Deactivated the intelligibility enhancement functionality by default

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 615 matching lines @@
 #endif
 
 #if defined(WEBRTC_IOS) || defined(ANDROID)
   // Set the AGC mode for iOS as well despite disabling it above, to avoid
   // unsupported configuration errors from webrtc.
   agc_mode = webrtc::kAgcFixedDigital;
   options.typing_detection = rtc::Optional<bool>(false);
   options.experimental_agc = rtc::Optional<bool>(false);
   options.extended_filter_aec = rtc::Optional<bool>(false);
   options.experimental_ns = rtc::Optional<bool>(false);
+
+  // Hardcode the intelligibility enhancer to be off.
+  options.intelligibility_enhancer = rtc::Optional<bool>(false);
 #endif
 
   // Delay Agnostic AEC automatically turns on EC if not set except on iOS
   // where the feature is not supported.
   bool use_delay_agnostic_aec = false;
 #if !defined(WEBRTC_IOS)
   if (options.delay_agnostic_aec) {
     use_delay_agnostic_aec = *options.delay_agnostic_aec;
     if (use_delay_agnostic_aec) {
       options.echo_cancellation = rtc::Optional<bool>(true);
@@ skipping 2004 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