSample5sec < 0.0f) maxSample5sec = 0; // avoid negative values
      } else {
         if (volumeSmth >= 1.0f) maxSample5sec = fmaxf(maxSample5sec, volumeRaw); // follow maximum volume
      }
#endif

#ifdef ARDUINO_ARCH_ESP32
      //UDP Microphone Sync  - transmit mode
    #if defined(WLEDMM_FASTPATH)
      if ((audioSyncEnabled & AUDIOSYNC_SEND) && (haveNewFFTResult || (millis() - lastTime > 24))) {  // fastpath: send data once results are ready, or each 25ms as fallback (max sampling time is 23ms)
    #else
      if ((audioSyncEnabled & AUDIOSYNC_SEND) && (millis() - lastTime > 20)) {                        // standard: send data each 20ms
    #endif
        haveNewFFTResult = false; // reset notification
        // Only run the transmit code IF we're in Transmit mode
        transmitAudioData();
        lastTime = millis();
      }
#endif
    }


    bool getUMData(um_data_t **data)
    {
      if (!data || !enabled) return false; // no pointer provided by caller or not enabled -> exit
      *data = um_data;
      return true;
    }


#ifdef ARDUINO_ARCH_ESP32
    void onUpdateBegin(bool init)
    {
#ifdef WLED_DEBUG
      fftTime = sampleTime = 0;
#endif
      // gracefully suspend FFT task (if running)
      disableSoundProcessing = true;

      // reset sound data
      micDataReal = 0.0f;
      volumeRaw = 0; volumeSmth = 0;
      sampleAgc = 0; sampleAvg = 0;
      sampleRaw = 0; rawSampleAgc = 0;
      my_magnitude = 0; FFT_Magnitude = 0; FFT_MajorPeak = 1;
      multAgc = 1;
      // reset FFT data
      memset(fftCalc, 0, sizeof(fftCalc)); 
      memset(fftAvg, 0, sizeof(fftAvg)); 
      memset(fftResult, 0, sizeof(fftResult)); 
      for(int i=(init?0:1); i<NUM_GEQ_CHANNELS; i+=2) fftResult[i] = 16; // make a tiny pattern
      inputLevel = 128;                                    // reset level slider to default
      autoResetPeak();

      if (init && FFT_Task) {
        delay(25);                // WLEDMM: givesome time for I2S driver to finish sampling
        vTaskSuspend(FFT_Task);   // update is about to begin, disable task to prevent crash
        if (udpSyncConnected) {   // close UDP sync connection (if open)
          udpSyncConnected = false;
          fftUdp.stop();
          DEBUGSR_PRINTLN(F("AR onUpdateBegin(true): UDP connection closed."));
          receivedFormat = 0;
        }
      } else {
        // update has failed or create task requested
        if (FFT_Task) {
          vTaskResume(FFT_Task);
          connected(); // resume UDP
        } else
//          xTaskCreatePinnedToCore(
//          xTaskCreate(                        // no need to "pin" this task to core #0
          xTaskCreateUniversal(
            FFTcode,                          // Function to implement the task
            "FFT",                            // Name of the task
            3592,                             // Stack size in words // 3592 leaves 800-1024 bytes of task stack free
            NULL,                             // Task input parameter
            FFTTASK_PRIORITY,                 // Priority of the task
            &FFT_Task                         // Task handle
            , 0                               // Core where the task should run
          );
      }
      micDataReal = 0.0f;                     // just to be sure
      if (enabled) disableSoundProcessing = false;
      updateIsRunning = init;

      #if defined(ARDUINO_ARCH_ESP32) && defined(SR_DEBUG)
      DEBUGSR_PRINTF("|| %-9s min free stack %d\n", pcTaskGetTaskName(NULL), uxTaskGetStackHighWaterMark(NULL)); //WLEDMM
      #endif
    }

#else // reduced function for 8266
    void onUpdateBegin(bool init)
    {
      // gracefully suspend audio (if running)
      disableSoundProcessing = true;
      // reset sound data
      volumeRaw = 0; volumeSmth = 0;
      for(int i=(init?0:1); i<NUM_GEQ_CHANNELS; i+=2) fftResult[i] = 16; // make a tiny pattern
      autoResetPeak();

      if (init) {
        if (udpSyncConnected) {   // close UDP sync connection (if open)
          udpSyncConnected = false;
          fftUdp.stop();
          DEBUGSR_PRINTLN(F("AR onUpdateBegin(true): UDP connection closed."));
          receivedFormat = 0;
        }
      }
      if (enabled) disableSoundProcessing = init; // init = true means that OTA is just starting --> don't process audio
      updateIsRunning = init;
    }
#endif

#ifdef ARDUINO_ARCH_ESP32
    /**
     * handleButton() can be used to override default button behaviour. Returning true
     * will prevent button working in a default way.
     */
    bool handleButton(uint8_t b) {
      yield();
      // crude way of determining if audio input is analog
      // better would be for AudioSource to implement getType()
      if (enabled
          && dmType == 0 && audioPin>=0
          && (buttonType[b] == BTN_TYPE_ANALOG || buttonType[b] == BTN_TYPE_ANALOG_INVERTED)
         ) {
        return true;
      }
      return false;
    }
#endif

