Generalize FEC unit tests and rename GenerateFec.

- Rename GenerateFec -> EncodeFec in ForwardErrorCorrection. This naming
  is more consistent with DecodeFec.
- Add appropriate using directives, to reduce clutter in tests.
- Move ConstructMediaPackets to fec_test_helper.{h,cc}. This will help
  future tests of ULPFEC/FlexFEC header formatters.
- Generalize tests in rtp_fec_unittest.cc to typed tests. This will help
  testing ForwardErrorCorrection with both ULPFEC and FlexFEC.

This CL should not impact functionality or performance.

BUG=webrtc:5654

Review-Url: https://codereview.webrtc.org/2267393002
Cr-Commit-Position: refs/heads/master@{#14314}

webrtc/modules/rtp_rtcp/source/fec_receiver_unittest.cc

@@ -22,46 +22,48 @@
 #include "webrtc/modules/rtp_rtcp/source/fec_test_helper.h"
 #include "webrtc/modules/rtp_rtcp/source/forward_error_correction.h"
 
+namespace webrtc {
+
+namespace {
+constexpr uint8_t kFecPayloadType = 96;
+}  // namespace
+
 using ::testing::_;
 using ::testing::Args;
 using ::testing::ElementsAreArray;
 using ::testing::Return;
-using Packet = webrtc::ForwardErrorCorrection::Packet;
 
-namespace webrtc {
+using ::webrtc::test::fec::FrameGenerator;
+using Packet = ::webrtc::ForwardErrorCorrection::Packet;
+using ::webrtc::test::fec::RawRtpPacket;
 
 class ReceiverFecTest : public ::testing::Test {
  protected:
-  virtual void SetUp() {
+  ReceiverFecTest() : receiver_fec_(FecReceiver::Create(&rtp_data_callback_)) {}
-    fec_.reset(new ForwardErrorCorrection());
-    receiver_fec_.reset(FecReceiver::Create(&rtp_data_callback_));
-    generator_.reset(new FrameGenerator());
-  }
 
-  void GenerateFec(ForwardErrorCorrection::PacketList* media_packets,
+  void EncodeFec(ForwardErrorCorrection::PacketList* media_packets,
                  std::list<ForwardErrorCorrection::Packet*>* fec_packets,
                  unsigned int num_fec_packets) {
     uint8_t protection_factor = num_fec_packets * 255 / media_packets->size();
-    EXPECT_EQ(0, fec_->GenerateFec(*media_packets, protection_factor,
+    EXPECT_EQ(0, fec_.EncodeFec(*media_packets, protection_factor, 0, false,
-                                   0, false, kFecMaskBursty, fec_packets));
+                                kFecMaskBursty, fec_packets));
     ASSERT_EQ(num_fec_packets, fec_packets->size());
   }
 
   void GenerateFrame(int num_media_packets,
                      int frame_offset,
-                     std::list<test::RawRtpPacket*>* media_rtp_packets,
+                     std::list<RawRtpPacket*>* media_rtp_packets,
                      ForwardErrorCorrection::PacketList* media_packets) {
-    generator_->NewFrame(num_media_packets);
+    generator_.NewFrame(num_media_packets);
     for (int i = 0; i < num_media_packets; ++i) {
-      std::unique_ptr<test::RawRtpPacket> next_packet(
+      std::unique_ptr<RawRtpPacket> next_packet(
-        generator_->NextPacket(frame_offset + i, kRtpHeaderSize + 10));
+          generator_.NextPacket(frame_offset + i, kRtpHeaderSize + 10));
       media_rtp_packets->push_back(next_packet.get());
       media_packets->push_back(std::move(next_packet));
     }
   }
 
-  void VerifyReconstructedMediaPacket(const test::RawRtpPacket* packet,
+  void VerifyReconstructedMediaPacket(const RawRtpPacket* packet, int times) {
-                                      int times) {
     // Verify that the content of the reconstructed packet is equal to the
     // content of |packet|, and that the same content is received |times| number
     // of times in a row.
@@ -71,17 +73,17 @@ class ReceiverFecTest : public ::testing::Test {
         .Times(times).WillRepeatedly(Return(true));
   }
 
