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/*
* 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/fixed_gain_controller.h"
#include "api/array_view.h"
#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"
namespace webrtc {
namespace {
// Returns true when the gain factor is so close to 1 that it would
// not affect int16 samples.
bool CloseToOne(float gain_factor) {
return 1.f - 1.f / kMaxFloatS16Value <= gain_factor &&
gain_factor <= 1.f + 1.f / kMaxFloatS16Value;
}
} // namespace
FixedGainController::FixedGainController(ApmDataDumper* apm_data_dumper)
: FixedGainController(apm_data_dumper, "Agc2") {}
FixedGainController::FixedGainController(ApmDataDumper* apm_data_dumper,
std::string histogram_name_prefix)
: apm_data_dumper_(apm_data_dumper),
limiter_(48000, apm_data_dumper_, histogram_name_prefix) {
// Do update histograms.xml when adding name prefixes.
RTC_DCHECK(histogram_name_prefix == "" || histogram_name_prefix == "Test" ||
histogram_name_prefix == "AudioMixer" ||
histogram_name_prefix == "Agc2");
}
void FixedGainController::SetGain(float gain_to_apply_db) {
// Changes in gain_to_apply_ cause discontinuities. We assume
// gain_to_apply_ is set in the beginning of the call. If it is
// frequently changed, we should add interpolation between the
// values.
// The gain
RTC_DCHECK_LE(-50.f, gain_to_apply_db);
RTC_DCHECK_LE(gain_to_apply_db, 50.f);
const float previous_applied_gained = gain_to_apply_;
gain_to_apply_ = DbToRatio(gain_to_apply_db);
RTC_DCHECK_LT(0.f, gain_to_apply_);
RTC_DLOG(LS_INFO) << "Gain to apply: " << gain_to_apply_db << " db.";
// Reset the gain curve applier to quickly react on abrupt level changes
// caused by large changes of the applied gain.
if (previous_applied_gained != gain_to_apply_) {
limiter_.Reset();
}
}
void FixedGainController::SetSampleRate(size_t sample_rate_hz) {
limiter_.SetSampleRate(sample_rate_hz);
}
void FixedGainController::Process(AudioFrameView<float> signal) {
// Apply fixed digital gain. One of the
// planned usages of the FGC is to only use the limiter. In that
// case, the gain would be 1.0. Not doing the multiplications speeds
// it up considerably. Hence the check.
if (!CloseToOne(gain_to_apply_)) {
for (size_t k = 0; k < signal.num_channels(); ++k) {
rtc::ArrayView<float> channel_view = signal.channel(k);
for (auto& sample : channel_view) {
sample *= gain_to_apply_;
}
}
}
// Use the limiter.
limiter_.Process(signal);
// Dump data for debug.
const auto channel_view = signal.channel(0);
apm_data_dumper_->DumpRaw("agc2_fixed_digital_gain_curve_applier",
channel_view.size(), channel_view.data());
// Hard-clipping.
for (size_t k = 0; k < signal.num_channels(); ++k) {
rtc::ArrayView<float> channel_view = signal.channel(k);
for (auto& sample : channel_view) {
sample = rtc::SafeClamp(sample, kMinFloatS16Value, kMaxFloatS16Value);
}
}
}
float FixedGainController::LastAudioLevel() const {
return limiter_.LastAudioLevel();
}
} // namespace webrtc
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