chromium/third_party/webrtc/modules/audio_processing/agc2/rnn_vad/lp_residual.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/lp_residual.h"

#include <algorithm>
#include <array>
#include <cmath>
#include <numeric>

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

namespace webrtc {
namespace rnn_vad {
namespace {

// Computes auto-correlation coefficients for `x` and writes them in
// `auto_corr`. The lag values are in {0, ..., max_lag - 1}, where max_lag
// equals the size of `auto_corr`.
void ComputeAutoCorrelation(
    rtc::ArrayView<const float> x,
    rtc::ArrayView<float, kNumLpcCoefficients> auto_corr) { … }

// Applies denoising to the auto-correlation coefficients.
void DenoiseAutoCorrelation(
    rtc::ArrayView<float, kNumLpcCoefficients> auto_corr) { … }

// Computes the initial inverse filter coefficients given the auto-correlation
// coefficients of an input frame.
void ComputeInitialInverseFilterCoefficients(
    rtc::ArrayView<const float, kNumLpcCoefficients> auto_corr,
    rtc::ArrayView<float, kNumLpcCoefficients - 1> lpc_coeffs) { … }

}  // namespace

void ComputeAndPostProcessLpcCoefficients(
    rtc::ArrayView<const float> x,
    rtc::ArrayView<float, kNumLpcCoefficients> lpc_coeffs) { … }

void ComputeLpResidual(
    rtc::ArrayView<const float, kNumLpcCoefficients> lpc_coeffs,
    rtc::ArrayView<const float> x,
    rtc::ArrayView<float> y) { … }

}  // namespace rnn_vad
}  // namespace webrtc