1 files changed, 65 insertions, 0 deletions
diff --git a/third_party/libwebrtc/video/report_block_stats.cc b/third_party/libwebrtc/video/report_block_stats.cc
new file mode 100644
index 0000000000..bf60364682
--- /dev/null
+++ b/third_party/libwebrtc/video/report_block_stats.cc
@@ -0,0 +1,65 @@
+/*
+ *  Copyright (c) 2014 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 "video/report_block_stats.h"
+
+#include <algorithm>
+
+namespace webrtc {
+
+namespace {
+int FractionLost(uint32_t num_lost_sequence_numbers,
+                 uint32_t num_sequence_numbers) {
+  if (num_sequence_numbers == 0) {
+    return 0;
+  }
+  return ((num_lost_sequence_numbers * 255) + (num_sequence_numbers / 2)) /
+         num_sequence_numbers;
+}
+}  // namespace
+
+// Helper class for rtcp statistics.
+ReportBlockStats::ReportBlockStats()
+    : num_sequence_numbers_(0), num_lost_sequence_numbers_(0) {}
+
+ReportBlockStats::~ReportBlockStats() {}
+
+void ReportBlockStats::Store(uint32_t ssrc,
+                             int packets_lost,
+                             uint32_t extended_highest_sequence_number) {
+  Report report;
+  report.packets_lost = packets_lost;
+  report.extended_highest_sequence_number = extended_highest_sequence_number;
+
+  // Get diff with previous report block.
+  const auto prev_report = prev_reports_.find(ssrc);
+  if (prev_report != prev_reports_.end()) {
+    int seq_num_diff = report.extended_highest_sequence_number -
+                       prev_report->second.extended_highest_sequence_number;
+    int cum_loss_diff = report.packets_lost - prev_report->second.packets_lost;
+    if (seq_num_diff >= 0 && cum_loss_diff >= 0) {
+      // Update total number of packets/lost packets.
+      num_sequence_numbers_ += seq_num_diff;
+      num_lost_sequence_numbers_ += cum_loss_diff;
+    }
+  }
+  // Store current report block.
+  prev_reports_[ssrc] = report;
+}
+
+int ReportBlockStats::FractionLostInPercent() const {
+  if (num_sequence_numbers_ == 0) {
+    return -1;
+  }
+  return FractionLost(num_lost_sequence_numbers_, num_sequence_numbers_) * 100 /
+         255;
+}
+
+}  // namespace webrtc