Limit target encoder bitrate change frequency in the frame scheduler.

remoting/protocol/webrtc_frame_scheduler_simple.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef REMOTING_PROTOCOL_WEBRTC_FRAME_SCHEDULER_SIMPLE_H_
 #define REMOTING_PROTOCOL_WEBRTC_FRAME_SCHEDULER_SIMPLE_H_
 
 #include "remoting/protocol/webrtc_frame_scheduler.h"
 
+#include <queue>
+
 #include "base/threading/thread_checker.h"
 #include "base/timer/timer.h"
 #include "remoting/base/leaky_bucket.h"
 #include "remoting/base/running_samples.h"
 #include "remoting/protocol/video_channel_state_observer.h"
 
 namespace remoting {
 namespace protocol {
 
 // WebrtcFrameSchedulerSimple is a simple implementation of WebrtcFrameScheduler
@@ skipping 16 matching lines @@
              const base::Closure& capture_callback) override;
   void Pause(bool pause) override;
   bool GetEncoderFrameParams(
       const webrtc::DesktopFrame& frame,
       WebrtcVideoEncoder::FrameParams* params_out) override;
   void OnFrameEncoded(const WebrtcVideoEncoder::EncodedFrame& encoded_frame,
                       const webrtc::EncodedImageCallback::Result& send_result,
                       HostFrameStats* frame_stats) override;
 
  private:
+  // Helper class used to calculate target encoder bitrate.
+  class EncoderBitrateFilter {
+   public:
+    EncoderBitrateFilter();
+    ~EncoderBitrateFilter();
+
+    void SetBandwidthEstimate(int bandwidth_kbps, base::TimeTicks now);
+    int GetTargetBitrateKbps(webrtc::DesktopSize size, base::TimeTicks now);
+
+   private:
+    std::queue<std::pair<base::TimeTicks, int>> bandwidth_samples_;
+    int bandwidth_samples_sum_ = 0;
+
+    int current_target_bitrate_;
+  };
+
   void ScheduleNextFrame(base::TimeTicks now);
   void CaptureNextFrame();
 
   base::Closure capture_callback_;
   bool paused_ = false;
   bool key_frame_request_ = false;
 
   base::TimeTicks last_capture_started_time_;
 
   LeakyBucket pacing_bucket_;
 
+  EncoderBitrateFilter encoder_bitrate_;
+
   // Set to true when a frame is being captured or encoded.
   bool frame_pending_ = false;
 
   base::TimeDelta rtt_estimate_;
 
   // Set to true when encoding unchanged frames for top-off.
   bool top_off_is_active_ = false;
 
   // Accumulator for capture and encoder delay history.
   RunningSamples frame_processing_delay_us_;
 
   // Accumulator for updated region area in the previously encoded frames.
   RunningSamples updated_region_area_;
 
   base::OneShotTimer capture_timer_;
 
   base::ThreadChecker thread_checker_;
   base::WeakPtrFactory<WebrtcFrameSchedulerSimple> weak_factory_;
 };
 
 }  // namespace protocol
 }  // namespace remoting
 
 #endif  // REMOTING_PROTOCOL_WEBRTC_FRAME_SCHEDULER_SIMPLE_H_