Signalsmith-Audio/signalsmith-stretch
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Formant metric based on peaks/dips

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Geraint 2025-08-10 16:59:13 +01:00
parent 53159860b1
commit 12de19e05d
1 changed files with 15 additions and 8 deletions
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23
signalsmith-stretch.h
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@ -965,20 +965,27 @@ private:
freqEstimate = freqToBand(formantBaseFreq); freqEstimate = freqToBand(formantBaseFreq);
if (formantBaseFreq <= 0) freqEstimate = estimateFrequency(); if (formantBaseFreq <= 0) freqEstimate = estimateFrequency();
for (int b = 0; b < bands; ++b) {
formantMetric[b] = std::sqrt(formantMetric[b]);
}
} else if (step-- == 0) { } else if (step-- == 0) {
Sample slew = 1/(freqEstimate*0.5 + 1); Sample decay = 1 - 1/(freqEstimate*0.5 + 1);
Sample e = 0; Sample e = 0;
for (size_t repeat = 0; repeat < 2; ++repeat) { for (size_t repeat = 0; repeat < 2; ++repeat) {
for (int b = bands - 1; b >= 0; --b) { for (int b = bands - 1; b >= 0; --b) {
e += (formantMetric[b] - e)*slew; e = std::max(formantMetric[b], e*decay);
formantMetric[b] = e; formantMetric[b] = e;
} }
for (int b = 0; b < bands; ++b) { for (int b = 0; b < bands; ++b) {
e += (formantMetric[b] - e)*slew; e = std::max(formantMetric[b], e*decay);
formantMetric[b] = e;
}
}
decay = 1/decay;
for (size_t repeat = 0; repeat < 2; ++repeat) {
for (int b = bands - 1; b >= 0; --b) {
e = std::min(formantMetric[b], e*decay);
formantMetric[b] = e;
}
for (int b = 0; b < bands; ++b) {
e = std::min(formantMetric[b], e*decay);
formantMetric[b] = e; formantMetric[b] = e;
} }
} }
@ -1001,7 +1008,7 @@ private:
Sample targetE = getFormant(freqToBand(outputF)); Sample targetE = getFormant(freqToBand(outputF));
Sample formantRatio = targetE/(inputE + Sample(1e-30)); Sample formantRatio = targetE/(inputE + Sample(1e-30));
Sample energyRatio = formantRatio*formantRatio; Sample energyRatio = formantRatio;
for (int c = 0; c < channels; ++c) { for (int c = 0; c < channels; ++c) {
Band *bins = bandsForChannel(c); Band *bins = bandsForChannel(c);