-  void BuildAndAddRedMediaPacket(test::RawRtpPacket* packet) {
+  void BuildAndAddRedMediaPacket(RawRtpPacket* packet) {
-    std::unique_ptr<test::RawRtpPacket> red_packet(
+    std::unique_ptr<RawRtpPacket> red_packet(
-        generator_->BuildMediaRedPacket(packet));
+        generator_.BuildMediaRedPacket(packet));
     EXPECT_EQ(0, receiver_fec_->AddReceivedRedPacket(
                      red_packet->header.header, red_packet->data,
                      red_packet->length, kFecPayloadType));
   }
 
   void BuildAndAddRedFecPacket(Packet* packet) {
-    std::unique_ptr<test::RawRtpPacket> red_packet(
+    std::unique_ptr<RawRtpPacket> red_packet(
-        generator_->BuildFecRedPacket(packet));
+        generator_.BuildFecRedPacket(packet));
     EXPECT_EQ(0, receiver_fec_->AddReceivedRedPacket(
                      red_packet->header.header, red_packet->data,
                      red_packet->length, kFecPayloadType));
@@ -93,18 +95,18 @@ class ReceiverFecTest : public ::testing::Test {
                                       uint8_t ulpfec_payload_type);
 
   MockRtpData rtp_data_callback_;
-  std::unique_ptr<ForwardErrorCorrection> fec_;
+  ForwardErrorCorrection fec_;
   std::unique_ptr<FecReceiver> receiver_fec_;
-  std::unique_ptr<FrameGenerator> generator_;
+  FrameGenerator generator_;
 };
 
 TEST_F(ReceiverFecTest, TwoMediaOneFec) {
   const unsigned int kNumFecPackets = 1u;
-  std::list<test::RawRtpPacket*> media_rtp_packets;
+  std::list<RawRtpPacket*> media_rtp_packets;
   ForwardErrorCorrection::PacketList media_packets;
   GenerateFrame(2, 0, &media_rtp_packets, &media_packets);
   std::list<ForwardErrorCorrection::Packet*> fec_packets;
-  GenerateFec(&media_packets, &fec_packets, kNumFecPackets);
+  EncodeFec(&media_packets, &fec_packets, kNumFecPackets);
 
   // Recovery
   auto it = media_rtp_packets.begin();
@@ -129,11 +131,11 @@ void ReceiverFecTest::InjectGarbagePacketLength(size_t fec_garbage_offset) {
       .WillRepeatedly(Return(true));
 
   const unsigned int kNumFecPackets = 1u;
-  std::list<test::RawRtpPacket*> media_rtp_packets;
+  std::list<RawRtpPacket*> media_rtp_packets;
   ForwardErrorCorrection::PacketList media_packets;
   GenerateFrame(2, 0, &media_rtp_packets, &media_packets);
   std::list<ForwardErrorCorrection::Packet*> fec_packets;
-  GenerateFec(&media_packets, &fec_packets, kNumFecPackets);
+  EncodeFec(&media_packets, &fec_packets, kNumFecPackets);
   ByteWriter<uint16_t>::WriteBigEndian(
       &fec_packets.front()->data[fec_garbage_offset], 0x4711);
 
@@ -162,11 +164,11 @@ TEST_F(ReceiverFecTest, InjectGarbageFecLevelHeaderProtectionLength) {
 
 TEST_F(ReceiverFecTest, TwoMediaTwoFec) {
   const unsigned int kNumFecPackets = 2u;
-  std::list<test::RawRtpPacket*> media_rtp_packets;
+  std::list<RawRtpPacket*> media_rtp_packets;
   ForwardErrorCorrection::PacketList media_packets;
   GenerateFrame(2, 0, &media_rtp_packets, &media_packets);
   std::list<ForwardErrorCorrection::Packet*> fec_packets;
-  GenerateFec(&media_packets, &fec_packets, kNumFecPackets);
+  EncodeFec(&media_packets, &fec_packets, kNumFecPackets);
 
   // Recovery
   // Drop both media packets.
@@ -184,12 +186,12 @@ TEST_F(ReceiverFecTest, TwoMediaTwoFec) {
 
 TEST_F(ReceiverFecTest, TwoFramesOneFec) {
   const unsigned int kNumFecPackets = 1u;
-  std::list<test::RawRtpPacket*> media_rtp_packets;
+  std::list<RawRtpPacket*> media_rtp_packets;
   ForwardErrorCorrection::PacketList media_packets;
   GenerateFrame(1, 0, &media_rtp_packets, &media_packets);
   GenerateFrame(1, 1, &media_rtp_packets, &media_packets);
   std::list<ForwardErrorCorrection::Packet*> fec_packets;
-  GenerateFec(&media_packets, &fec_packets, kNumFecPackets);
+  EncodeFec(&media_packets, &fec_packets, kNumFecPackets);
 
   // Recovery
   auto it = media_rtp_packets.begin();
@@ -205,13 +207,13 @@ TEST_F(ReceiverFecTest, TwoFramesOneFec) {
 
