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diff --git a/third_party/libwebrtc/modules/video_coding/utility/frame_dropper.h b/third_party/libwebrtc/modules/video_coding/utility/frame_dropper.h
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+/*
+ *  Copyright (c) 2011 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.
+ */
+
+#ifndef MODULES_VIDEO_CODING_UTILITY_FRAME_DROPPER_H_
+#define MODULES_VIDEO_CODING_UTILITY_FRAME_DROPPER_H_
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include "rtc_base/numerics/exp_filter.h"
+
+namespace webrtc {
+
+// The Frame Dropper implements a variant of the leaky bucket algorithm
+// for keeping track of when to drop frames to avoid bit rate
+// over use when the encoder can't keep its bit rate.
+class FrameDropper {
+ public:
+  FrameDropper();
+  ~FrameDropper();
+
+  // Resets the FrameDropper to its initial state.
+  void Reset();
+
+  void Enable(bool enable);
+
+  // Answers the question if it's time to drop a frame if we want to reach a
+  // given frame rate. Must be called for every frame.
+  //
+  // Return value     : True if we should drop the current frame.
+  bool DropFrame();
+
+  // Updates the FrameDropper with the size of the latest encoded frame.
+  // The FrameDropper calculates a new drop ratio (can be seen as the
+  // probability to drop a frame) and updates its internal statistics.
+  //
+  // Input:
+  //          - framesize_bytes    : The size of the latest frame returned
+  //                                 from the encoder.
+  //          - delta_frame        : True if the encoder returned a delta frame.
+  void Fill(size_t framesize_bytes, bool delta_frame);
+
+  void Leak(uint32_t input_framerate);
+
+  // Sets the target bit rate and the frame rate produced by the camera.
+  //
+  // Input:
+  //          - bitrate       : The target bit rate.
+  void SetRates(float bitrate, float incoming_frame_rate);
+
+ private:
+  void UpdateRatio();
+  void CapAccumulator();
+
+  rtc::ExpFilter key_frame_ratio_;
+  rtc::ExpFilter delta_frame_size_avg_kbits_;
+
+  // Key frames and large delta frames are not immediately accumulated in the
+  // bucket since they can immediately overflow the bucket leading to large
+  // drops on the following packets that may be much smaller. Instead these
+  // large frames are accumulated over several frames when the bucket leaks.
+
+  // `large_frame_accumulation_spread_` represents the number of frames over
+  // which a large frame is accumulated.
+  float large_frame_accumulation_spread_;
+  // `large_frame_accumulation_count_` represents the number of frames left
+  // to finish accumulating a large frame.
+  int large_frame_accumulation_count_;
+  // `large_frame_accumulation_chunk_size_` represents the size of a single
+  // chunk for large frame accumulation.
+  float large_frame_accumulation_chunk_size_;
+
+  float accumulator_;
+  float accumulator_max_;
+  float target_bitrate_;
+  bool drop_next_;
+  rtc::ExpFilter drop_ratio_;
+  int drop_count_;
+  float incoming_frame_rate_;
+  bool was_below_max_;
+  bool enabled_;
+  const float max_drop_duration_secs_;
+};
+
+}  // namespace webrtc
+
+#endif  // MODULES_VIDEO_CODING_UTILITY_FRAME_DROPPER_H_