    ////////////////////////////
    // Settings and Info Page //
    ////////////////////////////

    /*
     * addToJsonInfo() can be used to add custom entries to the /json/info part of the JSON API.
     * Creating an "u" object allows you to add custom key/value pairs to the Info section of the WLED web UI.
     * Below it is shown how this could be used for e.g. a light sensor
     */
    void addToJsonInfo(JsonObject& root)
    {
#ifdef ARDUINO_ARCH_ESP32
      char myStringBuffer[16]; // buffer for snprintf() - not used yet on 8266
#endif
      JsonObject user = root["u"];
      if (user.isNull()) user = root.createNestedObject("u");

      JsonArray infoArr = user.createNestedArray(FPSTR(_name));

      String uiDomString = F("<button class=\"btn btn-xs\" onclick=\"requestJson({");
      uiDomString += FPSTR(_name);
      uiDomString += F(":{");
      uiDomString += FPSTR(_enabled);
      uiDomString += enabled ? F(":false}});\">") : F(":true}});\">");
      uiDomString += F("<i class=\"icons");
      uiDomString += enabled ? F(" on") : F(" off");
      uiDomString += F("\">&#xe08f;</i>");
      uiDomString += F("</button>");
      infoArr.add(uiDomString);

      if (enabled) {
        bool audioSyncIDLE = false; // true if sound sync is not receiving

#ifdef ARDUINO_ARCH_ESP32
        // audio sync status
        if ((audioSyncEnabled & AUDIOSYNC_REC) && (!udpSyncConnected || (millis() - last_UDPTime > AUDIOSYNC_IDLE_MS))) // connected and nothing received in 2.5sec
          audioSyncIDLE = true;
        if ((audioSource == nullptr) || (!audioSource->isInitialized()))                                   // local audio not configured
          audioSyncIDLE = false;

        // Input Level Slider
        if (disableSoundProcessing == false) {                                 // only show slider when audio processing is running
          if (soundAgc > 0) {
            infoArr = user.createNestedArray(F("GEQ Input Level"));           // if AGC is on, this slider only affects fftResult[] frequencies
            // show slider value as a number
            float post_gain = (float)inputLevel/128.0f;
            if (post_gain < 1.0f) post_gain = ((post_gain -1.0f) * 0.8f) +1.0f;
            post_gain = roundf(post_gain * 100.0f);
            snprintf_P(myStringBuffer, 15, PSTR("%3.0f %%"), post_gain);
            infoArr.add(myStringBuffer);
          } else {
            infoArr = user.createNestedArray(F("Audio Input Level"));
          }
          uiDomString = F("<div class=\"slider\"><div class=\"sliderwrap il\"><input class=\"noslide\" onchange=\"requestJson({");
          uiDomString += FPSTR(_name);
          uiDomString += F(":{");
          uiDomString += FPSTR(_inputLvl);
          uiDomString += F(":parseInt(this.value)}});\" oninput=\"updateTrail(this);\" max=255 min=0 type=\"range\" value=");
          uiDomString += inputLevel;
          uiDomString += F(" /><div class=\"sliderdisplay\"></div></div></div>"); //<output class=\"sliderbubble\"></output>
          infoArr.add(uiDomString);
        } 
#endif
        // The following can be used for troubleshooting user errors and is so not enclosed in #ifdef WLED_DEBUG
        // current Audio input
        infoArr = user.createNestedArray(F("Audio Source"));
        if ((audioSyncEnabled == AUDIOSYNC_REC) || (!audioSyncIDLE && (audioSyncEnabled == AUDIOSYNC_REC_PLUS))){
          // UDP sound sync - receive mode
          infoArr.add(F("UDP sound sync"));
          if (udpSyncConnected) {
            if (millis() - last_UDPTime < AUDIOSYNC_IDLE_MS)
              infoArr.add(F(" - receiving"));
            else
              infoArr.add(F(" - idle"));
          } else {
            infoArr.add(F(" - no connection"));
          }
#ifndef ARDUINO_ARCH_ESP32  // substitute for 8266
        } else {
          infoArr.add(F("sound sync Off"));
        }
#else  // ESP32 only
        } else {
          // Analog or I2S digital input
          if (audioSource && (audioSource->isInitialized())) {
            // audio source successfully configured
            if (audioSource->getType() == AudioSource::Type_I2SAdc) {
              infoArr.add(F("ADC analog"));
            } else {
              if (dmType != 51)
                infoArr.add(F("I2S digital"));
              else
                infoArr.add(F("legacy I2S PDM"));
            }
            // input level or "silence"
            if (maxSample5sec > 1.0) {
              float my_usage = 100.0f * (maxSample5sec / 255.0f);
              snprintf_P(myStringBuffer, 15, PSTR(" - peak %3d%%"), int(my_usage));
              infoArr.add(myStringBuffer);
            } else {
              infoArr.add(F(" - quiet"));
            }
          } else {
            // error during audio source setup
            infoArr.add(F("not initialized"));
            infoArr.add(F(" - check pin settings"));
          }
        }