 TEST_F(ReceiverFecTest, OneCompleteOneUnrecoverableFrame) {
   const unsigned int kNumFecPackets = 1u;
-  std::list<test::RawRtpPacket*> media_rtp_packets;
+  std::list<RawRtpPacket*> media_rtp_packets;
   ForwardErrorCorrection::PacketList media_packets;
   GenerateFrame(1, 0, &media_rtp_packets, &media_packets);
   GenerateFrame(2, 1, &media_rtp_packets, &media_packets);
 
   std::list<ForwardErrorCorrection::Packet*> fec_packets;
-  GenerateFec(&media_packets, &fec_packets, kNumFecPackets);
+  EncodeFec(&media_packets, &fec_packets, kNumFecPackets);
 
   // Recovery
   auto it = media_rtp_packets.begin();
@@ -227,13 +229,13 @@ TEST_F(ReceiverFecTest, OneCompleteOneUnrecoverableFrame) {
 TEST_F(ReceiverFecTest, MaxFramesOneFec) {
   const unsigned int kNumFecPackets = 1u;
   const unsigned int kNumMediaPackets = 48u;
-  std::list<test::RawRtpPacket*> media_rtp_packets;
+  std::list<RawRtpPacket*> media_rtp_packets;
   ForwardErrorCorrection::PacketList media_packets;
   for (unsigned int i = 0; i < kNumMediaPackets; ++i) {
     GenerateFrame(1, i, &media_rtp_packets, &media_packets);
   }
   std::list<ForwardErrorCorrection::Packet*> fec_packets;
-  GenerateFec(&media_packets, &fec_packets, kNumFecPackets);
+  EncodeFec(&media_packets, &fec_packets, kNumFecPackets);
 
   // Recovery
   auto it = media_rtp_packets.begin();
@@ -252,15 +254,15 @@ TEST_F(ReceiverFecTest, MaxFramesOneFec) {
 TEST_F(ReceiverFecTest, TooManyFrames) {
   const unsigned int kNumFecPackets = 1u;
   const unsigned int kNumMediaPackets = 49u;
-  std::list<test::RawRtpPacket*> media_rtp_packets;
+  std::list<RawRtpPacket*> media_rtp_packets;
   ForwardErrorCorrection::PacketList media_packets;
   for (unsigned int i = 0; i < kNumMediaPackets; ++i) {
     GenerateFrame(1, i, &media_rtp_packets, &media_packets);
   }
   std::list<ForwardErrorCorrection::Packet*> fec_packets;
-  EXPECT_EQ(-1, fec_->GenerateFec(media_packets,
+  EXPECT_EQ(
-                                  kNumFecPackets * 255 / kNumMediaPackets, 0,
+      -1, fec_.EncodeFec(media_packets, kNumFecPackets * 255 / kNumMediaPackets,
-                                  false, kFecMaskBursty, &fec_packets));
+                         0, false, kFecMaskBursty, &fec_packets));
 }
 
 TEST_F(ReceiverFecTest, PacketNotDroppedTooEarly) {
@@ -269,12 +271,12 @@ TEST_F(ReceiverFecTest, PacketNotDroppedTooEarly) {
   Packet* delayed_fec = NULL;
   const unsigned int kNumFecPacketsBatch1 = 1u;
   const unsigned int kNumMediaPacketsBatch1 = 2u;
-  std::list<test::RawRtpPacket*> media_rtp_packets_batch1;
+  std::list<RawRtpPacket*> media_rtp_packets_batch1;
   ForwardErrorCorrection::PacketList media_packets_batch1;
   GenerateFrame(kNumMediaPacketsBatch1, 0, &media_rtp_packets_batch1,
                 &media_packets_batch1);
   std::list<ForwardErrorCorrection::Packet*> fec_packets;
-  GenerateFec(&media_packets_batch1, &fec_packets, kNumFecPacketsBatch1);
+  EncodeFec(&media_packets_batch1, &fec_packets, kNumFecPacketsBatch1);
 
   BuildAndAddRedMediaPacket(media_rtp_packets_batch1.front());
   EXPECT_CALL(rtp_data_callback_, OnRecoveredPacket(_, _))
@@ -284,7 +286,7 @@ TEST_F(ReceiverFecTest, PacketNotDroppedTooEarly) {
 
