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user-selectable FFT window functions

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experiments: user-selectable FFT "windowing" options

https://en.wikipedia.org/wiki/Window_function#Cosine-sum_windows
This commit is contained in:
Frank
2024-07-04 21:44:09 +02:00
parent 9b14de06b2
commit 160e66a766
1 changed files with 99 additions and 65 deletions
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164
usermods/audioreactive/audio_reactive.h
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@@ -179,7 +179,7 @@ static bool limiterOn = false; // bool: enable / disable dynamic
static bool limiterOn = true;
#endif
#ifdef FFT_USE_SLIDING_WINDOW
static uint16_t attackTime = 14; // int: attack time in milliseconds. Default 0.014sec
static uint16_t attackTime = 24; // int: attack time in milliseconds. Default 0.024sec
static uint16_t decayTime = 250; // int: decay time in milliseconds. New default 250ms.
#else
static uint16_t attackTime = 50; // int: attack time in milliseconds. Default 0.08sec
@@ -257,6 +257,7 @@ static constexpr uint8_t averageByRMS = false; // false: us
static constexpr 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
static uint8_t fftWindow = 0; // FFT windowing function (0 = default)
#ifdef FFT_USE_SLIDING_WINDOW
static uint8_t doSlidingFFT = 1; // 1 = use sliding window FFT (faster & more accurate)
#endif
@@ -685,17 +686,41 @@ void FFTcode(void * parameter)
micReal_max2 = datMax;
#endif
#endif
float wc = 1.0; // FFT window correction factor, relative to Blackman_Harris
// 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)
if (doDCRemoval) 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
switch(fftWindow) { // apply FFT window
case 1:
FFT.windowing(FFTWindow::Hann, FFTDirection::Forward); // recommended for 50% overlap
wc = 0.66415918066; // 1.8554726898 * 2.0
break;
case 2:
FFT.windowing( FFTWindow::Nuttall, FFTDirection::Forward);
wc = 0.9916873881f; // 2.8163172034 * 2.0
break;
case 3:
FFT.windowing( FFTWindow::Hamming, FFTDirection::Forward);
wc = 0.664159180663f; // 1.8549343278 * 2.0
break;
case 4:
FFT.windowing( FFTWindow::Flat_top, FFTDirection::Forward); // Weigh data using "Flat Top" function - better amplitude preservation, low frequency accuracy
wc = 1.276771793156f; // 3.5659039231 * 2.0
break;
case 0: // falls through
default:
FFT.windowing(FFTWindow::Blackman_Harris, FFTDirection::Forward); // Weigh data using "Blackman- Harris" window - sharp peaks due to excellent sideband rejection
wc = 1.0f; // 2.7929062517 * 2.0
}
#ifdef FFT_USE_SLIDING_WINDOW
if (usingOldSamples) wc = wc * 1.10f; // compensate for loss caused by averaging
#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.
@@ -715,6 +740,7 @@ void FFTcode(void * parameter)
#else
FFT.majorPeak(FFT_MajorPeak, FFT_Magnitude); // let the effects know which freq was most dominant
#endif
FFT_Magnitude *= wc; // apply correction factor
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
@@ -764,23 +790,23 @@ void FFTcode(void * parameter)
* 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
*/ // Range
fftCalc[ 0] = wc * fftAddAvg(2,4); // 60 - 100
fftCalc[ 1] = wc * fftAddAvg(4,5); // 80 - 120
fftCalc[ 2] = wc * fftAddAvg(5,7); // 100 - 160
fftCalc[ 3] = wc * fftAddAvg(7,9); // 140 - 200
fftCalc[ 4] = wc * fftAddAvg(9,12); // 180 - 260
fftCalc[ 5] = wc * fftAddAvg(12,16); // 240 - 340
fftCalc[ 6] = wc * fftAddAvg(16,21); // 320 - 440
fftCalc[ 7] = wc * fftAddAvg(21,29); // 420 - 600
fftCalc[ 8] = wc * fftAddAvg(29,37); // 580 - 760
fftCalc[ 9] = wc * fftAddAvg(37,48); // 740 - 980
fftCalc[10] = wc * fftAddAvg(48,64); // 960 - 1300
fftCalc[11] = wc * fftAddAvg(64,84); // 1280 - 1700
fftCalc[12] = wc * fftAddAvg(84,111); // 1680 - 2240
fftCalc[13] = wc * fftAddAvg(111,147); // 2220 - 2960
fftCalc[14] = wc * fftAddAvg(147,194); // 2940 - 3900
fftCalc[15] = wc * fftAddAvg(194,250); // 3880 - 5000 // avoid the last 5 bins, which are usually inaccurate
#else
//WLEDMM: different distributions
if (freqDist == 0) {
@@ -788,60 +814,60 @@ void FFTcode(void * parameter)
// 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);
fftCalc[ 0] = wc * 0.8f * fftAddAvg(3,3);
fftCalc[ 1] = wc * 0.9f * fftAddAvg(4,4);
fftCalc[ 2] = wc * fftAddAvg(5,5);
fftCalc[ 3] = wc * 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
fftCalc[15] = wc * 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
fftCalc[ 0] = wc * fftAddAvg(1,1); // 1 43 - 86 sub-bass
fftCalc[ 1] = wc * fftAddAvg(2,2); // 1 86 - 129 bass
fftCalc[ 2] = wc * fftAddAvg(3,4); // 2 129 - 216 bass
fftCalc[ 3] = wc * 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[15] = wc * 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
fftCalc[ 4] = wc * fftAddAvg(7,9); // 3 301 - 430 midrange
fftCalc[ 5] = wc * fftAddAvg(10,12); // 3 430 - 560 midrange
fftCalc[ 6] = wc * fftAddAvg(13,18); // 5 560 - 818 midrange
fftCalc[ 7] = wc * fftAddAvg(19,25); // 7 818 - 1120 midrange -- 1Khz should always be the center !
