chromium/third_party/webrtc/modules/audio_processing/agc2/interpolated_gain_curve.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/interpolated_gain_curve.h"

#include <algorithm>
#include <iterator>

#include "absl/strings/string_view.h"
#include "modules/audio_processing/agc2/agc2_common.h"
#include "modules/audio_processing/logging/apm_data_dumper.h"
#include "rtc_base/checks.h"
#include "rtc_base/strings/string_builder.h"

namespace webrtc {

constexpr std::array<float, kInterpolatedGainCurveTotalPoints>
    InterpolatedGainCurve::approximation_params_x_;

constexpr std::array<float, kInterpolatedGainCurveTotalPoints>
    InterpolatedGainCurve::approximation_params_m_;

constexpr std::array<float, kInterpolatedGainCurveTotalPoints>
    InterpolatedGainCurve::approximation_params_q_;

InterpolatedGainCurve::InterpolatedGainCurve(
    ApmDataDumper* apm_data_dumper,
    absl::string_view histogram_name_prefix)
    : … { … }

InterpolatedGainCurve::~InterpolatedGainCurve() { … }

InterpolatedGainCurve::RegionLogger::RegionLogger(
    absl::string_view identity_histogram_name,
    absl::string_view knee_histogram_name,
    absl::string_view limiter_histogram_name,
    absl::string_view saturation_histogram_name)
    : … { … }

InterpolatedGainCurve::RegionLogger::~RegionLogger() = default;

void InterpolatedGainCurve::RegionLogger::LogRegionStats(
    const InterpolatedGainCurve::Stats& stats) const { … }

void InterpolatedGainCurve::UpdateStats(float input_level) const { … }

// Looks up a gain to apply given a non-negative input level.
// The cost of this operation depends on the region in which `input_level`
// falls.
// For the identity and the saturation regions the cost is O(1).
// For the other regions, namely knee and limiter, the cost is
// O(2 + log2(`LightkInterpolatedGainCurveTotalPoints`), plus O(1) for the
// linear interpolation (one product and one sum).
float InterpolatedGainCurve::LookUpGainToApply(float input_level) const { … }

}  // namespace webrtc