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.
106 lines
3.2 KiB
C++
106 lines
3.2 KiB
C++
/*
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* Copyright (c) 2022 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/speech_probability_buffer.h"
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#include <algorithm>
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#include "rtc_base/checks.h"
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namespace webrtc {
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namespace {
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constexpr float kActivityThreshold = 0.9f;
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constexpr int kNumAnalysisFrames = 100;
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// We use 12 in AGC2 adaptive digital, but with a slightly different logic.
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constexpr int kTransientWidthThreshold = 7;
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} // namespace
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SpeechProbabilityBuffer::SpeechProbabilityBuffer(
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float low_probability_threshold)
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: low_probability_threshold_(low_probability_threshold),
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probabilities_(kNumAnalysisFrames) {
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RTC_DCHECK_GE(low_probability_threshold, 0.0f);
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RTC_DCHECK_LE(low_probability_threshold, 1.0f);
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RTC_DCHECK(!probabilities_.empty());
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}
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void SpeechProbabilityBuffer::Update(float probability) {
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// Remove the oldest entry if the circular buffer is full.
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if (buffer_is_full_) {
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const float oldest_probability = probabilities_[buffer_index_];
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sum_probabilities_ -= oldest_probability;
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}
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// Check for transients.
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if (probability <= low_probability_threshold_) {
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// Set a probability lower than the threshold to zero.
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probability = 0.0f;
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// Check if this has been a transient.
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if (num_high_probability_observations_ <= kTransientWidthThreshold) {
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RemoveTransient();
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}
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num_high_probability_observations_ = 0;
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} else if (num_high_probability_observations_ <= kTransientWidthThreshold) {
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++num_high_probability_observations_;
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}
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// Update the circular buffer and the current sum.
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probabilities_[buffer_index_] = probability;
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sum_probabilities_ += probability;
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// Increment the buffer index and check for wrap-around.
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if (++buffer_index_ >= kNumAnalysisFrames) {
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buffer_index_ = 0;
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buffer_is_full_ = true;
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}
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}
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void SpeechProbabilityBuffer::RemoveTransient() {
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// Don't expect to be here if high-activity region is longer than
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// `kTransientWidthThreshold` or there has not been any transient.
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RTC_DCHECK_LE(num_high_probability_observations_, kTransientWidthThreshold);
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// Replace previously added probabilities with zero.
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int index =
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(buffer_index_ > 0) ? (buffer_index_ - 1) : (kNumAnalysisFrames - 1);
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while (num_high_probability_observations_-- > 0) {
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sum_probabilities_ -= probabilities_[index];
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probabilities_[index] = 0.0f;
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// Update the circular buffer index.
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index = (index > 0) ? (index - 1) : (kNumAnalysisFrames - 1);
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}
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}
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bool SpeechProbabilityBuffer::IsActiveSegment() const {
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if (!buffer_is_full_) {
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return false;
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}
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if (sum_probabilities_ < kActivityThreshold * kNumAnalysisFrames) {
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return false;
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}
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return true;
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}
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void SpeechProbabilityBuffer::Reset() {
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sum_probabilities_ = 0.0f;
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// Empty the circular buffer.
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buffer_index_ = 0;
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buffer_is_full_ = false;
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num_high_probability_observations_ = 0;
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}
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} // namespace webrtc
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