        // Sound processing (FFT and input filters)
        infoArr = user.createNestedArray(F("Sound Processing"));
        if (audioSource && (disableSoundProcessing == false)) {
          infoArr.add(F("running"));
        } else {
          infoArr.add(F("suspended"));
        }

        // AGC or manual Gain
        if ((soundAgc == 0) && (disableSoundProcessing == false) && !(audioSyncEnabled == AUDIOSYNC_REC)) {
          infoArr = user.createNestedArray(F("Manual Gain"));
          float myGain = ((float)sampleGain/40.0f * (float)inputLevel/128.0f) + 1.0f/16.0f;     // non-AGC gain from presets
          infoArr.add(roundf(myGain*100.0f) / 100.0f);
          infoArr.add("x");
        }
        if ((soundAgc > 0) && (disableSoundProcessing == false) && !(audioSyncEnabled == AUDIOSYNC_REC)) {
          infoArr = user.createNestedArray(F("AGC Gain"));
          infoArr.add(roundf(multAgc*100.0f) / 100.0f);
          infoArr.add("x");
        }
#endif
        // UDP Sound Sync status
        infoArr = user.createNestedArray(F("UDP Sound Sync"));
        if (audioSyncEnabled) {
          if (audioSyncEnabled & AUDIOSYNC_SEND) {
            infoArr.add(F("send mode"));
            if ((udpSyncConnected) && (millis() - lastTime < AUDIOSYNC_IDLE_MS)) infoArr.add(F(" v2+"));
          } else if (audioSyncEnabled == AUDIOSYNC_REC) {
              infoArr.add(F("receive mode"));
          } else if (audioSyncEnabled == AUDIOSYNC_REC_PLUS) {
              infoArr.add(F("receive+local mode"));
          }
        } else
          infoArr.add("off");
        if (audioSyncEnabled && !udpSyncConnected) infoArr.add(" <i>(unconnected)</i>");
        if (audioSyncEnabled && udpSyncConnected && (millis() - last_UDPTime < AUDIOSYNC_IDLE_MS)) {
            if (receivedFormat == 1) infoArr.add(F(" v1"));
            if (receivedFormat == 2) infoArr.add(F(" v2"));
            if (receivedFormat == 3) {
              if (audioSyncSequence) infoArr.add(F(" v2+")); // Sequence checking enabled
              else infoArr.add(F(" v2"));
            }
        }

        #if defined(WLED_DEBUG) || defined(SR_DEBUG) || defined(SR_STATS)
        #ifdef ARDUINO_ARCH_ESP32
        infoArr = user.createNestedArray(F("I2S cycle time"));
        infoArr.add(roundf(fftTaskCycle)/100.0f);
        infoArr.add(" ms");

        infoArr = user.createNestedArray(F("Sampling time"));
        infoArr.add(roundf(sampleTime)/100.0f);
        infoArr.add(" ms");

        infoArr = user.createNestedArray(F("FFT time"));
        infoArr.add(roundf(fftTime)/100.0f);
        if ((fftTime/100) >= FFT_MIN_CYCLE) // FFT time over budget -> I2S buffer will overflow 
          infoArr.add("<b style=\"color:red;\">! ms</b>");
        else if ((fftTime/80 + sampleTime/80) >= FFT_MIN_CYCLE) // FFT time >75% of budget -> risk of instability
          infoArr.add("<b style=\"color:orange;\"> ms!</b>");
        else
          infoArr.add(" ms");

        DEBUGSR_PRINTF("AR I2S cycle time: %5.2f ms\n", roundf(fftTaskCycle)/100.0f);
        DEBUGSR_PRINTF("AR Sampling time : %5.2f ms\n", roundf(sampleTime)/100.0f);
        DEBUGSR_PRINTF("AR FFT time      : %5.2f ms\n", roundf(fftTime)/100.0f);
        #endif
        #endif
      }
    }


    /*
     * addToJsonState() can be used to add custom entries to the /json/state part of the JSON API (state object).
     * Values in the state object may be modified by connected clients
     */
    void addToJsonState(JsonObject& root)
    {
      if (!initDone) return;  // prevent crash on boot applyPreset()
      JsonObject usermod = root[FPSTR(_name)];
      if (usermod.isNull()) {
        usermod = root.createNestedObject(FPSTR(_name));
      }
      usermod["on"] = enabled;
    }


    /*
     * readFromJsonState() can be used to receive data clients send to the /json/state part of the JSON API (state object).
     * Values in the state object may be modified by connected clients
     */
    void readFromJsonState(JsonObject& root)
    {
      if (!initDone) return;  // prevent crash on boot applyPreset()
      bool prevEnabled = enabled;
      JsonObject usermod = root[FPSTR(_name)];
      if (!usermod.isNull()) {
        if (usermod[FPSTR(_enabled)].is<bool>()) {
          enabled = usermod[FPSTR(_enabled)].as<bool>();
          if (prevEnabled != enabled) onUpdateBegin(!enabled);
        }
#ifdef ARDUINO_ARCH_ESP32
        if (usermod[FPSTR(_inputLvl)].is<int>()) {
          inputLevel = min(255,max(0,usermod[FPSTR(_inputLvl)].as<int>()));
        }
#endif
      }
    }