   // Fill the FEC decoder. No packets should be dropped.
   const unsigned int kNumMediaPacketsBatch2 = 46u;
-  std::list<test::RawRtpPacket*> media_rtp_packets_batch2;
+  std::list<RawRtpPacket*> media_rtp_packets_batch2;
   ForwardErrorCorrection::PacketList media_packets_batch2;
   for (unsigned int i = 0; i < kNumMediaPacketsBatch2; ++i) {
     GenerateFrame(1, i, &media_rtp_packets_batch2, &media_packets_batch2);
@@ -310,12 +312,12 @@ TEST_F(ReceiverFecTest, PacketDroppedWhenTooOld) {
   Packet* delayed_fec = NULL;
   const unsigned int kNumFecPacketsBatch1 = 1u;
   const unsigned int kNumMediaPacketsBatch1 = 2u;
-  std::list<test::RawRtpPacket*> media_rtp_packets_batch1;
+  std::list<RawRtpPacket*> media_rtp_packets_batch1;
   ForwardErrorCorrection::PacketList media_packets_batch1;
   GenerateFrame(kNumMediaPacketsBatch1, 0, &media_rtp_packets_batch1,
                 &media_packets_batch1);
   std::list<ForwardErrorCorrection::Packet*> fec_packets;
-  GenerateFec(&media_packets_batch1, &fec_packets, kNumFecPacketsBatch1);
+  EncodeFec(&media_packets_batch1, &fec_packets, kNumFecPacketsBatch1);
 
   BuildAndAddRedMediaPacket(media_rtp_packets_batch1.front());
   EXPECT_CALL(rtp_data_callback_, OnRecoveredPacket(_, _))
@@ -325,7 +327,7 @@ TEST_F(ReceiverFecTest, PacketDroppedWhenTooOld) {
 
   // Fill the FEC decoder and force the last packet to be dropped.
   const unsigned int kNumMediaPacketsBatch2 = 48u;
-  std::list<test::RawRtpPacket*> media_rtp_packets_batch2;
+  std::list<RawRtpPacket*> media_rtp_packets_batch2;
   ForwardErrorCorrection::PacketList media_packets_batch2;
   for (unsigned int i = 0; i < kNumMediaPacketsBatch2; ++i) {
     GenerateFrame(1, i, &media_rtp_packets_batch2, &media_packets_batch2);
@@ -350,14 +352,14 @@ TEST_F(ReceiverFecTest, OldFecPacketDropped) {
   // 49 frames with 2 media packets and one FEC packet. All media packets
   // missing.
   const unsigned int kNumMediaPackets = 49 * 2;
-  std::list<test::RawRtpPacket*> media_rtp_packets;
+  std::list<RawRtpPacket*> media_rtp_packets;
   ForwardErrorCorrection::PacketList media_packets;
   for (unsigned int i = 0; i < kNumMediaPackets / 2; ++i) {
-    std::list<test::RawRtpPacket*> frame_media_rtp_packets;
+    std::list<RawRtpPacket*> frame_media_rtp_packets;
     ForwardErrorCorrection::PacketList frame_media_packets;
     std::list<ForwardErrorCorrection::Packet*> fec_packets;
     GenerateFrame(2, 0, &frame_media_rtp_packets, &frame_media_packets);
-    GenerateFec(&frame_media_packets, &fec_packets, 1);
+    EncodeFec(&frame_media_packets, &fec_packets, 1);
     for (auto it = fec_packets.begin(); it != fec_packets.end(); ++it) {
       // Only FEC packets inserted. No packets recoverable at this time.
       BuildAndAddRedFecPacket(*it);

webrtc/modules/rtp_rtcp/source/fec_test_helper.cc

@@ -10,10 +10,21 @@
 
 #include "webrtc/modules/rtp_rtcp/source/fec_test_helper.h"
 
+#include <memory>
+#include <utility>
+
 #include "webrtc/modules/rtp_rtcp/source/byte_io.h"
 #include "webrtc/modules/rtp_rtcp/source/rtp_utility.h"
 
 namespace webrtc {
+namespace test {
+namespace fec {
+
+namespace {
+constexpr uint8_t kFecPayloadType = 96;
+constexpr uint8_t kRedPayloadType = 97;
+constexpr uint8_t kVp8PayloadType = 120;
+}  // namespace
 
 FrameGenerator::FrameGenerator()
     : num_packets_(0), seq_num_(0), timestamp_(0) {}
@@ -25,8 +36,8 @@ void FrameGenerator::NewFrame(int num_packets) {
 
 uint16_t FrameGenerator::NextSeqNum() { return ++seq_num_; }
 
-test::RawRtpPacket* FrameGenerator::NextPacket(int offset, size_t length) {
+RawRtpPacket* FrameGenerator::NextPacket(int offset, size_t length) {
-  test::RawRtpPacket* rtp_packet = new test::RawRtpPacket;
+  RawRtpPacket* rtp_packet = new RawRtpPacket;
   for (size_t i = 0; i < length; ++i)
     rtp_packet->data[i + kRtpHeaderSize] = offset + i;
   rtp_packet->length = length + kRtpHeaderSize;
@@ -44,10 +55,9 @@ test::RawRtpPacket* FrameGenerator::NextPacket(int offset, size_t length) {
 }
 
