Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 79 insertions, 0 deletions

diff --git a/third_party/libwebrtc/modules/congestion_controller/goog_cc/link_capacity_estimator.cc b/third_party/libwebrtc/modules/congestion_controller/goog_cc/link_capacity_estimator.cc
new file mode 100644
index 0000000000..05664bcac7
--- /dev/null
+++ b/third_party/libwebrtc/modules/congestion_controller/goog_cc/link_capacity_estimator.cc
@@ -0,0 +1,79 @@
+/*
+ *  Copyright 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/congestion_controller/goog_cc/link_capacity_estimator.h"
+
+#include <algorithm>
+#include <cmath>
+
+#include "api/units/data_rate.h"
+#include "rtc_base/numerics/safe_minmax.h"
+
+namespace webrtc {
+LinkCapacityEstimator::LinkCapacityEstimator() {}
+
+DataRate LinkCapacityEstimator::UpperBound() const {
+  if (estimate_kbps_.has_value())
+    return DataRate::KilobitsPerSec(estimate_kbps_.value() +
+                                    3 * deviation_estimate_kbps());
+  return DataRate::Infinity();
+}
+
+DataRate LinkCapacityEstimator::LowerBound() const {
+  if (estimate_kbps_.has_value())
+    return DataRate::KilobitsPerSec(
+        std::max(0.0, estimate_kbps_.value() - 3 * deviation_estimate_kbps()));
+  return DataRate::Zero();
+}
+
+void LinkCapacityEstimator::Reset() {
+  estimate_kbps_.reset();
+}
+
+void LinkCapacityEstimator::OnOveruseDetected(DataRate acknowledged_rate) {
+  Update(acknowledged_rate, 0.05);
+}
+
+void LinkCapacityEstimator::OnProbeRate(DataRate probe_rate) {
+  Update(probe_rate, 0.5);
+}
+
+void LinkCapacityEstimator::Update(DataRate capacity_sample, double alpha) {
+  double sample_kbps = capacity_sample.kbps();
+  if (!estimate_kbps_.has_value()) {
+    estimate_kbps_ = sample_kbps;
+  } else {
+    estimate_kbps_ = (1 - alpha) * estimate_kbps_.value() + alpha * sample_kbps;
+  }
+  // Estimate the variance of the link capacity estimate and normalize the
+  // variance with the link capacity estimate.
+  const double norm = std::max(estimate_kbps_.value(), 1.0);
+  double error_kbps = estimate_kbps_.value() - sample_kbps;
+  deviation_kbps_ =
+      (1 - alpha) * deviation_kbps_ + alpha * error_kbps * error_kbps / norm;
+  // 0.4 ~= 14 kbit/s at 500 kbit/s
+  // 2.5f ~= 35 kbit/s at 500 kbit/s
+  deviation_kbps_ = rtc::SafeClamp(deviation_kbps_, 0.4f, 2.5f);
+}
+
+bool LinkCapacityEstimator::has_estimate() const {
+  return estimate_kbps_.has_value();
+}
+
+DataRate LinkCapacityEstimator::estimate() const {
+  return DataRate::KilobitsPerSec(*estimate_kbps_);
+}
+
+double LinkCapacityEstimator::deviation_estimate_kbps() const {
+  // Calculate the max bit rate std dev given the normalized
+  // variance and the current throughput bitrate. The standard deviation will
+  // only be used if estimate_kbps_ has a value.
+  return sqrt(deviation_kbps_ * estimate_kbps_.value());
+}
+}  // namespace webrtc