Implement the NackModule as part of the new jitter buffer.

webrtc/modules/video_coding/nack_module_unittest.cc

+/*
+ *  Copyright (c) 2016 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 <cstring>
+#include "testing/gtest/include/gtest/gtest.h"
+#include "webrtc/modules/video_coding/include/video_coding_defines.h"
+#include "webrtc/modules/video_coding/nack_module.h"
+#include "webrtc/system_wrappers/include/clock.h"
+#include "webrtc/base/mod_ops.h"
+
+namespace webrtc {
+class TestNackModule : public ::testing::Test,
+                       public NackSender,
+                       public KeyFrameRequestSender {
+ protected:
+  TestNackModule()
+      : clock_(new SimulatedClock(0)),
+        nack_module_(clock_.get(), this, this),
+        keyframes_requested_(0) {}
+
+  void SendNack(const std::vector<uint16_t>& sequence_numbers) override {
+    sent_nacks_.insert(
+      sent_nacks_.end(),
+      sequence_numbers.begin(),
+      sequence_numbers.end());
+  }
+
+  void RequestKeyFrame() override {
+    ++keyframes_requested_;
+  }
+
+  std::unique_ptr<SimulatedClock> clock_;
+  NackModule nack_module_;
+  std::vector<uint16_t> sent_nacks_;
+  int keyframes_requested_;
+};
+
+TEST_F(TestNackModule, NackOnePacket) {
+  VCMPacket packet;
+  packet.seqNum = 1;
+  nack_module_.OnReceivedPacket(packet);
+  packet.seqNum = 3;
+  nack_module_.OnReceivedPacket(packet);
+  EXPECT_EQ(1u, sent_nacks_.size());
+  EXPECT_EQ(2, sent_nacks_[0]);
+}
+
+TEST_F(TestNackModule, WrappingSeqNum) {
+  VCMPacket packet;
+  packet.seqNum = 0xfffe;
+  nack_module_.OnReceivedPacket(packet);
+  packet.seqNum = 1;
+  nack_module_.OnReceivedPacket(packet);
+  EXPECT_EQ(2u, sent_nacks_.size());
+  EXPECT_EQ(0xffff, sent_nacks_[0]);
+  EXPECT_EQ(0, sent_nacks_[1]);
+}
+
+TEST_F(TestNackModule, WrappingSeqNumClearToKeyframe) {
+  VCMPacket packet;
+  packet.seqNum = 0xfffe;
+  nack_module_.OnReceivedPacket(packet);
+  packet.seqNum = 1;
+  nack_module_.OnReceivedPacket(packet);
+  EXPECT_EQ(2u, sent_nacks_.size());
+  EXPECT_EQ(0xffff, sent_nacks_[0]);
+  EXPECT_EQ(0, sent_nacks_[1]);
+
+  sent_nacks_.clear();
+  packet.frameType = kVideoFrameKey;
+  packet.isFirstPacket = true;
+  packet.seqNum = 2;
+  nack_module_.OnReceivedPacket(packet);
+  EXPECT_EQ(0u, sent_nacks_.size());
+
+  packet.seqNum = 501;
+  nack_module_.OnReceivedPacket(packet);
+  EXPECT_EQ(498u, sent_nacks_.size());
+  for (int seq_num = 3; seq_num < 501; ++seq_num)
+    EXPECT_EQ(seq_num, sent_nacks_[seq_num - 3]);
+
+  sent_nacks_.clear();
+  packet.frameType = kVideoFrameDelta;
+  packet.seqNum = 1001;
+  nack_module_.OnReceivedPacket(packet);
+  EXPECT_EQ(499u, sent_nacks_.size());
+  for (int seq_num = 502; seq_num < 1001; ++seq_num)
+    EXPECT_EQ(seq_num, sent_nacks_[seq_num - 502]);
+
+  sent_nacks_.clear();
+  clock_->AdvanceTimeMilliseconds(100);
+  nack_module_.Process();
+  EXPECT_EQ(999u, sent_nacks_.size());
+  EXPECT_EQ(0xffff, sent_nacks_[0]);
+  EXPECT_EQ(0, sent_nacks_[1]);
+  for (int seq_num = 3; seq_num < 501; ++seq_num)
+    EXPECT_EQ(seq_num, sent_nacks_[seq_num - 1]);
+  for (int seq_num = 502; seq_num < 1001; ++seq_num)
+    EXPECT_EQ(seq_num, sent_nacks_[seq_num - 2]);
+
+  // Adding packet 1004 will cause the nack list to reach it's max limit.
