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 46 matching lines @@
 // On Windows systems which only support Wave Audio style default, uses either
 // -1 or 0 to select the default device.
 #ifdef WIN32
 const int kDefaultAudioDeviceId = -1;
 #elif !defined(WEBRTC_IOS)
 const int kDefaultAudioDeviceId = 0;
 #endif
 
 constexpr int kNackRtpHistoryMs = 5000;
 
+// Check to verify that the define for the intelligibility enhancer is properly
+// set.
+#if !defined(WEBRTC_INTELLIGIBILITY_ENHANCER) || \

[the sun, 2016/08/26 12:08:56]

Why not just
#if WEBRTC_INTELLIGIBILITY_ENHANCER
?
(unset defaults to 0)

[kjellander_webrtc, 2016/08/26 12:52:01]

I think there was a similar discussion for an AEC define and there was a good
reason for having it set to 0 or 1. I can't recall exactly why it was safer
though.

[peah-webrtc, 2016/08/26 13:09:43]

The reason was it is up to the build system to distribute the defines. And if
that is missed in some place, that will be a silent error as the define then
defaults to 0.

The construct here is not perfect either, but it at least requires the define to
be explicitly set.

In this case, I think nothing can go bad at runtime during this, but the code
may evolve and therefore I'd prefer to have it like this.

[peah-webrtc, 2016/08/26 13:09:43]

The reason behind that is that this is a define that spans several subunits in
the build system, and doing the check like this ensures that it is explicitly
defined everywhere. 

This is to avoid previous errors where the define was set to 1 in some places
but was not specified in other places without any warning thereof.

[the sun, 2016/08/26 13:17:48]

Does it have to be like that then? Could it be set up in one place in the build
files?

Even if you make sure it is set explicitly, it may still be set differently.

+    (WEBRTC_INTELLIGIBILITY_ENHANCER != 0 &&     \
+     WEBRTC_INTELLIGIBILITY_ENHANCER != 1)
+#error "Set WEBRTC_INTELLIGIBILITY_ENHANCER to either 0 or 1"
+#endif
+
 // Codec parameters for Opus.
 // draft-spittka-payload-rtp-opus-03
 
 // Recommended bitrates:
 // 8-12 kb/s for NB speech,
 // 16-20 kb/s for WB speech,
 // 28-40 kb/s for FB speech,
 // 48-64 kb/s for FB mono music, and
 // 64-128 kb/s for FB stereo music.
 // The current implementation applies the following values to mono signals,
@@ skipping 565 matching lines @@
   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);
       options.extended_filter_aec = rtc::Optional<bool>(true);
       ec_mode = webrtc::kEcConference;
     }
   }
 #endif
 
+#if (WEBRTC_INTELLIGIBILITY_ENHANCER == 0)
+  // Hardcode the intelligibility enhancer to be off.
+  options.intelligibility_enhancer = rtc::Optional<bool>(false);
+#endif
+
   webrtc::VoEAudioProcessing* voep = voe_wrapper_->processing();
 
   if (options.echo_cancellation) {
     // Check if platform supports built-in EC. Currently only supported on
     // Android and in combination with Java based audio layer.
     // TODO(henrika): investigate possibility to support built-in EC also
     // in combination with Open SL ES audio.
     const bool built_in_aec = adm()->BuiltInAECIsAvailable();
     if (built_in_aec) {
       // Built-in EC exists on this device and use_delay_agnostic_aec is not
@@ skipping 1988 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