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0b489303d2
Bug: webrtc:12338 Change-Id: I85bff694dd2ead83c939c4d1945eff82e1296001 No-Presubmit: True Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/227161 Commit-Queue: Artem Titov <titovartem@webrtc.org> Reviewed-by: Harald Alvestrand <hta@webrtc.org> Cr-Commit-Position: refs/heads/master@{#34690}
120 lines
4.3 KiB
C++
120 lines
4.3 KiB
C++
/*
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* Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "modules/audio_processing/agc2/fixed_digital_level_estimator.h"
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#include <algorithm>
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#include <cmath>
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#include "api/array_view.h"
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#include "modules/audio_processing/logging/apm_data_dumper.h"
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#include "rtc_base/checks.h"
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namespace webrtc {
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namespace {
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constexpr float kInitialFilterStateLevel = 0.f;
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// Instant attack.
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constexpr float kAttackFilterConstant = 0.f;
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// This is computed from kDecayMs by
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// 10 ** (-1/20 * subframe_duration / kDecayMs).
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// `subframe_duration` is |kFrameDurationMs / kSubFramesInFrame|.
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// kDecayMs is defined in agc2_testing_common.h
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constexpr float kDecayFilterConstant = 0.9998848773724686f;
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} // namespace
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FixedDigitalLevelEstimator::FixedDigitalLevelEstimator(
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int sample_rate_hz,
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ApmDataDumper* apm_data_dumper)
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: apm_data_dumper_(apm_data_dumper),
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filter_state_level_(kInitialFilterStateLevel) {
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SetSampleRate(sample_rate_hz);
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CheckParameterCombination();
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RTC_DCHECK(apm_data_dumper_);
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apm_data_dumper_->DumpRaw("agc2_level_estimator_samplerate", sample_rate_hz);
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}
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void FixedDigitalLevelEstimator::CheckParameterCombination() {
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RTC_DCHECK_GT(samples_in_frame_, 0);
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RTC_DCHECK_LE(kSubFramesInFrame, samples_in_frame_);
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RTC_DCHECK_EQ(samples_in_frame_ % kSubFramesInFrame, 0);
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RTC_DCHECK_GT(samples_in_sub_frame_, 1);
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}
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std::array<float, kSubFramesInFrame> FixedDigitalLevelEstimator::ComputeLevel(
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const AudioFrameView<const float>& float_frame) {
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RTC_DCHECK_GT(float_frame.num_channels(), 0);
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RTC_DCHECK_EQ(float_frame.samples_per_channel(), samples_in_frame_);
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// Compute max envelope without smoothing.
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std::array<float, kSubFramesInFrame> envelope{};
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for (size_t channel_idx = 0; channel_idx < float_frame.num_channels();
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++channel_idx) {
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const auto channel = float_frame.channel(channel_idx);
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for (int sub_frame = 0; sub_frame < kSubFramesInFrame; ++sub_frame) {
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for (int sample_in_sub_frame = 0;
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sample_in_sub_frame < samples_in_sub_frame_; ++sample_in_sub_frame) {
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envelope[sub_frame] =
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std::max(envelope[sub_frame],
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std::abs(channel[sub_frame * samples_in_sub_frame_ +
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sample_in_sub_frame]));
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}
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}
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}
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// Make sure envelope increases happen one step earlier so that the
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// corresponding *gain decrease* doesn't miss a sudden signal
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// increase due to interpolation.
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for (int sub_frame = 0; sub_frame < kSubFramesInFrame - 1; ++sub_frame) {
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if (envelope[sub_frame] < envelope[sub_frame + 1]) {
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envelope[sub_frame] = envelope[sub_frame + 1];
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}
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}
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// Add attack / decay smoothing.
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for (int sub_frame = 0; sub_frame < kSubFramesInFrame; ++sub_frame) {
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const float envelope_value = envelope[sub_frame];
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if (envelope_value > filter_state_level_) {
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envelope[sub_frame] = envelope_value * (1 - kAttackFilterConstant) +
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filter_state_level_ * kAttackFilterConstant;
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} else {
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envelope[sub_frame] = envelope_value * (1 - kDecayFilterConstant) +
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filter_state_level_ * kDecayFilterConstant;
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}
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filter_state_level_ = envelope[sub_frame];
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// Dump data for debug.
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RTC_DCHECK(apm_data_dumper_);
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const auto channel = float_frame.channel(0);
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apm_data_dumper_->DumpRaw("agc2_level_estimator_samples",
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samples_in_sub_frame_,
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&channel[sub_frame * samples_in_sub_frame_]);
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apm_data_dumper_->DumpRaw("agc2_level_estimator_level",
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envelope[sub_frame]);
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}
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return envelope;
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}
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void FixedDigitalLevelEstimator::SetSampleRate(int sample_rate_hz) {
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samples_in_frame_ =
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rtc::CheckedDivExact(sample_rate_hz * kFrameDurationMs, 1000);
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samples_in_sub_frame_ =
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rtc::CheckedDivExact(samples_in_frame_, kSubFramesInFrame);
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CheckParameterCombination();
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}
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void FixedDigitalLevelEstimator::Reset() {
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filter_state_level_ = kInitialFilterStateLevel;
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}
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} // namespace webrtc
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