 // Creates a new RtpPacket with the RED header added to the packet.
-test::RawRtpPacket* FrameGenerator::BuildMediaRedPacket(
+RawRtpPacket* FrameGenerator::BuildMediaRedPacket(const RawRtpPacket* packet) {
-    const test::RawRtpPacket* packet) {
   const size_t kHeaderLength = packet->header.header.headerLength;
-  test::RawRtpPacket* red_packet = new test::RawRtpPacket;
+  RawRtpPacket* red_packet = new RawRtpPacket;
   red_packet->header = packet->header;
   red_packet->length = packet->length + 1;  // 1 byte RED header.
   memset(red_packet->data, 0, red_packet->length);
@@ -59,14 +69,14 @@ test::RawRtpPacket* FrameGenerator::BuildMediaRedPacket(
   return red_packet;
 }
 
-// Creates a new RtpPacket with FEC payload and red header. Does this by
+// Creates a new RtpPacket with FEC payload and RED header. Does this by
 // creating a new fake media RtpPacket, clears the marker bit and adds a RED
 // header. Finally replaces the payload with the content of |packet->data|.
-test::RawRtpPacket* FrameGenerator::BuildFecRedPacket(
+RawRtpPacket* FrameGenerator::BuildFecRedPacket(
     const ForwardErrorCorrection::Packet* packet) {
   // Create a fake media packet to get a correct header. 1 byte RED header.
   ++num_packets_;
-  test::RawRtpPacket* red_packet = NextPacket(0, packet->length + 1);
+  RawRtpPacket* red_packet = NextPacket(0, packet->length + 1);
   red_packet->data[1] &= ~0x80;  // Clear marker bit.
   const size_t kHeaderLength = red_packet->header.header.headerLength;
   SetRedHeader(red_packet, kFecPayloadType, kHeaderLength);
@@ -95,4 +105,69 @@ void FrameGenerator::BuildRtpHeader(uint8_t* data, const RTPHeader* header) {
   ByteWriter<uint32_t>::WriteBigEndian(data + 8, header->ssrc);
 }
 
+ForwardErrorCorrection::PacketList MediaPacketGenerator::ConstructMediaPackets(
+    int num_media_packets,
+    uint16_t start_seq_num) {
+  RTC_DCHECK_GT(num_media_packets, 0);
+  uint16_t seq_num = start_seq_num;
+  int time_stamp = random_->Rand<int>();
+
+  ForwardErrorCorrection::PacketList media_packets;
+
+  for (int i = 0; i < num_media_packets; ++i) {
+    std::unique_ptr<ForwardErrorCorrection::Packet> media_packet(
+        new ForwardErrorCorrection::Packet());
+    media_packet->length = random_->Rand(min_packet_size_, max_packet_size_);
+
+    // Generate random values for the first 2 bytes
+    media_packet->data[0] = random_->Rand<uint8_t>();
+    media_packet->data[1] = random_->Rand<uint8_t>();
+
+    // The first two bits are assumed to be 10 by the FEC encoder.
+    // In fact the FEC decoder will set the two first bits to 10 regardless of
+    // what they actually were. Set the first two bits to 10 so that a memcmp
+    // can be performed for the whole restored packet.
+    media_packet->data[0] |= 0x80;
+    media_packet->data[0] &= 0xbf;
+
+    // FEC is applied to a whole frame.
+    // A frame is signaled by multiple packets without the marker bit set
+    // followed by the last packet of the frame for which the marker bit is set.
+    // Only push one (fake) frame to the FEC.
+    media_packet->data[1] &= 0x7f;
+
+    webrtc::ByteWriter<uint16_t>::WriteBigEndian(&media_packet->data[2],
+                                                 seq_num);
+    webrtc::ByteWriter<uint32_t>::WriteBigEndian(&media_packet->data[4],
+                                                 time_stamp);
+    webrtc::ByteWriter<uint32_t>::WriteBigEndian(&media_packet->data[8], ssrc_);
+
+    // Generate random values for payload.
+    for (size_t j = 12; j < media_packet->length; ++j) {
+      media_packet->data[j] = random_->Rand<uint8_t>();
+    }
+    seq_num++;
+    media_packets.push_back(std::move(media_packet));
+  }
+  // Last packet, set marker bit.
+  ForwardErrorCorrection::Packet* media_packet = media_packets.back().get();
+  RTC_DCHECK(media_packet);
+  media_packet->data[1] |= 0x80;
+
+  fec_seq_num_ = seq_num;
+
+  return media_packets;
+}
+
+ForwardErrorCorrection::PacketList MediaPacketGenerator::ConstructMediaPackets(
+    int num_media_packets) {
+  return ConstructMediaPackets(num_media_packets, random_->Rand<uint16_t>());
+}
+
+uint16_t MediaPacketGenerator::GetFecSeqNum() {
+  return fec_seq_num_;
+}
+
+}  // namespace fec
+}  // namespace test
 }  // namespace webrtc

