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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.
*/
#include "modules/audio_processing/capture_levels_adjuster/capture_levels_adjuster.h"
#include "modules/audio_processing/audio_buffer.h"
#include "rtc_base/checks.h"
#include "rtc_base/numerics/safe_minmax.h"
namespace webrtc {
namespace {
constexpr int kMinAnalogMicGainLevel = 0;
constexpr int kMaxAnalogMicGainLevel = 255;
float ComputeLevelBasedGain(int emulated_analog_mic_gain_level) {
static_assert(
kMinAnalogMicGainLevel == 0,
"The minimum gain level must be 0 for the maths below to work.");
static_assert(kMaxAnalogMicGainLevel > 0,
"The minimum gain level must be larger than 0 for the maths "
"below to work.");
constexpr float kGainToLevelMultiplier = 1.f / kMaxAnalogMicGainLevel;
RTC_DCHECK_GE(emulated_analog_mic_gain_level, kMinAnalogMicGainLevel);
RTC_DCHECK_LE(emulated_analog_mic_gain_level, kMaxAnalogMicGainLevel);
return kGainToLevelMultiplier * emulated_analog_mic_gain_level;
}
float ComputePreGain(float pre_gain,
int emulated_analog_mic_gain_level,
bool emulated_analog_mic_gain_enabled) {
return emulated_analog_mic_gain_enabled
? pre_gain * ComputeLevelBasedGain(emulated_analog_mic_gain_level)
: pre_gain;
}
} // namespace
CaptureLevelsAdjuster::CaptureLevelsAdjuster(
bool emulated_analog_mic_gain_enabled,
int emulated_analog_mic_gain_level,
float pre_gain,
float post_gain)
: emulated_analog_mic_gain_enabled_(emulated_analog_mic_gain_enabled),
emulated_analog_mic_gain_level_(emulated_analog_mic_gain_level),
pre_gain_(pre_gain),
pre_adjustment_gain_(ComputePreGain(pre_gain_,
emulated_analog_mic_gain_level_,
emulated_analog_mic_gain_enabled_)),
pre_scaler_(pre_adjustment_gain_),
post_scaler_(post_gain) {}
void CaptureLevelsAdjuster::ApplyPreLevelAdjustment(AudioBuffer& audio_buffer) {
pre_scaler_.Process(audio_buffer);
}
void CaptureLevelsAdjuster::ApplyPostLevelAdjustment(
AudioBuffer& audio_buffer) {
post_scaler_.Process(audio_buffer);
}
void CaptureLevelsAdjuster::SetPreGain(float pre_gain) {
pre_gain_ = pre_gain;
UpdatePreAdjustmentGain();
}
void CaptureLevelsAdjuster::SetPostGain(float post_gain) {
post_scaler_.SetGain(post_gain);
}
void CaptureLevelsAdjuster::SetAnalogMicGainLevel(int level) {
RTC_DCHECK_GE(level, kMinAnalogMicGainLevel);
RTC_DCHECK_LE(level, kMaxAnalogMicGainLevel);
int clamped_level =
rtc::SafeClamp(level, kMinAnalogMicGainLevel, kMaxAnalogMicGainLevel);
emulated_analog_mic_gain_level_ = clamped_level;
UpdatePreAdjustmentGain();
}
void CaptureLevelsAdjuster::UpdatePreAdjustmentGain() {
pre_adjustment_gain_ =
ComputePreGain(pre_gain_, emulated_analog_mic_gain_level_,
emulated_analog_mic_gain_enabled_);
pre_scaler_.SetGain(pre_adjustment_gain_);
}
} // namespace webrtc