+  // It will then clear all nacks up to the next keyframe (seq num 2),
+  // thus removing 0xffff and 0 from the nack list.
+  sent_nacks_.clear();
+  packet.seqNum = 1004;
+  nack_module_.OnReceivedPacket(packet);
+  EXPECT_EQ(2u, sent_nacks_.size());
+  EXPECT_EQ(1002, sent_nacks_[0]);
+  EXPECT_EQ(1003, sent_nacks_[1]);
+
+  sent_nacks_.clear();
+  clock_->AdvanceTimeMilliseconds(100);
+  nack_module_.Process();
+  EXPECT_EQ(999u, sent_nacks_.size());
+  for (int seq_num = 3; seq_num < 501; ++seq_num)
+    EXPECT_EQ(seq_num, sent_nacks_[seq_num - 3]);
+  for (int seq_num = 502; seq_num < 1001; ++seq_num)
+    EXPECT_EQ(seq_num, sent_nacks_[seq_num - 4]);
+
+  // Adding packet 1007 will cause the nack module to overflow again, thus
+  // clearing everything up to 501 which is the next keyframe.
+  packet.seqNum = 1007;
+  nack_module_.OnReceivedPacket(packet);
+  sent_nacks_.clear();
+  clock_->AdvanceTimeMilliseconds(100);
+  nack_module_.Process();
+  EXPECT_EQ(503u, sent_nacks_.size());
+  for (int seq_num = 502; seq_num < 1001; ++seq_num)
+    EXPECT_EQ(seq_num, sent_nacks_[seq_num - 502]);
+  EXPECT_EQ(1005, sent_nacks_[501]);
+  EXPECT_EQ(1006, sent_nacks_[502]);
+}
+
+TEST_F(TestNackModule, DontBurstOnTimeSkip) {
+  nack_module_.Process();
+  clock_->AdvanceTimeMilliseconds(20);
+  EXPECT_EQ(0, nack_module_.TimeUntilNextProcess());
+  nack_module_.Process();
+
+  clock_->AdvanceTimeMilliseconds(100);
+  EXPECT_EQ(0, nack_module_.TimeUntilNextProcess());
+  nack_module_.Process();
+  EXPECT_EQ(20, nack_module_.TimeUntilNextProcess());
+
+  clock_->AdvanceTimeMilliseconds(19);
+  EXPECT_EQ(1, nack_module_.TimeUntilNextProcess());
+  clock_->AdvanceTimeMilliseconds(2);
+  nack_module_.Process();
+  EXPECT_EQ(19, nack_module_.TimeUntilNextProcess());
+
+  clock_->AdvanceTimeMilliseconds(19);
+  EXPECT_EQ(0, nack_module_.TimeUntilNextProcess());
+  nack_module_.Process();
+
+  clock_->AdvanceTimeMilliseconds(21);
+  EXPECT_EQ(0, nack_module_.TimeUntilNextProcess());
+  nack_module_.Process();
+  EXPECT_EQ(19, nack_module_.TimeUntilNextProcess());
+}
+
+TEST_F(TestNackModule, ResendNack) {
+  VCMPacket packet;
+  packet.seqNum = 1;
+  nack_module_.OnReceivedPacket(packet);
+  packet.seqNum = 3;
+  nack_module_.OnReceivedPacket(packet);
+  EXPECT_EQ(1u, sent_nacks_.size());
+  EXPECT_EQ(2, sent_nacks_[0]);
+
+  // Default RTT is 100
+  clock_->AdvanceTimeMilliseconds(99);
+  nack_module_.Process();
+  EXPECT_EQ(1u, sent_nacks_.size());
+
+  clock_->AdvanceTimeMilliseconds(1);
+  nack_module_.Process();
+  EXPECT_EQ(2u, sent_nacks_.size());
+
+  nack_module_.UpdateRtt(50);
+  clock_->AdvanceTimeMilliseconds(100);
+  nack_module_.Process();
+  EXPECT_EQ(3u, sent_nacks_.size());
+
+  clock_->AdvanceTimeMilliseconds(50);
+  nack_module_.Process();
+  EXPECT_EQ(4u, sent_nacks_.size());
+
+  packet.seqNum = 2;
+  nack_module_.OnReceivedPacket(packet);
