adaptive_digital_gain_controller.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/adaptive_digital_gain_controller.h"

#include <algorithm>

#include "common_audio/include/audio_util.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/logging.h"
#include "rtc_base/numerics/safe_minmax.h"
#include "system_wrappers/include/metrics.h"

namespace webrtc {
namespace {

AdaptiveDigitalConfig;

constexpr int kHeadroomHistogramMin = …;
constexpr int kHeadroomHistogramMax = …;
constexpr int kGainDbHistogramMax = …;

// Computes the gain for `input_level_dbfs` to reach `-config.headroom_db`.
// Clamps the gain in [0, `config.max_gain_db`]. `config.headroom_db` is a
// safety margin to allow transient peaks to exceed the target peak level
// without clipping.
float ComputeGainDb(float input_level_dbfs,
                    const AdaptiveDigitalConfig& config) { … }

// Returns `target_gain_db` if applying such a gain to `input_noise_level_dbfs`
// does not exceed `max_output_noise_level_dbfs`. Otherwise lowers and returns
// `target_gain_db` so that the output noise level equals
// `max_output_noise_level_dbfs`.
float LimitGainByNoise(float target_gain_db,
                       float input_noise_level_dbfs,
                       float max_output_noise_level_dbfs,
                       ApmDataDumper& apm_data_dumper) { … }

float LimitGainByLowConfidence(float target_gain_db,
                               float last_gain_db,
                               float limiter_audio_level_dbfs,
                               bool estimate_is_confident) { … }

// Computes how the gain should change during this frame.
// Return the gain difference in db to 'last_gain_db'.
float ComputeGainChangeThisFrameDb(float target_gain_db,
                                   float last_gain_db,
                                   bool gain_increase_allowed,
                                   float max_gain_decrease_db,
                                   float max_gain_increase_db) { … }

}  // namespace

AdaptiveDigitalGainController::AdaptiveDigitalGainController(
    ApmDataDumper* apm_data_dumper,
    const AudioProcessing::Config::GainController2::AdaptiveDigital& config,
    int adjacent_speech_frames_threshold)
    : … { … }

void AdaptiveDigitalGainController::Process(const FrameInfo& info,
                                            DeinterleavedView<float> frame) { … }

}  // namespace webrtc
chromium/third_party/webrtc/modules/audio_processing/agc2/adaptive_digital_gain_controller.cc
