chromium/third_party/webrtc/modules/audio_processing/agc2/rnn_vad/spectral_features_internal.cc

/*
 *  Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

#include "modules/audio_processing/agc2/rnn_vad/spectral_features_internal.h"

#include <algorithm>
#include <cmath>
#include <cstddef>

#include "rtc_base/checks.h"
#include "rtc_base/numerics/safe_compare.h"

namespace webrtc {
namespace rnn_vad {
namespace {

// Weights for each FFT coefficient for each Opus band (Nyquist frequency
// excluded). The size of each band is specified in
// `kOpusScaleNumBins24kHz20ms`.
constexpr std::array<float, kFrameSize20ms24kHz / 2> kOpusBandWeights24kHz20ms = …;

}  // namespace

SpectralCorrelator::SpectralCorrelator()
    : … { … }

SpectralCorrelator::~SpectralCorrelator() = default;

void SpectralCorrelator::ComputeAutoCorrelation(
    rtc::ArrayView<const float> x,
    rtc::ArrayView<float, kOpusBands24kHz> auto_corr) const { … }

void SpectralCorrelator::ComputeCrossCorrelation(
    rtc::ArrayView<const float> x,
    rtc::ArrayView<const float> y,
    rtc::ArrayView<float, kOpusBands24kHz> cross_corr) const { … }

void ComputeSmoothedLogMagnitudeSpectrum(
    rtc::ArrayView<const float> bands_energy,
    rtc::ArrayView<float, kNumBands> log_bands_energy) { … }

std::array<float, kNumBands * kNumBands> ComputeDctTable() { … }

void ComputeDct(rtc::ArrayView<const float> in,
                rtc::ArrayView<const float, kNumBands * kNumBands> dct_table,
                rtc::ArrayView<float> out) { … }

}  // namespace rnn_vad
}  // namespace webrtc