90 lines
2.7 KiB
C++
90 lines
2.7 KiB
C++
#include "spectral.hpp"
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#include <cmath>
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#include <cstring>
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#include <vector>
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SpectralProcessor::SpectralProcessor(size_t nfft, size_t hop, float sample_rate)
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: nfft_(nfft), hop_(hop), frame_count_(0), output_pos_(0),
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detector_(nfft, sample_rate) {
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window_ = new double[nfft_];
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computeWindow();
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fft::init_plan(&plan_, static_cast<uint32_t>(std::log2(nfft_)));
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buf_ = new std::complex<double>[nfft_];
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tmp_buf_ = new std::complex<double>[nfft_];
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overlap_.resize(nfft_, 0.0f);
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mask_.resize(nfft_, 1.0f);
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}
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SpectralProcessor::~SpectralProcessor() {
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delete[] window_;
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delete[] buf_;
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delete[] tmp_buf_;
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}
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void SpectralProcessor::setDetectorParams(const std::vector<DetectorBand>& bands) {
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detector_.setParams(bands);
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}
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void SpectralProcessor::computeWindow() {
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for (size_t i = 0; i < nfft_; i++) {
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window_[i] = 0.5 * (1.0 - std::cos(2.0 * M_PI * i / (nfft_ - 1)));
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}
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}
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void SpectralProcessor::stftFrame(const float* in, std::complex<double>* out) {
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for (size_t i = 0; i < nfft_; i++) {
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out[i] = std::complex<double>(static_cast<double>(in[i]) * window_[i], 0.0);
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}
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fft::execute(&plan_, out);
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}
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void SpectralProcessor::istftFrame(std::complex<double>* in, float* out, float* overlap) {
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memcpy(tmp_buf_, in, nfft_ * sizeof(std::complex<double>));
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fft::execute_inverse(&plan_, tmp_buf_);
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static bool wola_computed = false;
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static float wola_norm = 1.0f;
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if (!wola_computed) {
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double wola_sum = 0.0;
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for (size_t i = 0; i < nfft_; i++) {
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wola_sum += window_[i] * window_[i];
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}
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wola_norm = static_cast<float>(wola_sum / hop_);
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wola_computed = true;
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}
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for (size_t i = 0; i < nfft_; i++) {
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overlap[i] += static_cast<float>(tmp_buf_[i].real() * window_[i]);
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}
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for (size_t i = 0; i < hop_; i++) {
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out[i] = overlap[i] / wola_norm;
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}
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for (size_t i = 0; i < nfft_ - hop_; i++) {
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overlap[i] = overlap[i + hop_];
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}
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for (size_t i = nfft_ - hop_; i < nfft_; i++) {
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overlap[i] = 0.0f;
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}
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}
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void SpectralProcessor::processBlock(float* in, float* out, size_t num_samples, size_t num_channels) {
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memset(out, 0, num_samples * sizeof(float));
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if (num_samples == 0 || num_samples < nfft_) {
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return;
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}
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size_t nframes = (num_samples - nfft_) / hop_ + 1;
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for (size_t f = 0; f < nframes; f++) {
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size_t offset = f * hop_;
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if (offset + nfft_ > num_samples) break;
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stftFrame(in + offset, buf_);
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detector_.processFrame(buf_, mask_.data());
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for (size_t i = 0; i < nfft_; i++) {
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buf_[i] *= mask_[i];
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}
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istftFrame(buf_, out + offset, overlap_.data());
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}
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}
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