Make sure min and max bitrate is always set for audio.

webrtc/media/engine/webrtcvoiceengine.cc

 /*
  *  Copyright (c) 2004 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 1437 matching lines @@
 
   void RecreateAudioSendStream() {
     RTC_DCHECK(worker_thread_checker_.CalledOnValidThread());
     if (stream_) {
       call_->DestroyAudioSendStream(stream_);
       stream_ = nullptr;
     }
     RTC_DCHECK(!stream_);
     if (webrtc::field_trial::FindFullName("WebRTC-Audio-SendSideBwe") ==
         "Enabled") {
+      config_.min_bitrate_bps = kOpusMinBitrateBps;
+      config_.max_bitrate_bps = kOpusBitrateFbBps;
       // TODO(mflodman): Keep testing this and set proper values.
       // Note: This is an early experiment currently only supported by Opus.
       if (webrtc::field_trial::FindFullName(
               "WebRTC-SendSideBwe-WithOverhead") == "Enabled") {
         auto packet_sizes_ms = WebRtcVoiceCodecs::GetPacketSizesMs(
             config_.send_codec_spec.codec_inst);
         if (!packet_sizes_ms.empty()) {
           int max_packet_size_ms =
               *std::max_element(packet_sizes_ms.begin(), packet_sizes_ms.end());
           int min_packet_size_ms =
@@ skipping 12 matching lines @@
 
           int min_overhead_bps =
               kOverheadPerPacket * 8 * 1000 / max_packet_size_ms;
 
           int max_overhead_bps =
               kOverheadPerPacket * 8 * 1000 / min_packet_size_ms;
 
           config_.min_bitrate_bps = kOpusMinBitrateBps + min_overhead_bps;
           config_.max_bitrate_bps = kOpusBitrateFbBps + max_overhead_bps;
         }
-      } else {
-        config_.min_bitrate_bps = kOpusMinBitrateBps;

[minyue-webrtc, 2017/01/24 14:22:00]

Then it should be outside if(webrtc::field_trial::FindFullName...) rather than
in else-branch.

But you know what, I think it might even need to just remove the outer if
(SendSideBwe).

WithOverhead can be set without SendSideBwe, right?

[stefan-webrtc, 2017/01/24 14:48:03]

I don't follow, I moved it from the else branch to outside line 1462. Do you
mean that I should move it to line 1456? I could, but it doesn't have any effect
without BWE.
It can, but I'm not aware of any plans to do so, and I don't think it would have
any effect?

-        config_.max_bitrate_bps = kOpusBitrateFbBps;
       }
     }
     stream_ = call_->CreateAudioSendStream(config_);
     RTC_CHECK(stream_);
     UpdateSendState();
   }
 
   rtc::ThreadChecker worker_thread_checker_;
   rtc::RaceChecker audio_capture_race_checker_;
   webrtc::AudioTransport* const voe_audio_transport_ = nullptr;
@@ skipping 1202 matching lines @@
   RTC_DCHECK(worker_thread_checker_.CalledOnValidThread());
   const auto it = send_streams_.find(ssrc);
   if (it != send_streams_.end()) {
     return it->second->channel();
   }
   return -1;
 }
 }  // namespace cricket
 
 #endif  // HAVE_WEBRTC_VOICE