Signalsmith-Audio/signalsmith-stretch
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Add .flush() for getting the final bits of output without any input

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Geraint 2024-02-19 10:20:40 +00:00
parent ebaf93d494
commit a9d78f0331
1 changed files with 34 additions and 2 deletions
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36
signalsmith-stretch.h
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@ -38,6 +38,7 @@ struct SignalsmithStretch {
channelBands.assign(channelBands.size(), Band());
silenceCounter = 2*stft.windowSize();
didSeek = false;
flushed = true;
}
// Configures using a default preset
@ -183,6 +184,7 @@ struct SignalsmithStretch {
}
stft.analyse(c, timeBuffer);
}
flushed = false; // TODO: first block after a flush should be gain-compensated
for (int c = 0; c < channels; ++c) {
auto channelBands = bandsForChannel(c);
@ -250,7 +252,37 @@ struct SignalsmithStretch {
stft += outputSamples;
prevInputOffset -= inputSamples;
}
// Read the remaining output, providing no further input. `outputSamples` should ideally be at least `.outputLatency()`
template<class Outputs>
void flush(Outputs &&outputs, int outputSamples) {
int plainOutput = std::min<int>(outputSamples, stft.windowSize());
int foldedBackOutput = std::min<int>(outputSamples, stft.windowSize() - plainOutput);
for (int c = 0; c < channels; ++c) {
auto &&outputChannel = outputs[c];
auto &&stftChannel = stft[c];
for (int i = 0; i < plainOutput; ++i) {
// TODO: plain output should be gain-
outputChannel[i] = stftChannel[i];
}
for (int i = 0; i < foldedBackOutput; ++i) {
outputChannel[outputSamples - 1 - i] -= stftChannel[plainOutput + i];
}
for (int i = 0; i < plainOutput + foldedBackOutput; ++i) {
stftChannel[i] = 0;
}
}
// Skip the output we just used/cleared
stft += plainOutput + foldedBackOutput;
// Reset the phase-vocoder stuff, so the next block gets a fresh start
for (int c = 0; c < channels; ++c) {
auto channelBands = bandsForChannel(c);
for (int b = 0; b < bands; ++b) {
channelBands[b].prevInput = channelBands[b].prevOutput = 0;
}
}
flushed = true;
}
private:
using Complex = std::complex<Sample>;
static constexpr Sample noiseFloor{1e-15};
@ -266,7 +298,7 @@ private:
int channels = 0, bands = 0;
int prevInputOffset = -1;
std::vector<Sample> timeBuffer;
bool didSeek = false;
bool didSeek = false, flushed = true;
Sample seekTimeFactor = 1;
std::vector<Complex> rotCentreSpectrum, rotPrevInterval;