c6abf6cd3f
Some API deprecation -- ExperimentalAgc and ExperimentalNs are gone. We're continuing to carry iSAC even though it's gone upstream, but maybe we'll want to drop that soon.
91 lines
3.5 KiB
C++
91 lines
3.5 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/rnn_vad/features_extraction.h"
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#include <array>
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#include "modules/audio_processing/agc2/rnn_vad/lp_residual.h"
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#include "rtc_base/checks.h"
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namespace webrtc {
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namespace rnn_vad {
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namespace {
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// Computed as `scipy.signal.butter(N=2, Wn=60/24000, btype='highpass')`.
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constexpr BiQuadFilter::Config kHpfConfig24k{
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{0.99446179f, -1.98892358f, 0.99446179f},
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{-1.98889291f, 0.98895425f}};
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} // namespace
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FeaturesExtractor::FeaturesExtractor(const AvailableCpuFeatures& cpu_features)
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: use_high_pass_filter_(false),
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hpf_(kHpfConfig24k),
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pitch_buf_24kHz_(),
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pitch_buf_24kHz_view_(pitch_buf_24kHz_.GetBufferView()),
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lp_residual_(kBufSize24kHz),
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lp_residual_view_(lp_residual_.data(), kBufSize24kHz),
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pitch_estimator_(cpu_features),
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reference_frame_view_(pitch_buf_24kHz_.GetMostRecentValuesView()) {
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RTC_DCHECK_EQ(kBufSize24kHz, lp_residual_.size());
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Reset();
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}
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FeaturesExtractor::~FeaturesExtractor() = default;
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void FeaturesExtractor::Reset() {
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pitch_buf_24kHz_.Reset();
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spectral_features_extractor_.Reset();
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if (use_high_pass_filter_) {
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hpf_.Reset();
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}
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}
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bool FeaturesExtractor::CheckSilenceComputeFeatures(
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rtc::ArrayView<const float, kFrameSize10ms24kHz> samples,
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rtc::ArrayView<float, kFeatureVectorSize> feature_vector) {
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// Pre-processing.
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if (use_high_pass_filter_) {
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std::array<float, kFrameSize10ms24kHz> samples_filtered;
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hpf_.Process(samples, samples_filtered);
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// Feed buffer with the pre-processed version of `samples`.
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pitch_buf_24kHz_.Push(samples_filtered);
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} else {
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// Feed buffer with `samples`.
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pitch_buf_24kHz_.Push(samples);
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}
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// Extract the LP residual.
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float lpc_coeffs[kNumLpcCoefficients];
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ComputeAndPostProcessLpcCoefficients(pitch_buf_24kHz_view_, lpc_coeffs);
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ComputeLpResidual(lpc_coeffs, pitch_buf_24kHz_view_, lp_residual_view_);
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// Estimate pitch on the LP-residual and write the normalized pitch period
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// into the output vector (normalization based on training data stats).
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pitch_period_48kHz_ = pitch_estimator_.Estimate(lp_residual_view_);
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feature_vector[kFeatureVectorSize - 2] = 0.01f * (pitch_period_48kHz_ - 300);
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// Extract lagged frames (according to the estimated pitch period).
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RTC_DCHECK_LE(pitch_period_48kHz_ / 2, kMaxPitch24kHz);
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auto lagged_frame = pitch_buf_24kHz_view_.subview(
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kMaxPitch24kHz - pitch_period_48kHz_ / 2, kFrameSize20ms24kHz);
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// Analyze reference and lagged frames checking if silence has been detected
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// and write the feature vector.
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return spectral_features_extractor_.CheckSilenceComputeFeatures(
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reference_frame_view_, {lagged_frame.data(), kFrameSize20ms24kHz},
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{feature_vector.data() + kNumLowerBands, kNumBands - kNumLowerBands},
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{feature_vector.data(), kNumLowerBands},
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{feature_vector.data() + kNumBands, kNumLowerBands},
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{feature_vector.data() + kNumBands + kNumLowerBands, kNumLowerBands},
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{feature_vector.data() + kNumBands + 2 * kNumLowerBands, kNumLowerBands},
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&feature_vector[kFeatureVectorSize - 1]);
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}
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} // namespace rnn_vad
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} // namespace webrtc
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