Only compare sequence numbers from the same SSRC in ForwardErrorCorrection.

webrtc/modules/rtp_rtcp/source/ulpfec_receiver_impl.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 72 matching lines @@
   }
 
   // Remove RED header of incoming packet and store as a virtual RTP packet.
   std::unique_ptr<ForwardErrorCorrection::ReceivedPacket> received_packet(
       new ForwardErrorCorrection::ReceivedPacket());
   received_packet->pkt = new ForwardErrorCorrection::Packet();
 
   // Get payload type from RED header and sequence number from RTP header.
   uint8_t payload_type = incoming_rtp_packet[header.headerLength] & 0x7f;
   received_packet->is_fec = payload_type == ulpfec_payload_type;
+  received_packet->ssrc = header.ssrc;
   received_packet->seq_num = header.sequenceNumber;
 
   uint16_t block_length = 0;
   if (incoming_rtp_packet[header.headerLength] & 0x80) {
     // f bit set in RED header, i.e. there are more than one RED header blocks.
     red_header_length = 4;
     if (payload_data_length < red_header_length + 1u) {
       LOG(LS_WARNING) << "Corrupt/truncated FEC packet.";
       return -1;
     }
@@ skipping 45 matching lines @@
     // Copy payload data.
     memcpy(received_packet->pkt->data + header.headerLength,
            incoming_rtp_packet + header.headerLength + red_header_length,
            block_length);
     received_packet->pkt->length = block_length;
 
     second_received_packet.reset(new ForwardErrorCorrection::ReceivedPacket);
     second_received_packet->pkt = new ForwardErrorCorrection::Packet;
 
     second_received_packet->is_fec = true;
+    second_received_packet->ssrc = header.ssrc;
     second_received_packet->seq_num = header.sequenceNumber;
     ++packet_counter_.num_fec_packets;
 
     // Copy FEC payload data.
     memcpy(second_received_packet->pkt->data,
            incoming_rtp_packet + header.headerLength + red_header_length +
                block_length,
            payload_data_length - red_header_length - block_length);
 
     second_received_packet->pkt->length =
@@ skipping 70 matching lines @@
       return -1;
     }
     crit_sect_.Enter();
     recovered_packet->returned = true;
   }
   crit_sect_.Leave();
   return 0;
 }
 
 }  // namespace webrtc