mirror of
https://github.com/danog/libtgvoip.git
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5caaaafa42
I'm now using the entire audio processing module from WebRTC as opposed to individual DSP algorithms pulled from there before. Seems to work better this way.
110 lines
3.4 KiB
C++
110 lines
3.4 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 <stddef.h>
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#include <algorithm>
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#include <array>
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#include <numeric>
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#include "api/array_view.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, 0.5f);
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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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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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