Reland of Make RTX pt/apt reconfigurable by calling WebRtcVideoChannel2::SetRecvParameters.

webrtc/video/rtp_stream_receiver.cc

 /*
  *  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 134 matching lines @@
     EnableReceiveRtpHeaderExtension(config_.rtp.extensions[i].uri,
                                     config_.rtp.extensions[i].id);
   }
 
   static const int kMaxPacketAgeToNack = 450;
   const int max_reordering_threshold = (config_.rtp.nack.rtp_history_ms > 0)
                                            ? kMaxPacketAgeToNack
                                            : kDefaultMaxReorderingThreshold;
   rtp_receive_statistics_->SetMaxReorderingThreshold(max_reordering_threshold);
 
-  // TODO(pbos): Support multiple RTX, per video payload.
-  for (const auto& kv : config_.rtp.rtx) {
-    RTC_DCHECK(kv.second.ssrc != 0);
-    RTC_DCHECK(kv.second.payload_type != 0);
+  if (config_.rtp.rtx_ssrc) {
+    rtp_payload_registry_.SetRtxSsrc(config_.rtp.rtx_ssrc);
 
-    rtp_payload_registry_.SetRtxSsrc(kv.second.ssrc);
-    rtp_payload_registry_.SetRtxPayloadType(kv.second.payload_type,
-                                            kv.first);
+    for (const auto& kv : config_.rtp.rtx_payload_types) {
+      RTC_DCHECK(kv.second != 0);
+      rtp_payload_registry_.SetRtxPayloadType(kv.second, kv.first);
+    }
   }
 
   if (IsUlpfecEnabled()) {
     VideoCodec ulpfec_codec = {};
     ulpfec_codec.codecType = kVideoCodecULPFEC;
     strncpy(ulpfec_codec.plName, "ulpfec", sizeof(ulpfec_codec.plName));
     ulpfec_codec.plType = config_.rtp.ulpfec.ulpfec_payload_type;
     RTC_CHECK(AddReceiveCodec(ulpfec_codec));
   }
 
@@ skipping 503 matching lines @@
     return;
 
   if (!sprop_decoder.DecodeSprop(sprop_base64_it->second.c_str()))
     return;
 
   tracker_.InsertSpsPpsNalus(sprop_decoder.sps_nalu(),
                              sprop_decoder.pps_nalu());
 }
 
 }  // namespace webrtc