Fix issue where the first audio packets significantly impacts initial BWE negatively.

webrtc/modules/remote_bitrate_estimator/include/remote_bitrate_estimator.h

 /*
  *  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 98 matching lines @@
   // Returns true if a valid estimate exists and sets |bitrate_bps| to the
   // estimated payload bitrate in bits per second. |ssrcs| is the list of ssrcs
   // currently being received and of which the bitrate estimate is based upon.
   virtual bool LatestEstimate(std::vector<unsigned int>* ssrcs,
                               unsigned int* bitrate_bps) const = 0;
 
   // Returns true if the statistics are available.
   virtual bool GetStats(ReceiveBandwidthEstimatorStats* output) const = 0;
 
  protected:
-  static const int64_t kProcessIntervalMs = 1000;
+  static const int64_t kProcessIntervalMs = 500;
   static const int64_t kStreamTimeOutMs = 2000;
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_REMOTE_BITRATE_ESTIMATOR_INCLUDE_REMOTE_BITRATE_ESTIMATOR_H_