Centralize deactivation of Unequal Protection.

webrtc/modules/rtp_rtcp/source/producer_fec.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 81 matching lines @@
   return data_.get();
 }
 
 size_t RedPacket::length() const {
   return length_;
 }
 
 ProducerFec::ProducerFec()
     : fec_(ForwardErrorCorrection::CreateUlpfec()),
       num_protected_frames_(0),
-      num_important_packets_(0),
       min_num_media_packets_(1) {
   memset(&params_, 0, sizeof(params_));
   memset(&new_params_, 0, sizeof(new_params_));
 }
 
 ProducerFec::~ProducerFec() = default;
 
 std::unique_ptr<RedPacket> ProducerFec::BuildRedPacket(
     const uint8_t* data_buffer,
     size_t payload_length,
     size_t rtp_header_length,
     int red_payload_type) {
   std::unique_ptr<RedPacket> red_packet(new RedPacket(
       payload_length + kRedForFecHeaderLength + rtp_header_length));
   int payload_type = data_buffer[1] & 0x7f;
   red_packet->CreateHeader(data_buffer, rtp_header_length, red_payload_type,
                            payload_type);
   red_packet->AssignPayload(data_buffer + rtp_header_length, payload_length);
   return red_packet;
 }
 
-void ProducerFec::SetFecParameters(const FecProtectionParams* params,
-                                   int num_important_packets) {
-  // Number of important packets (i.e. number of packets receiving additional
-  // protection in 'unequal protection mode') cannot exceed kMaxMediaPackets.
+void ProducerFec::SetFecParameters(const FecProtectionParams* params) {
   RTC_DCHECK_GE(params->fec_rate, 0);
   RTC_DCHECK_LE(params->fec_rate, 255);
-  if (num_important_packets > static_cast<int>(kUlpfecMaxMediaPackets)) {
-    num_important_packets = kUlpfecMaxMediaPackets;
-  }
   // Store the new params and apply them for the next set of FEC packets being
   // produced.
   new_params_ = *params;
-  num_important_packets_ = num_important_packets;
   if (params->fec_rate > kHighProtectionThreshold) {
     min_num_media_packets_ = kMinMediaPackets;
   } else {
     min_num_media_packets_ = 1;
   }
 }
 
 int ProducerFec::AddRtpPacketAndGenerateFec(const uint8_t* data_buffer,
                                             size_t payload_length,
                                             size_t rtp_header_length) {
@@ skipping 15 matching lines @@
     ++num_protected_frames_;
     complete_frame = true;
   }
   // Produce FEC over at most |params_.max_fec_frames| frames, or as soon as:
   // (1) the excess overhead (actual overhead - requested/target overhead) is
   // less than |kMaxExcessOverhead|, and
   // (2) at least |min_num_media_packets_| media packets is reached.
   if (complete_frame &&
       (num_protected_frames_ == params_.max_fec_frames ||
        (ExcessOverheadBelowMax() && MinimumMediaPacketsReached()))) {
-    RTC_DCHECK_LE(num_important_packets_,
-                  static_cast<int>(kUlpfecMaxMediaPackets));
-    // TODO(pbos): Consider whether unequal protection should be enabled or not,
-    // it is currently always disabled.
-    //
-    // Since unequal protection is disabled, the value of
-    // |num_important_packets_| has no importance when calling GenerateFec().
+    // We are not using Unequal Protection feature of the parity erasure code.
+    constexpr int kNumImportantPackets = 0;
     constexpr bool kUseUnequalProtection = false;
     int ret = fec_->EncodeFec(media_packets_, params_.fec_rate,
-                              num_important_packets_, kUseUnequalProtection,
+                              kNumImportantPackets, kUseUnequalProtection,
                               params_.fec_mask_type, &generated_fec_packets_);
     if (generated_fec_packets_.empty()) {
       ResetState();
     }
     return ret;
   }
   return 0;
 }
 
 bool ProducerFec::ExcessOverheadBelowMax() const {
@@ skipping 63 matching lines @@
   return (num_fec_packets << 8) / media_packets_.size();
 }
 
 void ProducerFec::ResetState() {
   media_packets_.clear();
   generated_fec_packets_.clear();
   num_protected_frames_ = 0;
 }
 
 }  // namespace webrtc