webrtc/modules/audio_processing/agc2/saturation_protector.h
Alex Loiko 4bb1e4a1d5 Lower gain parameters for AGC2.
The AdaptiveAgc often boosts the signal outside of Float S16 range. It
is expected, which is why we have a limiter after it in the process
chain. But it turns out that this happens regularly even for simple
input examples. The output signal peaks can be as high as +4 dBFs for a
single speaker example (which should be easy). It leads to excessive
gain modulation by the limiter.

This CL is a new tuning designed to produce a safer gain. After this,
we shouldn't hit the saturation region of the limiter as often. But we
will still maintain a high gain.

We have a 'configurable kill-switch': the settings can be changed via
field trials WebRTC-Audio-Agc2Force(Initial|Extra)SaturationMargin.

Bug: webrtc:7494, chromium:892043
Change-Id: I5014377050c74c32ae8998282991141eae31cf58
Reviewed-on: https://webrtc-review.googlesource.com/c/102922
Commit-Queue: Alex Loiko <aleloi@webrtc.org>
Reviewed-by: Sam Zackrisson <saza@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25006}
2018-10-05 09:55:25 +00:00

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1.9 KiB
C++

/*
* 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.
*/
#ifndef MODULES_AUDIO_PROCESSING_AGC2_SATURATION_PROTECTOR_H_
#define MODULES_AUDIO_PROCESSING_AGC2_SATURATION_PROTECTOR_H_
#include <array>
#include "modules/audio_processing/agc2/agc2_common.h"
#include "modules/audio_processing/agc2/vad_with_level.h"
namespace webrtc {
class ApmDataDumper;
class SaturationProtector {
public:
explicit SaturationProtector(ApmDataDumper* apm_data_dumper);
// Update and return margin estimate. This method should be called
// whenever a frame is reliably classified as 'speech'.
//
// Returned value is in DB scale.
void UpdateMargin(const VadWithLevel::LevelAndProbability& vad_data,
float last_speech_level_estimate_dbfs);
// Returns latest computed margin. Used in cases when speech is not
// detected.
float LastMargin() const;
// Resets the internal memory.
void Reset();
void DebugDumpEstimate() const;
private:
// Computes a delayed envelope of peaks.
class PeakEnveloper {
public:
PeakEnveloper();
void Process(float frame_peak_dbfs);
float Query() const;
private:
size_t speech_time_in_estimate_ms_ = 0;
float current_superframe_peak_dbfs_ = -90.f;
size_t elements_in_buffer_ = 0;
std::array<float, kPeakEnveloperBufferSize> peak_delay_buffer_ = {};
};
ApmDataDumper* apm_data_dumper_;
float last_margin_;
PeakEnveloper peak_enveloper_;
float extra_saturation_margin_db_;
};
} // namespace webrtc
#endif // MODULES_AUDIO_PROCESSING_AGC2_SATURATION_PROTECTOR_H_