1 files changed, 56 insertions, 0 deletions
diff --git a/third_party/libwebrtc/modules/audio_processing/transient/voice_probability_delay_unit.cc b/third_party/libwebrtc/modules/audio_processing/transient/voice_probability_delay_unit.cc
new file mode 100644
index 0000000000..27b2b42b38
--- /dev/null
+++ b/third_party/libwebrtc/modules/audio_processing/transient/voice_probability_delay_unit.cc
@@ -0,0 +1,56 @@
+/*
+ *  Copyright (c) 2022 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/transient/voice_probability_delay_unit.h"
+
+#include <array>
+
+#include "rtc_base/checks.h"
+
+namespace webrtc {
+
+VoiceProbabilityDelayUnit::VoiceProbabilityDelayUnit(int delay_num_samples,
+                                                     int sample_rate_hz) {
+  Initialize(delay_num_samples, sample_rate_hz);
+}
+
+void VoiceProbabilityDelayUnit::Initialize(int delay_num_samples,
+                                           int sample_rate_hz) {
+  RTC_DCHECK_GE(delay_num_samples, 0);
+  RTC_DCHECK_LE(delay_num_samples, sample_rate_hz / 50)
+      << "The implementation does not support delays greater than 20 ms.";
+  int frame_size = rtc::CheckedDivExact(sample_rate_hz, 100);  // 10 ms.
+  if (delay_num_samples <= frame_size) {
+    weights_[0] = 0.0f;
+    weights_[1] = static_cast<float>(delay_num_samples) / frame_size;
+    weights_[2] =
+        static_cast<float>(frame_size - delay_num_samples) / frame_size;
+  } else {
+    delay_num_samples -= frame_size;
+    weights_[0] = static_cast<float>(delay_num_samples) / frame_size;
+    weights_[1] =
+        static_cast<float>(frame_size - delay_num_samples) / frame_size;
+    weights_[2] = 0.0f;
+  }
+
+  // Resets the delay unit.
+  last_probabilities_.fill(0.0f);
+}
+
+float VoiceProbabilityDelayUnit::Delay(float voice_probability) {
+  float weighted_probability = weights_[0] * last_probabilities_[0] +
+                               weights_[1] * last_probabilities_[1] +
+                               weights_[2] * voice_probability;
+  last_probabilities_[0] = last_probabilities_[1];
+  last_probabilities_[1] = voice_probability;
+  return weighted_probability;
+}
+
+}  // namespace webrtc