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/aec3/echo_audibility.h"
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#include <algorithm>
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#include <cmath>
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#include <utility>
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#include <vector>
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#include "api/array_view.h"
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#include "modules/audio_processing/aec3/block_buffer.h"
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#include "modules/audio_processing/aec3/spectrum_buffer.h"
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#include "modules/audio_processing/aec3/stationarity_estimator.h"
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namespace webrtc {
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EchoAudibility::EchoAudibility(bool use_render_stationarity_at_init)
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: use_render_stationarity_at_init_(use_render_stationarity_at_init) {
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Reset();
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}
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EchoAudibility::~EchoAudibility() = default;
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void EchoAudibility::Update(const RenderBuffer& render_buffer,
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rtc::ArrayView<const float> average_reverb,
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int delay_blocks,
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bool external_delay_seen) {
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UpdateRenderNoiseEstimator(render_buffer.GetSpectrumBuffer(),
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render_buffer.GetBlockBuffer(),
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external_delay_seen);
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if (external_delay_seen || use_render_stationarity_at_init_) {
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UpdateRenderStationarityFlags(render_buffer, average_reverb, delay_blocks);
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}
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}
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void EchoAudibility::Reset() {
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render_stationarity_.Reset();
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non_zero_render_seen_ = false;
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render_spectrum_write_prev_ = absl::nullopt;
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}
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void EchoAudibility::UpdateRenderStationarityFlags(
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const RenderBuffer& render_buffer,
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rtc::ArrayView<const float> average_reverb,
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int min_channel_delay_blocks) {
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const SpectrumBuffer& spectrum_buffer = render_buffer.GetSpectrumBuffer();
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int idx_at_delay = spectrum_buffer.OffsetIndex(spectrum_buffer.read,
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min_channel_delay_blocks);
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int num_lookahead = render_buffer.Headroom() - min_channel_delay_blocks + 1;
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num_lookahead = std::max(0, num_lookahead);
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render_stationarity_.UpdateStationarityFlags(spectrum_buffer, average_reverb,
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idx_at_delay, num_lookahead);
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}
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void EchoAudibility::UpdateRenderNoiseEstimator(
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const SpectrumBuffer& spectrum_buffer,
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const BlockBuffer& block_buffer,
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bool external_delay_seen) {
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if (!render_spectrum_write_prev_) {
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render_spectrum_write_prev_ = spectrum_buffer.write;
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render_block_write_prev_ = block_buffer.write;
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return;
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}
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int render_spectrum_write_current = spectrum_buffer.write;
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if (!non_zero_render_seen_ && !external_delay_seen) {
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non_zero_render_seen_ = !IsRenderTooLow(block_buffer);
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}
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if (non_zero_render_seen_) {
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for (int idx = render_spectrum_write_prev_.value();
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idx != render_spectrum_write_current;
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idx = spectrum_buffer.DecIndex(idx)) {
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render_stationarity_.UpdateNoiseEstimator(spectrum_buffer.buffer[idx]);
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}
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}
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render_spectrum_write_prev_ = render_spectrum_write_current;
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}
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bool EchoAudibility::IsRenderTooLow(const BlockBuffer& block_buffer) {
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const int num_render_channels =
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static_cast<int>(block_buffer.buffer[0].NumChannels());
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bool too_low = false;
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const int render_block_write_current = block_buffer.write;
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if (render_block_write_current == render_block_write_prev_) {
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too_low = true;
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} else {
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for (int idx = render_block_write_prev_; idx != render_block_write_current;
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idx = block_buffer.IncIndex(idx)) {
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float max_abs_over_channels = 0.f;
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for (int ch = 0; ch < num_render_channels; ++ch) {
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rtc::ArrayView<const float, kBlockSize> block =
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block_buffer.buffer[idx].View(/*band=*/0, /*channel=*/ch);
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auto r = std::minmax_element(block.cbegin(), block.cend());
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float max_abs_channel =
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std::max(std::fabs(*r.first), std::fabs(*r.second));
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max_abs_over_channels =
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std::max(max_abs_over_channels, max_abs_channel);
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}
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if (max_abs_over_channels < 10.f) {
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too_low = true; // Discards all blocks if one of them is too low.
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break;
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}
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}
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}
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render_block_write_prev_ = render_block_write_current;
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return too_low;
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}
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} // namespace webrtc
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