webrtc/modules/rtp_rtcp/source/fec_test_helper.h

@@ -11,19 +11,20 @@
 #ifndef WEBRTC_MODULES_RTP_RTCP_SOURCE_FEC_TEST_HELPER_H_
 #define WEBRTC_MODULES_RTP_RTCP_SOURCE_FEC_TEST_HELPER_H_
 
+#include "webrtc/base/basictypes.h"
+#include "webrtc/base/random.h"
 #include "webrtc/modules/include/module_common_types.h"
 #include "webrtc/modules/rtp_rtcp/source/forward_error_correction.h"
 
 namespace webrtc {
 namespace test {
+
+// Needed to not clash with another webrtc::FrameGenerator.
+namespace fec {
+
 struct RawRtpPacket : public ForwardErrorCorrection::Packet {
   WebRtcRTPHeader header;
 };
-}  // namespace test
-
-const uint8_t kFecPayloadType = 96;
-const uint8_t kRedPayloadType = 97;
-const uint8_t kVp8PayloadType = 120;
 
 class FrameGenerator {
  public:
@@ -33,16 +34,15 @@ class FrameGenerator {
 
   uint16_t NextSeqNum();
 
-  test::RawRtpPacket* NextPacket(int offset, size_t length);
+  RawRtpPacket* NextPacket(int offset, size_t length);
 
   // Creates a new RtpPacket with the RED header added to the packet.
-  test::RawRtpPacket* BuildMediaRedPacket(const test::RawRtpPacket* packet);
+  RawRtpPacket* BuildMediaRedPacket(const RawRtpPacket* packet);
 
   // Creates a new RtpPacket with FEC payload and red header. Does this by
   // creating a new fake media RtpPacket, clears the marker bit and adds a RED
   // header. Finally replaces the payload with the content of |packet->data|.
-  test::RawRtpPacket* BuildFecRedPacket(
+  RawRtpPacket* BuildFecRedPacket(const ForwardErrorCorrection::Packet* packet);
-      const ForwardErrorCorrection::Packet* packet);
 
   void SetRedHeader(ForwardErrorCorrection::Packet* red_packet,
                     uint8_t payload_type,
@@ -55,6 +55,39 @@ class FrameGenerator {
   uint16_t seq_num_;
   uint32_t timestamp_;
 };
+
+class MediaPacketGenerator {
+ public:
+  MediaPacketGenerator(uint32_t min_packet_size,
+                       uint32_t max_packet_size,
+                       uint32_t ssrc,
+                       Random* random)
+      : min_packet_size_(min_packet_size),
+        max_packet_size_(max_packet_size),
+        ssrc_(ssrc),
+        random_(random) {}
+
+  // Construct the media packets, up to |num_media_packets| packets.
+  ForwardErrorCorrection::PacketList ConstructMediaPackets(
+      int num_media_packets,
+      uint16_t start_seq_num);
+  ForwardErrorCorrection::PacketList ConstructMediaPackets(
+      int num_media_packets);
+
+  uint16_t GetFecSeqNum();
+
+ private:
+  uint32_t min_packet_size_;
+  uint32_t max_packet_size_;
+  uint32_t ssrc_;
+  Random* random_;
+
+  ForwardErrorCorrection::PacketList media_packets_;
+  uint16_t fec_seq_num_;
+};
+
+}  // namespace fec
+}  // namespace test
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_RTP_RTCP_SOURCE_FEC_TEST_HELPER_H_

