Simplify public interface of ProducerFec.

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.
  */
 
 #include "webrtc/modules/rtp_rtcp/source/producer_fec.h"
 
 #include <memory>
 #include <utility>
 
 #include "webrtc/base/basictypes.h"
 #include "webrtc/base/checks.h"
 #include "webrtc/modules/rtp_rtcp/source/byte_io.h"
 #include "webrtc/modules/rtp_rtcp/source/forward_error_correction.h"
 #include "webrtc/modules/rtp_rtcp/source/rtp_utility.h"
 
 namespace webrtc {
 
+namespace {
+
 constexpr size_t kRedForFecHeaderLength = 1;
 
 // This controls the maximum amount of excess overhead (actual - target)
 // allowed in order to trigger EncodeFec(), before |params_.max_fec_frames|
 // is reached. Overhead here is defined as relative to number of media packets.
 constexpr int kMaxExcessOverhead = 50;  // Q8.
 
 // This is the minimum number of media packets required (above some protection
 // level) in order to trigger EncodeFec(), before |params_.max_fec_frames| is
 // reached.
 constexpr size_t kMinMediaPackets = 4;
 
 // Threshold on the received FEC protection level, above which we enforce at
 // least |kMinMediaPackets| packets for the FEC code. Below this
 // threshold |kMinMediaPackets| is set to default value of 1.
 //
 // The range is between 0 and 255, where 255 corresponds to 100% overhead
 // (relative to the number of protected media packets).
 constexpr uint8_t kHighProtectionThreshold = 80;
 
 // This threshold is used to adapt the |kMinMediaPackets| threshold, based
 // on the average number of packets per frame seen so far. When there are few
 // packets per frame (as given by this threshold), at least
 // |kMinMediaPackets| + 1 packets are sent to the FEC code.
 constexpr float kMinMediaPacketsAdaptationThreshold = 2.0f;
 
+}  // namespace
+
 RedPacket::RedPacket(size_t length)
     : data_(new uint8_t[length]),
       length_(length),
       header_length_(0) {
 }
 
 void RedPacket::CreateHeader(const uint8_t* rtp_header,
                              size_t header_length,
                              int red_payload_type,
                              int payload_type) {
@@ skipping 34 matching lines @@
 
 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() {
-  DeleteMediaPackets();
-}
+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,
@@ skipping 55 matching lines @@
     // 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_);
     if (generated_fec_packets_.empty()) {
-      num_protected_frames_ = 0;
-      DeleteMediaPackets();
+      ResetState();
     }
     return ret;
   }
   return 0;
 }
 
 bool ProducerFec::ExcessOverheadBelowMax() const {
   return ((Overhead() - params_.fec_rate) < kMaxExcessOverhead);
 }
 
@@ skipping 15 matching lines @@
 }
 
 size_t ProducerFec::NumAvailableFecPackets() const {
   return generated_fec_packets_.size();
 }
 
 size_t ProducerFec::MaxPacketOverhead() const {
   return fec_->MaxPacketOverhead();
 }
 
-std::vector<std::unique_ptr<RedPacket>> ProducerFec::GetFecPacketsAsRed(
+std::vector<std::unique_ptr<RedPacket>> ProducerFec::GetUlpfecPacketsAsRed(
     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;
+
+  ResetState();
+
   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);
   // Return the overhead in Q8.
   return (num_fec_packets << 8) / media_packets_.size();
 }
 
-void ProducerFec::DeleteMediaPackets() {
+void ProducerFec::ResetState() {
   media_packets_.clear();
+  generated_fec_packets_.clear();
+  num_protected_frames_ = 0;
 }
 
 }  // namespace webrtc