Function GetPeriodicHann

tensorflow/lite/kernels/internal/spectrogram.cc:30–37

Returns the default Hann window function for the spectrogram.

namespace {
// Returns the default Hann window function for the spectrogram.
void GetPeriodicHann(int window_length, std::vector<double>* window) {
  // Some platforms don't have M_PI, so define a local constant here.
  const double pi = std::atan(1.0) * 4.0;
  window->resize(window_length);
  for (int i = 0; i < window_length; ++i) {
    (*window)[i] = 0.5 - 0.5 * cos((2.0 * pi * i) / window_length);
  }
}
}  // namespace

bool Spectrogram::Initialize(int window_length, int step_length) {