webrtc/modules/rtp_rtcp/source/forward_error_correction.cc

@@ -94,19 +94,18 @@ ForwardErrorCorrection::~ForwardErrorCorrection() {}
 //   |                                                               |
 //   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 //
-// Note that any potential RED headers are added/removed before calling
+int ForwardErrorCorrection::EncodeFec(const PacketList& media_packets,
-// GenerateFec() or DecodeFec().
-int ForwardErrorCorrection::GenerateFec(const PacketList& media_packets,
                                       uint8_t protection_factor,
                                       int num_important_packets,
                                       bool use_unequal_protection,
                                       FecMaskType fec_mask_type,
                                       std::list<Packet*>* fec_packets) {
-  const uint16_t num_media_packets = media_packets.size();
+  const size_t num_media_packets = media_packets.size();
+
   // Sanity check arguments.
-  RTC_DCHECK_GT(num_media_packets, 0);
+  RTC_DCHECK_GT(num_media_packets, 0u);
   RTC_DCHECK_GE(num_important_packets, 0);
-  RTC_DCHECK_LE(num_important_packets, num_media_packets);
+  RTC_DCHECK_LE(static_cast<size_t>(num_important_packets), num_media_packets);
   RTC_DCHECK(fec_packets->empty());
 
   if (num_media_packets > kMaxMediaPackets) {

webrtc/modules/rtp_rtcp/source/forward_error_correction.h

@@ -147,13 +147,15 @@ class ForwardErrorCorrection {
   //                                of type Packet. Must be empty on entry.
   //                                The memory available through the list will
   //                                be valid until the next call to
-  //                                GenerateFec().
+  //                                EncodeFec().
   //
   // Returns 0 on success, -1 on failure.
   //
-  int GenerateFec(const PacketList& media_packets,
+  int EncodeFec(const PacketList& media_packets,
-                  uint8_t protection_factor, int num_important_packets,
+                uint8_t protection_factor,
-                  bool use_unequal_protection, FecMaskType fec_mask_type,
+                int num_important_packets,
+                bool use_unequal_protection,
+                FecMaskType fec_mask_type,
                 std::list<Packet*>* fec_packets);
 
   //

webrtc/modules/rtp_rtcp/source/producer_fec.cc

@@ -24,12 +24,12 @@ namespace webrtc {
 constexpr size_t kRedForFecHeaderLength = 1;
 
 // This controls the maximum amount of excess overhead (actual - target)
-// allowed in order to trigger GenerateFec(), before |params_.max_fec_frames|
+// 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 GenerateFec(), before |params_.max_fec_frames| is
+// level) in order to trigger EncodeFec(), before |params_.max_fec_frames| is
 // reached.
 constexpr size_t kMinMediaPackets = 4;
 
@@ -175,7 +175,7 @@ int ProducerFec::AddRtpPacketAndGenerateFec(const uint8_t* data_buffer,
     // Since unequal protection is disabled, the value of
     // |num_important_packets_| has no importance when calling GenerateFec().
     constexpr bool kUseUnequalProtection = false;
-    int ret = fec_.GenerateFec(media_packets_, params_.fec_rate,
+    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()) {

webrtc/modules/rtp_rtcp/source/producer_fec_unittest.cc

@@ -20,6 +20,14 @@
 
 namespace webrtc {
 
+namespace {
+constexpr uint8_t kFecPayloadType = 96;
+constexpr uint8_t kRedPayloadType = 97;
+}  // namespace
+
+using ::webrtc::test::fec::FrameGenerator;
+using ::webrtc::test::fec::RawRtpPacket;
+
 void VerifyHeader(uint16_t seq_num,
                   uint32_t timestamp,
                   int red_payload_type,
@@ -97,12 +105,12 @@ TEST_F(ProducerFecTest, OneFrameFec) {
   // media packets for 1 frame is at least |minimum_media_packets_fec_|.
   const int kNumPackets = 4;
   FecProtectionParams params = {15, 3, kFecMaskRandom};
-  std::list<test::RawRtpPacket*> rtp_packets;
+  std::list<RawRtpPacket*> rtp_packets;
   generator_.NewFrame(kNumPackets);
   producer_.SetFecParameters(&params, 0);  // Expecting one FEC packet.
   uint32_t last_timestamp = 0;
   for (int i = 0; i < kNumPackets; ++i) {
-    test::RawRtpPacket* rtp_packet = generator_.NextPacket(i, 10);
+    RawRtpPacket* rtp_packet = generator_.NextPacket(i, 10);
     rtp_packets.push_back(rtp_packet);
     EXPECT_EQ(0, producer_.AddRtpPacketAndGenerateFec(
                      rtp_packet->data, rtp_packet->length, kRtpHeaderSize));
@@ -135,14 +143,13 @@ TEST_F(ProducerFecTest, TwoFrameFec) {
   const int kNumFrames = 2;
 