    /*
     * addToConfig() can be used to add custom persistent settings to the cfg.json file in the "um" (usermod) object.
     * It will be called by WLED when settings are actually saved (for example, LED settings are saved)
     * If you want to force saving the current state, use serializeConfig() in your loop().
     * 
     * CAUTION: serializeConfig() will initiate a filesystem write operation.
     * It might cause the LEDs to stutter and will cause flash wear if called too often.
     * Use it sparingly and always in the loop, never in network callbacks!
     * 
     * addToConfig() will make your settings editable through the Usermod Settings page automatically.
     *
     * Usermod Settings Overview:
     * - Numeric values are treated as floats in the browser.
     *   - If the numeric value entered into the browser contains a decimal point, it will be parsed as a C float
     *     before being returned to the Usermod.  The float data type has only 6-7 decimal digits of precision, and
     *     doubles are not supported, numbers will be rounded to the nearest float value when being parsed.
     *     The range accepted by the input field is +/- 1.175494351e-38 to +/- 3.402823466e+38.
     *   - If the numeric value entered into the browser doesn't contain a decimal point, it will be parsed as a
     *     C int32_t (range: -2147483648 to 2147483647) before being returned to the usermod.
     *     Overflows or underflows are truncated to the max/min value for an int32_t, and again truncated to the type
     *     used in the Usermod when reading the value from ArduinoJson.
     * - Pin values can be treated differently from an integer value by using the key name "pin"
     *   - "pin" can contain a single or array of integer values
     *   - On the Usermod Settings page there is simple checking for pin conflicts and warnings for special pins
     *     - Red color indicates a conflict.  Yellow color indicates a pin with a warning (e.g. an input-only pin)
     *   - Tip: use int8_t to store the pin value in the Usermod, so a -1 value (pin not set) can be used
     *
     * See usermod_v2_auto_save.h for an example that saves Flash space by reusing ArduinoJson key name strings
     * 
     * If you need a dedicated settings page with custom layout for your Usermod, that takes a lot more work.  
     * You will have to add the setting to the HTML, xml.cpp and set.cpp manually.
     * See the WLED Soundreactive fork (code and wiki) for reference.  https://github.com/atuline/WLED
     * 
     * I highly recommend checking out the basics of ArduinoJson serialization and deserialization in order to use custom settings!
     */
    void addToConfig(JsonObject& root)
    {
      JsonObject top = root.createNestedObject(FPSTR(_name));
      top[FPSTR(_enabled)] = enabled;
#ifdef ARDUINO_ARCH_ESP32
    #if !defined(CONFIG_IDF_TARGET_ESP32S2) && !defined(CONFIG_IDF_TARGET_ESP32C3) && !defined(CONFIG_IDF_TARGET_ESP32S3)
      JsonObject amic = top.createNestedObject(FPSTR(_analogmic));
      amic["pin"] = audioPin;
    #endif

      JsonObject dmic = top.createNestedObject(FPSTR(_digitalmic));
      dmic[F("type")] = dmType;
      // WLEDMM: align with globals I2C pins
      if ((dmType == 2) || (dmType == 6)) {         // only for ES7243 and ES8388
        if (i2c_sda >= 0) sdaPin = -1;              // -1 = use global
        if (i2c_scl >= 0) sclPin = -1;              // -1 = use global
      }
      JsonArray pinArray = dmic.createNestedArray("pin");
      pinArray.add(i2ssdPin);
      pinArray.add(i2swsPin);
      pinArray.add(i2sckPin);
      pinArray.add(mclkPin);
      pinArray.add(sdaPin);
      pinArray.add(sclPin);

      JsonObject cfg = top.createNestedObject("config");
      cfg[F("squelch")] = soundSquelch;
      cfg[F("gain")] = sampleGain;
      cfg[F("AGC")] = soundAgc;

      //WLEDMM: experimental settings
      JsonObject poweruser = top.createNestedObject("experiments");
      poweruser[F("micLev")] = micLevelMethod;
      poweruser[F("freqDist")] = freqDist;
      poweruser[F("freqRMS")] = averageByRMS;

      JsonObject freqScale = top.createNestedObject("frequency");
      freqScale[F("scale")] = FFTScalingMode;
      freqScale[F("profile")] = pinkIndex; //WLEDMM
#endif
      JsonObject dynLim = top.createNestedObject("dynamics");
      dynLim[F("limiter")] = limiterOn;
      dynLim[F("rise")] = attackTime;
      dynLim[F("fall")] = decayTime;

      JsonObject sync = top.createNestedObject("sync");
      sync[F("port")] = audioSyncPort;
      sync[F("mode")] = audioSyncEnabled;
      sync[F("check_sequence")] = audioSyncSequence;
    }


