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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_CAPTURE_LEVELS_ADJUSTER_CAPTURE_LEVELS_ADJUSTER_H_
#define MODULES_AUDIO_PROCESSING_CAPTURE_LEVELS_ADJUSTER_CAPTURE_LEVELS_ADJUSTER_H_
#include <stddef.h>
#include "modules/audio_processing/audio_buffer.h"
#include "modules/audio_processing/capture_levels_adjuster/audio_samples_scaler.h"
namespace webrtc {
// Adjusts the level of the capture signal before and after all capture-side
// processing is done using a combination of explicitly specified gains
// and an emulated analog gain functionality where a specified analog level
// results in an additional gain. The pre-adjustment is achieved by combining
// the gain value `pre_gain` and the level `emulated_analog_mic_gain_level` to
// form a combined gain of `pre_gain`*`emulated_analog_mic_gain_level`/255 which
// is multiplied to each sample. The intention of the
// `emulated_analog_mic_gain_level` is to be controlled by the analog AGC
// functionality and to produce an emulated analog mic gain equal to
// `emulated_analog_mic_gain_level`/255. The post level adjustment is achieved
// by multiplying each sample with the value of `post_gain`. Any changes in the
// gains take are done smoothly over one frame and the scaled samples are
// clamped to fit into the allowed S16 sample range.
class CaptureLevelsAdjuster {
public:
// C-tor. The values for the level and the gains must fulfill
// 0 <= emulated_analog_mic_gain_level <= 255.
// 0.f <= pre_gain.
// 0.f <= post_gain.
CaptureLevelsAdjuster(bool emulated_analog_mic_gain_enabled,
int emulated_analog_mic_gain_level,
float pre_gain,
float post_gain);
CaptureLevelsAdjuster(const CaptureLevelsAdjuster&) = delete;
CaptureLevelsAdjuster& operator=(const CaptureLevelsAdjuster&) = delete;
// Adjusts the level of the signal. This should be called before any of the
// other processing is performed.
void ApplyPreLevelAdjustment(AudioBuffer& audio_buffer);
// Adjusts the level of the signal. This should be called after all of the
// other processing have been performed.
void ApplyPostLevelAdjustment(AudioBuffer& audio_buffer);
// Sets the gain to apply to each sample before any of the other processing is
// performed.
void SetPreGain(float pre_gain);
// Returns the total pre-adjustment gain applied, comprising both the pre_gain
// as well as the gain from the emulated analog mic, to each sample before any
// of the other processing is performed.
float GetPreAdjustmentGain() const { return pre_adjustment_gain_; }
// Sets the gain to apply to each sample after all of the other processing
// have been performed.
void SetPostGain(float post_gain);
// Sets the analog gain level to use for the emulated analog gain.
// `level` must be in the range [0...255].
void SetAnalogMicGainLevel(int level);
// Returns the current analog gain level used for the emulated analog gain.
int GetAnalogMicGainLevel() const { return emulated_analog_mic_gain_level_; }
private:
// Updates the value of `pre_adjustment_gain_` based on the supplied values
// for `pre_gain` and `emulated_analog_mic_gain_level_`.
void UpdatePreAdjustmentGain();
const bool emulated_analog_mic_gain_enabled_;
int emulated_analog_mic_gain_level_;
float pre_gain_;
float pre_adjustment_gain_;
AudioSamplesScaler pre_scaler_;
AudioSamplesScaler post_scaler_;
};
} // namespace webrtc
#endif // MODULES_AUDIO_PROCESSING_CAPTURE_LEVELS_ADJUSTER_CAPTURE_LEVELS_ADJUSTER_H_
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