Split FlexFEC field trial in two.

webrtc/media/engine/internalencoderfactory.cc

 /*
  *  Copyright (c) 2016 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.
  */
 
 #include "webrtc/media/engine/internalencoderfactory.h"
 
 #include <utility>
 
 #include "webrtc/modules/video_coding/codecs/h264/include/h264.h"
 #include "webrtc/modules/video_coding/codecs/vp8/include/vp8.h"
 #include "webrtc/modules/video_coding/codecs/vp9/include/vp9.h"
 #include "webrtc/system_wrappers/include/field_trial.h"
 
 namespace cricket {
 
 namespace {
 
-const char kFlexfecFieldTrialName[] = "WebRTC-FlexFEC-03";
-
-bool IsFlexfecFieldTrialEnabled() {
-  return webrtc::field_trial::IsEnabled(kFlexfecFieldTrialName);
+// If this field trial is enabled, the "flexfec-03" codec will be advertised
+// as being supported by the InternalEncoderFactory. This means that
+// "flexfec-03" will appear in the default local SDP, and we therefore need to
+// be ready to receive FlexFEC packets from the remote.
+bool IsFlexfecAdvertisedFieldTrialEnabled() {
+  return webrtc::field_trial::FindFullName("WebRTC-FlexFEC-03-Advertised") ==
+         "Enabled";
 }
 
 }  // namespace
 
 InternalEncoderFactory::InternalEncoderFactory() {
   supported_codecs_.push_back(cricket::VideoCodec(kVp8CodecName));
   if (webrtc::VP9Encoder::IsSupported())
     supported_codecs_.push_back(cricket::VideoCodec(kVp9CodecName));
   if (webrtc::H264Encoder::IsSupported()) {
     cricket::VideoCodec codec(kH264CodecName);
     // TODO(magjed): Move setting these parameters into webrtc::H264Encoder
     // instead.
     codec.SetParam(kH264FmtpProfileLevelId,
                    kH264ProfileLevelConstrainedBaseline);
     codec.SetParam(kH264FmtpLevelAsymmetryAllowed, "1");
     supported_codecs_.push_back(std::move(codec));
   }
 
   supported_codecs_.push_back(cricket::VideoCodec(kRedCodecName));
   supported_codecs_.push_back(cricket::VideoCodec(kUlpfecCodecName));
 
-  if (IsFlexfecFieldTrialEnabled()) {
+  if (IsFlexfecAdvertisedFieldTrialEnabled()) {
     cricket::VideoCodec flexfec_codec(kFlexfecCodecName);
     // This value is currently arbitrarily set to 10 seconds. (The unit
     // is microseconds.) This parameter MUST be present in the SDP, but
     // we never use the actual value anywhere in our code however.
     // TODO(brandtr): Consider honouring this value in the sender and receiver.
     flexfec_codec.SetParam(kFlexfecFmtpRepairWindow, "10000000");
     flexfec_codec.AddFeedbackParam(
         FeedbackParam(kRtcpFbParamTransportCc, kParamValueEmpty));
     flexfec_codec.AddFeedbackParam(
         FeedbackParam(kRtcpFbParamRemb, kParamValueEmpty));
@@ skipping 25 matching lines @@
 InternalEncoderFactory::supported_codecs() const {
   return supported_codecs_;
 }
 
 void InternalEncoderFactory::DestroyVideoEncoder(
     webrtc::VideoEncoder* encoder) {
   delete encoder;
 }
 
 }  // namespace cricket