    /*
     * readFromConfig() can be used to read back the custom settings you added with addToConfig().
     * This is called by WLED when settings are loaded (currently this only happens immediately after boot, or after saving on the Usermod Settings page)
     * 
     * readFromConfig() is called BEFORE setup(). This means you can use your persistent values in setup() (e.g. pin assignments, buffer sizes),
     * but also that if you want to write persistent values to a dynamic buffer, you'd need to allocate it here instead of in setup.
     * If you don't know what that is, don't fret. It most likely doesn't affect your use case :)
     * 
     * Return true in case the config values returned from Usermod Settings were complete, or false if you'd like WLED to save your defaults to disk (so any missing values are editable in Usermod Settings)
     * 
     * getJsonValue() returns false if the value is missing, or copies the value into the variable provided and returns true if the value is present
     * The configComplete variable is true only if the "exampleUsermod" object and all values are present.  If any values are missing, WLED will know to call addToConfig() to save them
     * 
     * This function is guaranteed to be called on boot, but could also be called every time settings are updated
     */
    bool readFromConfig(JsonObject& root)
    {
      JsonObject top = root[FPSTR(_name)];
      bool configComplete = !top.isNull();

      configComplete &= getJsonValue(top[FPSTR(_enabled)], enabled);
#ifdef ARDUINO_ARCH_ESP32
    #if !defined(CONFIG_IDF_TARGET_ESP32S2) && !defined(CONFIG_IDF_TARGET_ESP32C3) && !defined(CONFIG_IDF_TARGET_ESP32S3)
      configComplete &= getJsonValue(top[FPSTR(_analogmic)]["pin"], audioPin);
    #else
      audioPin = -1; // MCU does not support analog mic
    #endif

      configComplete &= getJsonValue(top[FPSTR(_digitalmic)]["type"],   dmType);
    #if  defined(CONFIG_IDF_TARGET_ESP32S2) || defined(CONFIG_IDF_TARGET_ESP32C3) || defined(CONFIG_IDF_TARGET_ESP32S3)
      if (dmType == 0) dmType = SR_DMTYPE;   // MCU does not support analog
      #if defined(CONFIG_IDF_TARGET_ESP32S2) || defined(CONFIG_IDF_TARGET_ESP32C3)
      if (dmType == 5) dmType = SR_DMTYPE;   // MCU does not support PDM
      if (dmType == 51) dmType = SR_DMTYPE;  // MCU does not support legacy PDM
      #endif
    #else
      if (dmType == 5) useInputFilter = 1;      // enable filter for PDM
      if (dmType == 51) useInputFilter = 1;     // switch on filter for legacy PDM    
    #endif

      configComplete &= getJsonValue(top[FPSTR(_digitalmic)]["pin"][0], i2ssdPin);
      configComplete &= getJsonValue(top[FPSTR(_digitalmic)]["pin"][1], i2swsPin);
      configComplete &= getJsonValue(top[FPSTR(_digitalmic)]["pin"][2], i2sckPin);
      configComplete &= getJsonValue(top[FPSTR(_digitalmic)]["pin"][3], mclkPin);
      configComplete &= getJsonValue(top[FPSTR(_digitalmic)]["pin"][4], sdaPin);
      configComplete &= getJsonValue(top[FPSTR(_digitalmic)]["pin"][5], sclPin);

      configComplete &= getJsonValue(top["config"][F("squelch")], soundSquelch);
      configComplete &= getJsonValue(top["config"][F("gain")],    sampleGain);
      configComplete &= getJsonValue(top["config"][F("AGC")],     soundAgc);

      //WLEDMM: experimental settings
      configComplete &= getJsonValue(top["experiments"][F("micLev")], micLevelMethod);
      configComplete &= getJsonValue(top["experiments"][F("freqDist")], freqDist);
      configComplete &= getJsonValue(top["experiments"][F("freqRMS")],  averageByRMS);

      configComplete &= getJsonValue(top["frequency"][F("scale")], FFTScalingMode);
      configComplete &= getJsonValue(top["frequency"][F("profile")], pinkIndex);  //WLEDMM
#endif
      configComplete &= getJsonValue(top["dynamics"][F("limiter")], limiterOn);
      configComplete &= getJsonValue(top["dynamics"][F("rise")],  attackTime);
      configComplete &= getJsonValue(top["dynamics"][F("fall")],  decayTime);

      configComplete &= getJsonValue(top["sync"][F("port")], audioSyncPort);
      configComplete &= getJsonValue(top["sync"][F("mode")], audioSyncEnabled);
      configComplete &= getJsonValue(top["sync"][F("check_sequence")], audioSyncSequence);

      return configComplete;
    }


    void appendConfigData()
    {
      oappend(SET_F("addInfo('AudioReactive:help',0,'<button onclick=\"location.href=&quot;https://mm.kno.wled.ge/soundreactive/Sound-Settings&quot;\" type=\"button\">?</button>');"));
#ifdef ARDUINO_ARCH_ESP32      
      //WLEDMM: add defaults
      #if !defined(CONFIG_IDF_TARGET_ESP32S2) && !defined(CONFIG_IDF_TARGET_ESP32C3) && !defined(CONFIG_IDF_TARGET_ESP32S3)  // -S3/-S2/-C3 don't support analog audio
      #ifdef AUDIOPIN
        oappend(SET_F("xOpt('AudioReactive:analogmic:pin',1,' ⎌',")); oappendi(AUDIOPIN); oappend(");"); 
      #endif
      oappend(SET_F("aOpt('AudioReactive:analogmic:pin',1);")); //only analog options
      #endif

