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ef5d5af3a0
This CL introduces an adaptive estimation of the early reverb in the estimation for the room reverberation. The benefits of this is that for room with long early reflections there is a lower risk of underestimating the reverberation. This CL is for a landing the code in https://webrtc-review.googlesource.com/c/src/+/87420, and the review of the code was done in that CL. The author of code is devicentepena@webrtc.org Bug: webrtc:9479, chromium:865397 Change-Id: Id6f57e2a684664aef96e8c502e66775f37da59da Reviewed-on: https://webrtc-review.googlesource.com/91162 Commit-Queue: Per Åhgren <peah@webrtc.org> Reviewed-by: Sam Zackrisson <saza@webrtc.org> Cr-Commit-Position: refs/heads/master@{#24146}
113 lines
3.6 KiB
C++
113 lines
3.6 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/aec3/reverb_frequency_response.h"
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#include <algorithm>
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#include <array>
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#include <cmath>
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#include <memory>
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#include <numeric>
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#include "api/array_view.h"
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#include "api/audio/echo_canceller3_config.h"
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#include "modules/audio_processing/aec3/aec3_common.h"
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#include "rtc_base/checks.h"
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#include "system_wrappers/include/field_trial.h"
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namespace webrtc {
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namespace {
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bool EnableSmoothUpdatesTailFreqResp() {
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return !field_trial::IsEnabled(
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"WebRTC-Aec3SmoothUpdatesTailFreqRespKillSwitch");
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}
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// Computes the ratio of the energies between the direct path and the tail. The
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// energy is computed in the power spectrum domain discarding the DC
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// contributions.
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float AverageDecayWithinFilter(
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rtc::ArrayView<const float> freq_resp_direct_path,
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rtc::ArrayView<const float> freq_resp_tail) {
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// Skipping the DC for the ratio computation
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constexpr size_t kSkipBins = 1;
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RTC_CHECK_EQ(freq_resp_direct_path.size(), freq_resp_tail.size());
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float direct_path_energy =
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std::accumulate(freq_resp_direct_path.begin() + kSkipBins,
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freq_resp_direct_path.end(), 0.f);
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if (direct_path_energy == 0.f) {
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return 0.f;
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}
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float tail_energy = std::accumulate(freq_resp_tail.begin() + kSkipBins,
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freq_resp_tail.end(), 0.f);
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return tail_energy / direct_path_energy;
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}
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} // namespace
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ReverbFrequencyResponse::ReverbFrequencyResponse()
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: enable_smooth_tail_response_updates_(EnableSmoothUpdatesTailFreqResp()) {
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tail_response_.fill(0.f);
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}
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ReverbFrequencyResponse::~ReverbFrequencyResponse() = default;
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void ReverbFrequencyResponse::Update(
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const std::vector<std::array<float, kFftLengthBy2Plus1>>&
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frequency_response,
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int filter_delay_blocks,
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const absl::optional<float>& linear_filter_quality,
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bool stationary_block) {
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if (!enable_smooth_tail_response_updates_) {
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Update(frequency_response, filter_delay_blocks, 0.1f);
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return;
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}
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if (stationary_block || !linear_filter_quality) {
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return;
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}
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Update(frequency_response, filter_delay_blocks, *linear_filter_quality);
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}
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void ReverbFrequencyResponse::Update(
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const std::vector<std::array<float, kFftLengthBy2Plus1>>&
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frequency_response,
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int filter_delay_blocks,
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float linear_filter_quality) {
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rtc::ArrayView<const float> freq_resp_tail(
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frequency_response[frequency_response.size() - 1]);
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rtc::ArrayView<const float> freq_resp_direct_path(
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frequency_response[filter_delay_blocks]);
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float average_decay =
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AverageDecayWithinFilter(freq_resp_direct_path, freq_resp_tail);
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const float smoothing = 0.2f * linear_filter_quality;
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average_decay_ += smoothing * (average_decay - average_decay_);
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for (size_t k = 0; k < kFftLengthBy2Plus1; ++k) {
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tail_response_[k] = freq_resp_direct_path[k] * average_decay_;
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}
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// TODO(devicentepena): Check if this should be done using a max that weights
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// both the lower and upper bands equally.
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for (size_t k = 1; k < kFftLengthBy2; ++k) {
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const float avg_neighbour =
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0.5f * (tail_response_[k - 1] + tail_response_[k + 1]);
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tail_response_[k] = std::max(tail_response_[k], avg_neighbour);
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}
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}
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} // namespace webrtc
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