Update encoder settings periodically, not only on new bandwidth estimate

webrtc/modules/video_coding/main/source/media_optimization.cc

 /*
  *  Copyright (c) 2012 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.
  */
 
@@ skipping 613 matching lines @@
   for (num = 1; num < (kFrameCountHistorySize - 1); ++num) {
     if (incoming_frame_times_[num] <= 0 ||
         // don't use data older than 2 s
         now - incoming_frame_times_[num] > kFrameHistoryWinMs) {
       break;
     } else {
       nr_of_frames++;
     }
   }
   if (num > 1) {
-    const int64_t diff = now - incoming_frame_times_[num - 1];
-    incoming_frame_rate_ = 1.0;
+    const int64_t diff =
+        incoming_frame_times_[0] - incoming_frame_times_[num - 1];
+    incoming_frame_rate_ = 0.0;  // No frame rate estimate available.
     if (diff > 0) {
       incoming_frame_rate_ = nr_of_frames * 1000.0f / static_cast<float>(diff);
     }
   }
 }
 
 void MediaOptimization::CheckSuspendConditions() {
   // Check conditions for SuspendBelowMinBitrate. |target_bit_rate_| is in bps.
   if (suspension_enabled_) {
     if (!video_suspended_) {
       // Check if we just went below the threshold.
       if (target_bit_rate_ < suspension_threshold_bps_) {
         video_suspended_ = true;
       }
     } else {
       // Video is already suspended. Check if we just went over the threshold
       // with a margin.
       if (target_bit_rate_ >
           suspension_threshold_bps_ + suspension_window_bps_) {
         video_suspended_ = false;
       }
     }
   }
 }
 
 }  // namespace media_optimization
 }  // namespace webrtc