chromium/third_party/webrtc/modules/audio_processing/agc2/clipping_predictor.cc

/*
 *  Copyright (c) 2021 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/clipping_predictor.h"

#include <algorithm>
#include <memory>

#include "common_audio/include/audio_util.h"
#include "modules/audio_processing/agc2/clipping_predictor_level_buffer.h"
#include "modules/audio_processing/agc2/gain_map_internal.h"
#include "rtc_base/checks.h"
#include "rtc_base/logging.h"
#include "rtc_base/numerics/safe_minmax.h"

namespace webrtc {
namespace {

constexpr int kClippingPredictorMaxGainChange = …;

// Returns an input volume in the [`min_input_volume`, `max_input_volume`] range
// that reduces `gain_error_db`, which is a gain error estimated when
// `input_volume` was applied, according to a fixed gain map.
int ComputeVolumeUpdate(int gain_error_db,
                        int input_volume,
                        int min_input_volume,
                        int max_input_volume) { … }

float ComputeCrestFactor(const ClippingPredictorLevelBuffer::Level& level) { … }

// Crest factor-based clipping prediction and clipped level step estimation.
class ClippingEventPredictor : public ClippingPredictor { … };

// Performs crest factor-based clipping peak prediction.
class ClippingPeakPredictor : public ClippingPredictor { … };

}  // namespace

std::unique_ptr<ClippingPredictor> CreateClippingPredictor(
    int num_channels,
    const AudioProcessing::Config::GainController1::AnalogGainController::
        ClippingPredictor& config) { … }

}  // namespace webrtc