      oappend(SET_F("dd=addDropdown('AudioReactive','digitalmic:type');"));
      #if !defined(CONFIG_IDF_TARGET_ESP32S2) && !defined(CONFIG_IDF_TARGET_ESP32C3) && !defined(CONFIG_IDF_TARGET_ESP32S3)
        #if SR_DMTYPE==0
          oappend(SET_F("addOption(dd,'Generic Analog (⎌)',0);"));
        #else
          oappend(SET_F("addOption(dd,'Generic Analog',0);"));
        #endif
      #endif
      #if SR_DMTYPE==1
        oappend(SET_F("addOption(dd,'Generic I2S (⎌)',1);"));
      #else
        oappend(SET_F("addOption(dd,'Generic I2S',1);"));
      #endif
      #if SR_DMTYPE==2
        oappend(SET_F("addOption(dd,'ES7243 (⎌)',2);"));
      #else
        oappend(SET_F("addOption(dd,'ES7243',2);"));
      #endif
      #if SR_DMTYPE==3
        oappend(SET_F("addOption(dd,'SPH0654 (⎌)',3);"));
      #else
        oappend(SET_F("addOption(dd,'SPH0654',3);"));
      #endif
      #if SR_DMTYPE==4
        oappend(SET_F("addOption(dd,'Generic I2S with Mclk (⎌)',4);"));
      #else
        oappend(SET_F("addOption(dd,'Generic I2S with Mclk',4);"));
      #endif
      #if !defined(CONFIG_IDF_TARGET_ESP32S2) && !defined(CONFIG_IDF_TARGET_ESP32C3)
        #if SR_DMTYPE==5
          oappend(SET_F("addOption(dd,'Generic I2S PDM (⎌)',5);"));
        #else
          oappend(SET_F("addOption(dd,'Generic I2S PDM',5);"));
        #endif
        #if SR_DMTYPE==51
          oappend(SET_F("addOption(dd,'.Legacy I2S PDM ☾ (⎌)',51);"));
        #else
          oappend(SET_F("addOption(dd,'.Legacy I2S PDM ☾',51);"));
        #endif
      #endif
      #if SR_DMTYPE==6
        oappend(SET_F("addOption(dd,'ES8388 ☾ (⎌)',6);"));
      #else
        oappend(SET_F("addOption(dd,'ES8388 ☾',6);"));
      #endif
      #if SR_DMTYPE==7
        oappend(SET_F("addOption(dd,'WM8978 ☾ (⎌)',7);"));
      #else
        oappend(SET_F("addOption(dd,'WM8978 ☾',7);"));
      #endif
      #ifdef SR_SQUELCH
        oappend(SET_F("addInfo('AudioReactive:config:squelch',1,'<i>&#9100; ")); oappendi(SR_SQUELCH); oappend("</i>');");  // 0 is field type, 1 is actual field
      #endif
      #ifdef SR_GAIN
        oappend(SET_F("addInfo('AudioReactive:config:gain',1,'<i>&#9100; ")); oappendi(SR_GAIN); oappend("</i>');");  // 0 is field type, 1 is actual field
      #endif

      oappend(SET_F("dd=addDropdown('AudioReactive','config:AGC');"));
      oappend(SET_F("addOption(dd,'Off',0);"));
      oappend(SET_F("addOption(dd,'Normal',1);"));
      oappend(SET_F("addOption(dd,'Vivid',2);"));
      oappend(SET_F("addOption(dd,'Lazy',3);"));

      //WLEDMM: experimental settings
      oappend(SET_F("dd=addDropdown('AudioReactive','experiments:micLev');"));
      oappend(SET_F("addOption(dd,'Floating  (⎌)',0);"));
      oappend(SET_F("addOption(dd,'Freeze',1);"));
      oappend(SET_F("addOption(dd,'Fast Freeze',2);"));
      oappend(SET_F("addInfo('AudioReactive:experiments:micLev',1,'☾');"));

      oappend(SET_F("dd=addDropdown('AudioReactive','experiments:freqDist');"));
      oappend(SET_F("addOption(dd,'Normal  (⎌)',0);"));
      oappend(SET_F("addOption(dd,'RightShift',1);"));
      oappend(SET_F("addInfo('AudioReactive:experiments:freqDist',1,'☾');"));

      oappend(SET_F("dd=addDropdown('AudioReactive','experiments:freqRMS');"));
      oappend(SET_F("addOption(dd,'Off  (⎌)',0);"));
      oappend(SET_F("addOption(dd,'On',1);"));
      oappend(SET_F("addInfo('AudioReactive:experiments:freqRMS',1,'☾');"));