fftCalc[ 8] = wc * fftAddAvg(26,32); // 7 1120 - 1421 midrange
fftCalc[ 9] = wc * fftAddAvg(33,43); // 9 1421 - 1895 midrange
fftCalc[10] = wc * fftAddAvg(44,55); // 12 1895 - 2412 midrange + high mid
fftCalc[11] = wc * fftAddAvg(56,69); // 14 2412 - 3015 high mid
fftCalc[12] = wc * fftAddAvg(70,85); // 16 3015 - 3704 high mid
fftCalc[13] = wc * fftAddAvg(86,103); // 18 3704 - 4479 high mid
fftCalc[14] = wc * 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);
fftCalc[ 0] = wc * 0.8f * fftAddAvg(1,1);
fftCalc[ 1] = wc * 0.9f * fftAddAvg(2,2);
fftCalc[ 2] = wc * fftAddAvg(3,3);
fftCalc[ 3] = wc * 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
fftCalc[15] = wc * 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
fftCalc[ 0] = wc * fftAddAvg(1,1); // 1 43 - 86 sub-bass
fftCalc[ 1] = wc * fftAddAvg(2,2); // 1 86 - 129 bass
fftCalc[ 2] = wc * fftAddAvg(3,3); // 2 129 - 216 bass
fftCalc[ 3] = wc * 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[15] = wc * 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
fftCalc[ 4] = wc * fftAddAvg(5,6); // 3 301 - 430 midrange
fftCalc[ 5] = wc * fftAddAvg(7,8); // 3 430 - 560 midrange
fftCalc[ 6] = wc * fftAddAvg(9,10); // 5 560 - 818 midrange
fftCalc[ 7] = wc * fftAddAvg(11,13); // 7 818 - 1120 midrange -- 1Khz should always be the center !
fftCalc[ 8] = wc * fftAddAvg(14,18); // 7 1120 - 1421 midrange
fftCalc[ 9] = wc * fftAddAvg(19,25); // 9 1421 - 1895 midrange
fftCalc[10] = wc * fftAddAvg(26,36); // 12 1895 - 2412 midrange + high mid
fftCalc[11] = wc * fftAddAvg(37,45); // 14 2412 - 3015 high mid
fftCalc[12] = wc * fftAddAvg(46,66); // 16 3015 - 3704 high mid
fftCalc[13] = wc * fftAddAvg(67,97); // 18 3704 - 4479 high mid
fftCalc[14] = wc * fftAddAvg(98,164) * 0.88f; // 61 4479 - 7106 high mid + high -- with slight damping
}
#endif
} else { // noise gate closed - just decay old values
@@ -2756,7 +2782,7 @@ class AudioReactive : public Usermod {
poweruser[F("micLev")] = micLevelMethod;
poweruser[F("freqDist")] = freqDist;
//poweruser[F("freqRMS")] = averageByRMS;
poweruser[F("FFT_Window")] = fftWindow;
#ifdef FFT_USE_SLIDING_WINDOW
poweruser[F("I2S_FastPath")] = doSlidingFFT;
#endif
@@ -2831,6 +2857,7 @@ class AudioReactive : public Usermod {
configComplete &= getJsonValue(top["experiments"][F("micLev")], micLevelMethod);
configComplete &= getJsonValue(top["experiments"][F("freqDist")], freqDist);
//configComplete &= getJsonValue(top["experiments"][F("freqRMS")], averageByRMS);
configComplete &= getJsonValue(top["experiments"][F("FFT_Window")], fftWindow);
#ifdef FFT_USE_SLIDING_WINDOW
configComplete &= getJsonValue(top["experiments"][F("I2S_FastPath")], doSlidingFFT);
#endif
@@ -2944,6 +2971,13 @@ class AudioReactive : public Usermod {
//oappend(SET_F("addOption(dd,'On',1);"));
//oappend(SET_F("addInfo(ux+':experiments:freqRMS',1,'☾');"));
oappend(SET_F("dd=addDropdown(ux,'experiments:FFT_Window');"));
oappend(SET_F("addOption(dd,'Blackman-Harris (MM standard)',0);"));
oappend(SET_F("addOption(dd,'Hann (balanced)',1);"));
oappend(SET_F("addOption(dd,'Nuttall (more accurate)',2);"));
oappend(SET_F("addOption(dd,'Hamming',3);"));
oappend(SET_F("addOption(dd,'Flat-Top (AC WLED, inaccurate)',4);"));
#ifdef FFT_USE_SLIDING_WINDOW
oappend(SET_F("dd=addDropdown(ux,'experiments:I2S_FastPath');"));
oappend(SET_F("addOption(dd,'Off',0);"));