   FecProtectionParams params = {15, 3, kFecMaskRandom};
-  std::list<test::RawRtpPacket*> rtp_packets;
+  std::list<RawRtpPacket*> rtp_packets;
   producer_.SetFecParameters(&params, 0);  // Expecting one FEC packet.
   uint32_t last_timestamp = 0;
   for (int i = 0; i < kNumFrames; ++i) {
     generator_.NewFrame(kNumPackets);
     for (int j = 0; j < kNumPackets; ++j) {
-      test::RawRtpPacket* rtp_packet =
+      RawRtpPacket* rtp_packet = generator_.NextPacket(i * kNumPackets + j, 10);
-          generator_.NextPacket(i * kNumPackets + j, 10);
       rtp_packets.push_back(rtp_packet);
       EXPECT_EQ(0, producer_.AddRtpPacketAndGenerateFec(
                        rtp_packet->data, rtp_packet->length, kRtpHeaderSize));
@@ -166,16 +173,14 @@ TEST_F(ProducerFecTest, TwoFrameFec) {
 
 TEST_F(ProducerFecTest, BuildRedPacket) {
   generator_.NewFrame(1);
-  test::RawRtpPacket* packet = generator_.NextPacket(0, 10);
+  RawRtpPacket* packet = generator_.NextPacket(0, 10);
   std::unique_ptr<RedPacket> red_packet =
       ProducerFec::BuildRedPacket(packet->data, packet->length - kRtpHeaderSize,
                                   kRtpHeaderSize, kRedPayloadType);
   EXPECT_EQ(packet->length + 1, red_packet->length());
   VerifyHeader(packet->header.header.sequenceNumber,
-               packet->header.header.timestamp,
+               packet->header.header.timestamp, kRedPayloadType,
-               kRedPayloadType,
+               packet->header.header.payloadType, red_packet.get(),
-               packet->header.header.payloadType,
-               red_packet.get(),
                true);  // Marker bit set.
   for (int i = 0; i < 10; ++i)
     EXPECT_EQ(i, red_packet->data()[kRtpHeaderSize + 1 + i]);
@@ -188,7 +193,7 @@ TEST_F(ProducerFecTest, BuildRedPacketWithEmptyPayload) {
   constexpr size_t kRedForFecHeaderLength = 1;
 
   generator_.NewFrame(kNumFrames);
-  std::unique_ptr<test::RawRtpPacket> packet(
+  std::unique_ptr<RawRtpPacket> packet(
       generator_.NextPacket(0, kPayloadLength));
   std::unique_ptr<RedPacket> red_packet =
       ProducerFec::BuildRedPacket(packet->data, packet->length - kRtpHeaderSize,

webrtc/modules/rtp_rtcp/test/testFec/test_fec.cc

@@ -277,14 +277,14 @@ TEST(FecTest, MAYBE_FecTest) {
             }
             media_packet_list.back()->data[1] |= 0x80;
 
-            ASSERT_EQ(0, fec.GenerateFec(media_packet_list, protection_factor,
+            ASSERT_EQ(0, fec.EncodeFec(media_packet_list, protection_factor,
                                        num_imp_packets, kUseUnequalProtection,
                                        fec_mask_type, &fec_packet_list))
-                << "GenerateFec() failed";
+                << "EncodeFec() failed";
 
             ASSERT_EQ(num_fec_packets, fec_packet_list.size())
                 << "We requested " << num_fec_packets << " FEC packets, but "
-                << "GenerateFec() produced " << fec_packet_list.size();
+                << "EncodeFec() produced " << fec_packet_list.size();
 
             memset(media_loss_mask, 0, sizeof(media_loss_mask));
             uint32_t media_packet_idx = 0;
@@ -392,8 +392,8 @@ TEST(FecTest, MAYBE_FecTest) {
                   }
                 }
               }
-              ASSERT_EQ(0, fec.DecodeFec(&to_decode_list,
+              ASSERT_EQ(0,
-                                         &recovered_packet_list))
+                        fec.DecodeFec(&to_decode_list, &recovered_packet_list))
                   << "DecodeFec() failed";
               ASSERT_TRUE(to_decode_list.empty())
                   << "Received packet list is not empty.";

webrtc/test/fuzzers/producer_fec_fuzzer.cc

@@ -17,6 +17,11 @@
 
 namespace webrtc {
 
+namespace {
+constexpr uint8_t kFecPayloadType = 96;
+constexpr uint8_t kRedPayloadType = 97;
+}  // namespace
+
 void FuzzOneInput(const uint8_t* data, size_t size) {
   ProducerFec producer;
   size_t i = 0;