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Set a positive initial gain in the Adaptive Digital GC.

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If the adaptive gain is too low, we raise it slowly and only during
speech.

The CL gives better behavior at the start of a call. If the gain is too
high, the fixed-digital limits it. The gain is also quickly reduced by
the AdaptiveGainApplier.

Bug: webrtc:7494
Change-Id: I683f1e3e463cddec2d91f6c7f15c73e744430034
Reviewed-on: https://webrtc-review.googlesource.com/71484
Commit-Queue: Alex Loiko <aleloi@webrtc.org>
Reviewed-by: Alessio Bazzica <alessiob@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23053}
This commit is contained in:
Alex Loiko 2018-04-20 15:28:45 +02:00 committed by Commit Bot
parent d4043f69ae
commit 95141d91d8
5 changed files with 16 additions and 16 deletions
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3
modules/audio_processing/agc2/adaptive_digital_gain_applier.cc
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@ -68,8 +68,7 @@ float ComputeGainChangeThisFrameDb(float target_gain_db,
AdaptiveDigitalGainApplier::AdaptiveDigitalGainApplier(
ApmDataDumper* apm_data_dumper)
: gain_applier_(false, 1.f), // Initial gain is 1, and we do not
// clip after gain.
: gain_applier_(false, DbToRatio(last_gain_db_)),
apm_data_dumper_(apm_data_dumper) {}
void AdaptiveDigitalGainApplier::Process(

3
modules/audio_processing/agc2/adaptive_digital_gain_applier.h
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@ -11,6 +11,7 @@
#ifndef MODULES_AUDIO_PROCESSING_AGC2_ADAPTIVE_DIGITAL_GAIN_APPLIER_H_
#define MODULES_AUDIO_PROCESSING_AGC2_ADAPTIVE_DIGITAL_GAIN_APPLIER_H_
#include "modules/audio_processing/agc2/agc2_common.h"
#include "modules/audio_processing/agc2/gain_applier.h"
#include "modules/audio_processing/include/audio_frame_view.h"
#include "modules/audio_processing/vad/vad_with_level.h"
@ -30,7 +31,7 @@ class AdaptiveDigitalGainApplier {
AudioFrameView<float> float_frame);
private:
float last_gain_db_ = 0.f;
float last_gain_db_ = kInitialAdaptiveDigitalGainDb;
GainApplier gain_applier_;
// For some combinations of noise and speech probability, increasing

19
modules/audio_processing/agc2/adaptive_digital_gain_applier_unittest.cc
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@ -145,7 +145,7 @@ TEST(AutomaticGainController2AdaptiveGainApplier, GainIsRampedInAFrame) {
rtc::ArrayView<const VadWithLevel::LevelAndProbability>(&kVadSpeech, 1),
fake_audio.float_frame_view());
float maximal_difference = 0.f;
float current_value = 1.f;
float current_value = 1.f * DbToRatio(kInitialAdaptiveDigitalGainDb);
for (const auto& x : fake_audio.float_frame_view().channel(0)) {
const float difference = std::abs(x - current_value);
maximal_difference = std::max(maximal_difference, difference);
@ -164,22 +164,27 @@ TEST(AutomaticGainController2AdaptiveGainApplier, NoiseLimitsGain) {
constexpr float initial_level_dbfs = -25.f;
constexpr int num_samples = 480;
constexpr int num_frames = 100;
constexpr int num_initial_frames =
kInitialAdaptiveDigitalGainDb / kMaxGainChangePerFrameDb;
constexpr int num_frames = 50;
ASSERT_GT(kWithNoiseDbfs, kMaxNoiseLevelDbfs) << "kWithNoiseDbfs is too low";
for (int i = 0; i < num_frames; ++i) {
for (int i = 0; i < num_initial_frames + num_frames; ++i) {
VectorFloatFrame fake_audio(1, num_samples, 1.f);
gain_applier.Process(
initial_level_dbfs, kWithNoiseDbfs,
rtc::ArrayView<const VadWithLevel::LevelAndProbability>(&kVadSpeech, 1),
fake_audio.float_frame_view());
const float maximal_ratio =
*std::max_element(fake_audio.float_frame_view().channel(0).begin(),
fake_audio.float_frame_view().channel(0).end());
// Wait so that the adaptive gain applier has time to lower the gain.
if (i > num_initial_frames) {
const float maximal_ratio =
*std::max_element(fake_audio.float_frame_view().channel(0).begin(),
fake_audio.float_frame_view().channel(0).end());
EXPECT_NEAR(maximal_ratio, 1.f, 0.001f);
EXPECT_NEAR(maximal_ratio, 1.f, 0.001f);
}
}
}
} // namespace webrtc

1
modules/audio_processing/agc2/agc2_common.h
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@ -33,6 +33,7 @@ constexpr float kMaxGainChangePerFrameDb =
kMaxGainChangePerSecondDb * kFrameDurationMs / 1000.f;
constexpr float kHeadroomDbfs = 1.f;
constexpr float kMaxGainDb = 30.f;
constexpr float kInitialAdaptiveDigitalGainDb = 8.f;
// This parameter must be tuned together with the noise estimator.
constexpr float kMaxNoiseLevelDbfs = -50.f;

6
modules/audio_processing/gain_controller2_unittest.cc
View File

@ -80,12 +80,6 @@ TEST(GainController2, Usage) {
SetAudioBufferSamples(sample_value, &ab);
AudioProcessing::Config::GainController2 config;
// Check that samples are not modified when the fixed gain is 0 dB.
config.fixed_gain_db = 0.f;
gain_controller2->ApplyConfig(config);
gain_controller2->Process(&ab);
EXPECT_EQ(ab.channels_f()[0][0], sample_value);
// Check that samples are amplified when the fixed gain is greater than 0 dB.
config.fixed_gain_db = 5.f;
gain_controller2->ApplyConfig(config);