VCMCodecTimer: Change filter from max to 95th percentile

webrtc/modules/video_coding/percentile_filter.cc

Index: webrtc/modules/video_coding/percentile_filter.cc
diff --git a/webrtc/modules/video_coding/percentile_filter.cc b/webrtc/modules/video_coding/percentile_filter.cc
new file mode 100644
index 0000000000000000000000000000000000000000..6495567540961c86a721b58de9ba99a51694973e
--- /dev/null
+++ b/webrtc/modules/video_coding/percentile_filter.cc
@@ -0,0 +1,70 @@
+/*
+ *  Copyright (c) 2016 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 "webrtc/modules/video_coding/percentile_filter.h"
+
+#include <iterator>
+
+#include "webrtc/base/checks.h"
+
+namespace webrtc {
+
+PercentileFilter::PercentileFilter(float percentile)
+    : percentile_(percentile),
+      percentile_it_(set_.begin()),
+      percentile_index_(0) {
+  RTC_CHECK_GE(percentile, 0.0f);
+  RTC_CHECK_LE(percentile, 1.0f);
+}
+
+void PercentileFilter::Insert(const int64_t& value) {
+  // Insert element at the upper bound.
+  set_.insert(value);
+  if (set_.size() == 1u) {
+    // First element inserted - initialize percentile iterator and index.
+    percentile_it_ = set_.begin();
+    percentile_index_ = 0;
+  } else if (value < *percentile_it_) {
+    // If new element is before us, increment |percentile_index_|.
+    ++percentile_index_;
+  }
+  UpdatePercentileIterator();
+}
+
+void PercentileFilter::Erase(const int64_t& value) {
+  std::multiset<int64_t>::const_iterator it = set_.lower_bound(value);
+  // Ignore erase operation if the element is not present in the current set.
+  if (it == set_.end() || *it != value)
+    return;
+  if (it == percentile_it_) {
+    // If same iterator, update to the following element. Index is not affected.
+    percentile_it_ = set_.erase(it);
+  } else {
+    set_.erase(it);
+    // If erased element was before us, decrement |percentile_index_|.
+    if (value <= *percentile_it_)
+      --percentile_index_;
+  }
+  UpdatePercentileIterator();
+}
+
+void PercentileFilter::UpdatePercentileIterator() {
+  if (set_.empty())
+    return;
+  const int64_t index = static_cast<int64_t>(percentile_ * (set_.size() - 1));
+  std::advance(percentile_it_, index - percentile_index_);
+  percentile_index_ = index;
+}
+
+int64_t PercentileFilter::GetPercentileValue() const {
+  return set_.empty() ? 0 : *percentile_it_;
+}
+
+}  // namespace webrtc