+  clock_->AdvanceTimeMilliseconds(50);
+  nack_module_.Process();
+  EXPECT_EQ(4u, sent_nacks_.size());
+}
+
+TEST_F(TestNackModule, ResendPacketMaxRetries) {
+  VCMPacket packet;
+  packet.seqNum = 1;
+  nack_module_.OnReceivedPacket(packet);
+  packet.seqNum = 3;
+  nack_module_.OnReceivedPacket(packet);
+  EXPECT_EQ(1u, sent_nacks_.size());
+  EXPECT_EQ(2, sent_nacks_[0]);
+
+  for (size_t retries = 1; retries < 10; ++retries) {
+    clock_->AdvanceTimeMilliseconds(100);
+    nack_module_.Process();
+    EXPECT_EQ(retries + 1, sent_nacks_.size());
+  }
+
+  clock_->AdvanceTimeMilliseconds(100);
+  nack_module_.Process();
+  EXPECT_EQ(10u, sent_nacks_.size());
+}
+
+TEST_F(TestNackModule, TooLargeNackList) {
+  VCMPacket packet;
+  packet.seqNum = 0;
+  nack_module_.OnReceivedPacket(packet);
+  packet.seqNum = 1001;
+  nack_module_.OnReceivedPacket(packet);
+  EXPECT_EQ(1000u, sent_nacks_.size());
+  EXPECT_EQ(0, keyframes_requested_);
+  packet.seqNum = 1003;
+  nack_module_.OnReceivedPacket(packet);
+  EXPECT_EQ(1000u, sent_nacks_.size());
+  EXPECT_EQ(1, keyframes_requested_);
+  packet.seqNum = 1004;
+  nack_module_.OnReceivedPacket(packet);
+  EXPECT_EQ(1000u, sent_nacks_.size());
+  EXPECT_EQ(1, keyframes_requested_);
+}
+
+TEST_F(TestNackModule, TooLargeNackListWithKeyFrame) {
+  VCMPacket packet;
+  packet.seqNum = 0;
+  nack_module_.OnReceivedPacket(packet);
+  packet.seqNum = 1;
+  packet.isFirstPacket = true;
+  packet.frameType = kVideoFrameKey;
+  nack_module_.OnReceivedPacket(packet);
+  packet.seqNum = 1001;
+  packet.isFirstPacket = false;
+  packet.frameType = kVideoFrameKey;
+  nack_module_.OnReceivedPacket(packet);
+  EXPECT_EQ(999u, sent_nacks_.size());
+  EXPECT_EQ(0, keyframes_requested_);
+  packet.seqNum = 1003;
+  nack_module_.OnReceivedPacket(packet);
+  EXPECT_EQ(1000u, sent_nacks_.size());
+  EXPECT_EQ(0, keyframes_requested_);
+  packet.seqNum = 1005;
+  nack_module_.OnReceivedPacket(packet);
+  EXPECT_EQ(1000u, sent_nacks_.size());
+  EXPECT_EQ(1, keyframes_requested_);
+}
+
+TEST_F(TestNackModule, ClearUpTo) {
+  VCMPacket packet;
+  packet.seqNum = 0;
+  nack_module_.OnReceivedPacket(packet);
+  packet.seqNum = 100;
+  nack_module_.OnReceivedPacket(packet);
+  EXPECT_EQ(99u, sent_nacks_.size());
+
+  sent_nacks_.clear();
+  clock_->AdvanceTimeMilliseconds(100);
+  nack_module_.ClearUpTo(50);
+  nack_module_.Process();
+  EXPECT_EQ(50u, sent_nacks_.size());
+  EXPECT_EQ(50, sent_nacks_[0]);
+}
+
+TEST_F(TestNackModule, ClearUpToWrap) {
+  VCMPacket packet;
+  packet.seqNum = 0xfff0;
+  nack_module_.OnReceivedPacket(packet);
+  packet.seqNum = 0xf;
+  nack_module_.OnReceivedPacket(packet);
+  EXPECT_EQ(30u, sent_nacks_.size());
+
+  sent_nacks_.clear();
+  clock_->AdvanceTimeMilliseconds(100);
+  nack_module_.ClearUpTo(0);
+  nack_module_.Process();
+  EXPECT_EQ(15u, sent_nacks_.size());
+  EXPECT_EQ(0, sent_nacks_[0]);
+}
+
+}  // namespace webrtc