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/*
* Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "modules/audio_processing/agc2/rnn_vad/pitch_search.h"
#include <array>
#include <cstddef>
#include "rtc_base/checks.h"
namespace webrtc {
namespace rnn_vad {
PitchEstimator::PitchEstimator()
: pitch_buf_decimated_(kBufSize12kHz),
pitch_buf_decimated_view_(pitch_buf_decimated_.data(), kBufSize12kHz),
auto_corr_(kNumInvertedLags12kHz),
auto_corr_view_(auto_corr_.data(), kNumInvertedLags12kHz) {
RTC_DCHECK_EQ(kBufSize12kHz, pitch_buf_decimated_.size());
RTC_DCHECK_EQ(kNumInvertedLags12kHz, auto_corr_view_.size());
}
PitchEstimator::~PitchEstimator() = default;
PitchInfo PitchEstimator::Estimate(
rtc::ArrayView<const float, kBufSize24kHz> pitch_buf) {
// Perform the initial pitch search at 12 kHz.
Decimate2x(pitch_buf, pitch_buf_decimated_view_);
auto_corr_calculator_.ComputeOnPitchBuffer(pitch_buf_decimated_view_,
auto_corr_view_);
std::array<size_t, 2> pitch_candidates_inv_lags = FindBestPitchPeriods(
auto_corr_view_, pitch_buf_decimated_view_, kMaxPitch12kHz);
// Refine the pitch period estimation.
// The refinement is done using the pitch buffer that contains 24 kHz samples.
// Therefore, adapt the inverted lags in |pitch_candidates_inv_lags| from 12
// to 24 kHz.
pitch_candidates_inv_lags[0] *= 2;
pitch_candidates_inv_lags[1] *= 2;
size_t pitch_inv_lag_48kHz =
RefinePitchPeriod48kHz(pitch_buf, pitch_candidates_inv_lags);
// Look for stronger harmonics to find the final pitch period and its gain.
RTC_DCHECK_LT(pitch_inv_lag_48kHz, kMaxPitch48kHz);
last_pitch_48kHz_ = CheckLowerPitchPeriodsAndComputePitchGain(
pitch_buf, kMaxPitch48kHz - pitch_inv_lag_48kHz, last_pitch_48kHz_);
return last_pitch_48kHz_;
}
} // namespace rnn_vad
} // namespace webrtc
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