      oappend(SET_F("dd=addDropdown('AudioReactive','dynamics:limiter');"));
      oappend(SET_F("addOption(dd,'Off',0);"));
      oappend(SET_F("addOption(dd,'On',1);"));
      oappend(SET_F("addInfo('AudioReactive:dynamics:limiter',0,' On ');"));  // 0 is field type, 1 is actual field
      oappend(SET_F("addInfo('AudioReactive:dynamics:rise',1,'ms <i>(&#x266A; effects only)</i>');"));
      oappend(SET_F("addInfo('AudioReactive:dynamics:fall',1,'ms <i>(&#x266A; effects only)</i>');"));

      oappend(SET_F("dd=addDropdown('AudioReactive','frequency:scale');"));
      oappend(SET_F("addOption(dd,'None',0);"));
      oappend(SET_F("addOption(dd,'Linear (Amplitude)',2);"));
      oappend(SET_F("addOption(dd,'Square Root (Energy)',3);"));
      oappend(SET_F("addOption(dd,'Logarithmic (Loudness)',1);"));

      //WLEDMM add defaults
      oappend(SET_F("dd=addDropdown('AudioReactive','frequency:profile');"));
      #if SR_FREQ_PROF==0
        oappend(SET_F("addOption(dd,'Generic Microphone (⎌)',0);"));
      #else
        oappend(SET_F("addOption(dd,'Generic Microphone',0);"));
      #endif
      #if SR_FREQ_PROF==1
        oappend(SET_F("addOption(dd,'Generic Line-In (⎌)',1);"));
      #else
        oappend(SET_F("addOption(dd,'Generic Line-In',1);"));
      #endif
      #if SR_FREQ_PROF==5
        oappend(SET_F("addOption(dd,'ICS-43434 (⎌)',5);"));
      #else
        oappend(SET_F("addOption(dd,'ICS-43434',5);"));
      #endif
      #if SR_FREQ_PROF==6
        oappend(SET_F("addOption(dd,'ICS-43434 - big speakers (⎌)',6);"));
      #else
        oappend(SET_F("addOption(dd,'ICS-43434 - big speakers',6);"));
      #endif
      #if SR_FREQ_PROF==7
        oappend(SET_F("addOption(dd,'SPM1423 (⎌)',7);"));
      #else
        oappend(SET_F("addOption(dd,'SPM1423',7);"));
      #endif
      #if SR_FREQ_PROF==2
        oappend(SET_F("addOption(dd,'IMNP441 (⎌)',2);"));
      #else
        oappend(SET_F("addOption(dd,'IMNP441',2);"));
      #endif
      #if SR_FREQ_PROF==3
        oappend(SET_F("addOption(dd,'IMNP441 - big speakers (⎌)',3);"));
      #else
        oappend(SET_F("addOption(dd,'IMNP441 - big speakers',3);"));
      #endif
      #if SR_FREQ_PROF==4
        oappend(SET_F("addOption(dd,'IMNP441 - small speakers (⎌)',4);"));
      #else
        oappend(SET_F("addOption(dd,'IMNP441 - small speakers',4);"));
      #endif
      #if SR_FREQ_PROF==10
        oappend(SET_F("addOption(dd,'flat - no adjustments (⎌)',10);"));
      #else
        oappend(SET_F("addOption(dd,'flat - no adjustments',10);"));
      #endif
      #if SR_FREQ_PROF==8
        oappend(SET_F("addOption(dd,'userdefined #1 (⎌)',8);"));
      #else
        oappend(SET_F("addOption(dd,'userdefined #1',8);"));
      #endif
      #if SR_FREQ_PROF==9
        oappend(SET_F("addOption(dd,'userdefined #2 (⎌)',9);"));
      #else
        oappend(SET_F("addOption(dd,'userdefined #2',9);"));
      #endif
      oappend(SET_F("addInfo('AudioReactive:frequency:profile',1,'☾');"));
#endif
      oappend(SET_F("dd=addDropdown('AudioReactive','sync:mode');"));
      oappend(SET_F("addOption(dd,'Off',0);"));               // AUDIOSYNC_NONE
#ifdef ARDUINO_ARCH_ESP32
      oappend(SET_F("addOption(dd,'Send',1);"));              // AUDIOSYNC_SEND
#endif
      oappend(SET_F("addOption(dd,'Receive',2);"));           // AUDIOSYNC_REC
#ifdef ARDUINO_ARCH_ESP32
      oappend(SET_F("addOption(dd,'Receive or Local',6);"));  // AUDIOSYNC_REC_PLUS
#endif
      // check_sequence: Receiver skips out-of-sequence packets when enabled
      oappend(SET_F("dd=addDropdown('AudioReactive','sync:check_sequence');"));
      oappend(SET_F("addOption(dd,'Off',0);"));
      oappend(SET_F("addOption(dd,'On',1);"));

      oappend(SET_F("addInfo('AudioReactive:sync:check_sequence',1,'<i>when receiving</i> ☾<br> Sync audio data with other WLEDs');"));  // must append this to the last field of 'sync'

