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/*
* 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.
*/
#ifndef MODULES_AUDIO_PROCESSING_AGC_CLIPPING_PREDICTOR_H_
#define MODULES_AUDIO_PROCESSING_AGC_CLIPPING_PREDICTOR_H_
#include <memory>
#include <vector>
#include "absl/types/optional.h"
#include "modules/audio_processing/include/audio_frame_view.h"
#include "modules/audio_processing/include/audio_processing.h"
namespace webrtc {
// Frame-wise clipping prediction and clipped level step estimation. Processing
// is done in two steps: Calling `Process` analyses a frame of audio and stores
// the frame metrics and `EstimateClippedLevelStep` produces an estimate for the
// required analog gain level decrease if clipping is predicted.
class ClippingPredictor {
public:
virtual ~ClippingPredictor() = default;
virtual void Reset() = 0;
// Estimates the analog gain clipped level step for channel `channel`.
// Returns absl::nullopt if clipping is not predicted, otherwise returns the
// suggested decrease in the analog gain level.
virtual absl::optional<int> EstimateClippedLevelStep(
int channel,
int level,
int default_step,
int min_mic_level,
int max_mic_level) const = 0;
// Analyses a frame of audio and stores the resulting metrics in `data_`.
virtual void Process(const AudioFrameView<const float>& frame) = 0;
};
// Creates a ClippingPredictor based on crest factor-based clipping event
// prediction.
std::unique_ptr<ClippingPredictor> CreateClippingEventPredictor(
int num_channels,
const AudioProcessing::Config::GainController1::AnalogGainController::
ClippingPredictor& config);
// Creates a ClippingPredictor based on crest factor-based peak estimation and
// fixed-step clipped level step estimation.
std::unique_ptr<ClippingPredictor> CreateFixedStepClippingPeakPredictor(
int num_channels,
const AudioProcessing::Config::GainController1::AnalogGainController::
ClippingPredictor& config);
// Creates a ClippingPredictor based on crest factor-based peak estimation and
// adaptive-step clipped level step estimation.
std::unique_ptr<ClippingPredictor> CreateAdaptiveStepClippingPeakPredictor(
int num_channels,
const AudioProcessing::Config::GainController1::AnalogGainController::
ClippingPredictor& config);
} // namespace webrtc
#endif // MODULES_AUDIO_PROCESSING_AGC_CLIPPING_PREDICTOR_H_