Generalize FEC header formatting. (pt. 4)

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 75 matching lines @@
 
 uint8_t* RedPacket::data() const {
   return data_.get();
 }
 
 size_t RedPacket::length() const {
   return length_;
 }
 
 ProducerFec::ProducerFec()
-    : num_protected_frames_(0),
+    : fec_(ForwardErrorCorrection::CreateUlpfec()),
+      num_protected_frames_(0),
       num_important_packets_(0),
-      min_num_media_packets_(1)  {
+      min_num_media_packets_(1) {
   memset(&params_, 0, sizeof(params_));
   memset(&new_params_, 0, sizeof(new_params_));
 }
 
 ProducerFec::~ProducerFec() {
   DeleteMediaPackets();
 }
 
 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.
   RTC_DCHECK_GE(params->fec_rate, 0);
   RTC_DCHECK_LE(params->fec_rate, 255);
-  if (num_important_packets >
-      static_cast<int>(ForwardErrorCorrection::kMaxMediaPackets)) {
-    num_important_packets = ForwardErrorCorrection::kMaxMediaPackets;
+  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) {
   RTC_DCHECK(generated_fec_packets_.empty());
   if (media_packets_.empty()) {
     params_ = new_params_;
   }
   bool complete_frame = false;
   const bool marker_bit = (data_buffer[1] & kRtpMarkerBitMask) ? true : false;
-  if (media_packets_.size() < ForwardErrorCorrection::kMaxMediaPackets) {
-    // Generic FEC can only protect up to |kMaxMediaPackets| packets.
+  if (media_packets_.size() < kUlpfecMaxMediaPackets) {
+    // Generic FEC can only protect up to |kUlpfecMaxMediaPackets| packets.
     std::unique_ptr<ForwardErrorCorrection::Packet> packet(
         new ForwardErrorCorrection::Packet());
     packet->length = payload_length + rtp_header_length;
     memcpy(packet->data, data_buffer, packet->length);
     media_packets_.push_back(std::move(packet));
   }
   if (marker_bit) {
     ++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>(ForwardErrorCorrection::kMaxMediaPackets));
+                  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().
     constexpr bool kUseUnequalProtection = false;
-    int ret = fec_.EncodeFec(media_packets_, params_.fec_rate,
-                             num_important_packets_, kUseUnequalProtection,
-                             params_.fec_mask_type, &generated_fec_packets_);
+    int ret = fec_->EncodeFec(media_packets_, params_.fec_rate,
+                              num_important_packets_, kUseUnequalProtection,
+                              params_.fec_mask_type, &generated_fec_packets_);
     if (generated_fec_packets_.empty()) {
       num_protected_frames_ = 0;
       DeleteMediaPackets();
     }
     return ret;
   }
   return 0;
 }
 
 bool ProducerFec::ExcessOverheadBelowMax() const {
@@ skipping 15 matching lines @@
 
 bool ProducerFec::FecAvailable() const {
   return !generated_fec_packets_.empty();
 }
 
 size_t ProducerFec::NumAvailableFecPackets() const {
   return generated_fec_packets_.size();
 }
 
 size_t ProducerFec::MaxPacketOverhead() const {
-  return fec_.MaxPacketOverhead();
+  return fec_->MaxPacketOverhead();
 }
 
 std::vector<std::unique_ptr<RedPacket>> ProducerFec::GetFecPacketsAsRed(
     int red_payload_type,
     int ulpfec_payload_type,
     uint16_t first_seq_num,
     size_t rtp_header_length) {
   std::vector<std::unique_ptr<RedPacket>> red_packets;
   red_packets.reserve(generated_fec_packets_.size());
   RTC_DCHECK(!media_packets_.empty());
   ForwardErrorCorrection::Packet* last_media_packet =
       media_packets_.back().get();
   uint16_t seq_num = first_seq_num;
   for (const auto& fec_packet : generated_fec_packets_) {
     // Wrap FEC packet (including FEC headers) in a RED packet. Since the
     // FEC packets in |generated_fec_packets_| don't have RTP headers, we
     // reuse the header from the last media packet.
     std::unique_ptr<RedPacket> red_packet(new RedPacket(
         fec_packet->length + kRedForFecHeaderLength + rtp_header_length));
     red_packet->CreateHeader(last_media_packet->data, rtp_header_length,
                              red_payload_type, ulpfec_payload_type);
     red_packet->SetSeqNum(seq_num++);
     red_packet->ClearMarkerBit();
     red_packet->AssignPayload(fec_packet->data, fec_packet->length);
-
     red_packets.push_back(std::move(red_packet));
   }
-
   // Reset state.
   DeleteMediaPackets();
   generated_fec_packets_.clear();
   num_protected_frames_ = 0;
-
   return red_packets;
 }
 
 int ProducerFec::Overhead() const {
   // Overhead is defined as relative to the number of media packets, and not
   // relative to total number of packets. This definition is inherited from the
   // protection factor produced by video_coding module and how the FEC
   // generation is implemented.
   RTC_DCHECK(!media_packets_.empty());
   int num_fec_packets =
-      fec_.NumFecPackets(media_packets_.size(), params_.fec_rate);
+      fec_->NumFecPackets(media_packets_.size(), params_.fec_rate);
   // Return the overhead in Q8.
   return (num_fec_packets << 8) / media_packets_.size();
 }
 
 void ProducerFec::DeleteMediaPackets() {
   media_packets_.clear();
 }
 
 }  // namespace webrtc