      oappend(SET_F("addInfo('AudioReactive:digitalmic:type',1,'<i>requires reboot!</i>');"));  // 0 is field type, 1 is actual field
#ifdef ARDUINO_ARCH_ESP32
      oappend(SET_F("addInfo('AudioReactive:digitalmic:pin[]',0,'<i>sd/data/dout</i>','I2S SD');"));
      #ifdef I2S_SDPIN
        oappend(SET_F("xOpt('AudioReactive:digitalmic:pin[]',0,' ⎌',")); oappendi(I2S_SDPIN); oappend(");"); 
      #endif

      oappend(SET_F("addInfo('AudioReactive:digitalmic:pin[]',1,'<i>ws/clk/lrck</i>','I2S WS');"));
      oappend(SET_F("dRO('AudioReactive:digitalmic:pin[]',1);")); // disable read only pins
      #ifdef I2S_WSPIN
        oappend(SET_F("xOpt('AudioReactive:digitalmic:pin[]',1,' ⎌',")); oappendi(I2S_WSPIN); oappend(");"); 
      #endif

      oappend(SET_F("addInfo('AudioReactive:digitalmic:pin[]',2,'<i>sck/bclk</i>','I2S SCK');"));
      oappend(SET_F("dRO('AudioReactive:digitalmic:pin[]',2);")); // disable read only pins
      #ifdef I2S_CKPIN
        oappend(SET_F("xOpt('AudioReactive:digitalmic:pin[]',2,' ⎌',")); oappendi(I2S_CKPIN); oappend(");"); 
      #endif

      oappend(SET_F("addInfo('AudioReactive:digitalmic:pin[]',3,'<i>master clock</i>','I2S MCLK');"));
      oappend(SET_F("dRO('AudioReactive:digitalmic:pin[]',3);")); // disable read only pins
      #if !defined(CONFIG_IDF_TARGET_ESP32S2) && !defined(CONFIG_IDF_TARGET_ESP32C3) && !defined(CONFIG_IDF_TARGET_ESP32S3)
        oappend(SET_F("dOpt('AudioReactive:digitalmic:pin[]',3,2,2);")); //only use -1, 0, 1 or 3
        oappend(SET_F("dOpt('AudioReactive:digitalmic:pin[]',3,4,39);")); //only use -1, 0, 1 or 3
      #endif
      #ifdef MCLK_PIN
        oappend(SET_F("xOpt('AudioReactive:digitalmic:pin[]',3,' ⎌',")); oappendi(MCLK_PIN); oappend(");"); 
      #endif

      oappend(SET_F("addInfo('AudioReactive:digitalmic:pin[]',4,'','I2C SDA');"));
      oappend(SET_F("rOpt('AudioReactive:digitalmic:pin[]',4,'use global (")); oappendi(i2c_sda); oappend(")',-1);"); 
      #ifdef ES7243_SDAPIN
        oappend(SET_F("xOpt('AudioReactive:digitalmic:pin[]',4,' ⎌',")); oappendi(ES7243_SDAPIN); oappend(");"); 
      #endif

      oappend(SET_F("addInfo('AudioReactive:digitalmic:pin[]',5,'','I2C SCL');"));
      oappend(SET_F("rOpt('AudioReactive:digitalmic:pin[]',5,'use global (")); oappendi(i2c_scl); oappend(")',-1);"); 
      #ifdef ES7243_SCLPIN
        oappend(SET_F("xOpt('AudioReactive:digitalmic:pin[]',5,' ⎌',")); oappendi(ES7243_SCLPIN); oappend(");"); 
      #endif
      oappend(SET_F("dRO('AudioReactive:digitalmic:pin[]',5);")); // disable read only pins
#endif
    }


    /*
     * handleOverlayDraw() is called just before every show() (LED strip update frame) after effects have set the colors.
     * Use this to blank out some LEDs or set them to a different color regardless of the set effect mode.
     * Commonly used for custom clocks (Cronixie, 7 segment)
     */
    //void handleOverlayDraw()
    //{
      //strip.setPixelColor(0, RGBW32(0,0,0,0)) // set the first pixel to black
    //}

   
    /*
     * getId() allows you to optionally give your V2 usermod an unique ID (please define it in const.h!).
     * This could be used in the future for the system to determine whether your usermod is installed.
     */
    uint16_t getId()
    {
      return USERMOD_ID_AUDIOREACTIVE;
    }
};

// strings to reduce flash memory usage (used more than twice)
const char AudioReactive::_name[]       PROGMEM = "AudioReactive";
const char AudioReactive::_enabled[]    PROGMEM = "enabled";
const char AudioReactive::_inputLvl[]   PROGMEM = "inputLevel";
#if defined(ARDUINO_ARCH_ESP32) && !defined(CONFIG_IDF_TARGET_ESP32S2) && !defined(CONFIG_IDF_TARGET_ESP32C3) && !defined(CONFIG_IDF_TARGET_ESP32S3)
const char AudioReactive::_analogmic[]  PROGMEM = "analogmic";
#endif
const char AudioReactive::_digitalmic[] PROGMEM = "digitalmic";
const char AudioReactive::UDP_SYNC_HEADER[]    PROGMEM = "00002"; // new sync header version, as format no longer compatible with previous structure
const char AudioReactive::UDP_SYNC_HEADER_v1[] PROGMEM = "00001"; // old sync header version - need to add backwards-compatibility feature