NackModule2: Rename to NackRequester.
The alternative new name proposed, NackTracker, is already in
use in audio_coding.
Fixed: webrtc:11594
Change-Id: I6a05fafc05fa7ddb18ea4f64886a135e5ef59f7e
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/226744
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Markus Handell <handellm@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34539}
diff --git a/modules/video_coding/nack_requester_unittest.cc b/modules/video_coding/nack_requester_unittest.cc
new file mode 100644
index 0000000..c9659e3
--- /dev/null
+++ b/modules/video_coding/nack_requester_unittest.cc
@@ -0,0 +1,420 @@
+/*
+ * 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 "modules/video_coding/nack_requester.h"
+
+#include <algorithm>
+#include <cstdint>
+#include <cstring>
+#include <memory>
+
+#include "system_wrappers/include/clock.h"
+#include "test/field_trial.h"
+#include "test/gtest.h"
+#include "test/run_loop.h"
+
+namespace webrtc {
+// TODO(bugs.webrtc.org/11594): Use the use the GlobalSimulatedTimeController
+// instead of RunLoop. At the moment we mix use of the Clock and the underlying
+// implementation of RunLoop, which is realtime.
+class TestNackRequester : public ::testing::TestWithParam<bool>,
+ public NackSender,
+ public KeyFrameRequestSender {
+ protected:
+ TestNackRequester()
+ : clock_(new SimulatedClock(0)),
+ field_trial_(GetParam()
+ ? "WebRTC-ExponentialNackBackoff/enabled:true/"
+ : "WebRTC-ExponentialNackBackoff/enabled:false/"),
+ keyframes_requested_(0) {}
+
+ void SetUp() override {}
+
+ void SendNack(const std::vector<uint16_t>& sequence_numbers,
+ bool buffering_allowed) override {
+ sent_nacks_.insert(sent_nacks_.end(), sequence_numbers.begin(),
+ sequence_numbers.end());
+ if (waiting_for_send_nack_) {
+ waiting_for_send_nack_ = false;
+ loop_.Quit();
+ }
+ }
+
+ void RequestKeyFrame() override { ++keyframes_requested_; }
+
+ void Flush() {
+ // nack_module.Process();
+ loop_.Flush();
+ }
+
+ bool WaitForSendNack() {
+ if (timed_out_) {
+ RTC_NOTREACHED();
+ return false;
+ }
+
+ RTC_DCHECK(!waiting_for_send_nack_);
+
+ waiting_for_send_nack_ = true;
+ loop_.PostDelayedTask(
+ [this]() {
+ timed_out_ = true;
+ loop_.Quit();
+ },
+ 1000);
+
+ loop_.Run();
+
+ if (timed_out_)
+ return false;
+
+ RTC_DCHECK(!waiting_for_send_nack_);
+ return true;
+ }
+
+ NackRequester& CreateNackModule(
+ TimeDelta interval = NackPeriodicProcessor::kUpdateInterval) {
+ RTC_DCHECK(!nack_module_.get());
+ nack_periodic_processor_ =
+ std::make_unique<NackPeriodicProcessor>(interval);
+ nack_module_ = std::make_unique<NackRequester>(
+ TaskQueueBase::Current(), nack_periodic_processor_.get(), clock_.get(),
+ this, this);
+ nack_module_->UpdateRtt(kDefaultRttMs);
+ return *nack_module_.get();
+ }
+
+ static constexpr int64_t kDefaultRttMs = 20;
+ test::RunLoop loop_;
+ std::unique_ptr<SimulatedClock> clock_;
+ test::ScopedFieldTrials field_trial_;
+ std::unique_ptr<NackPeriodicProcessor> nack_periodic_processor_;
+ std::unique_ptr<NackRequester> nack_module_;
+ std::vector<uint16_t> sent_nacks_;
+ int keyframes_requested_;
+ bool waiting_for_send_nack_ = false;
+ bool timed_out_ = false;
+};
+
+TEST_P(TestNackRequester, NackOnePacket) {
+ NackRequester& nack_module = CreateNackModule();
+ nack_module.OnReceivedPacket(1, false, false);
+ nack_module.OnReceivedPacket(3, false, false);
+ ASSERT_EQ(1u, sent_nacks_.size());
+ EXPECT_EQ(2, sent_nacks_[0]);
+}
+
+TEST_P(TestNackRequester, WrappingSeqNum) {
+ NackRequester& nack_module = CreateNackModule();
+ nack_module.OnReceivedPacket(0xfffe, false, false);
+ nack_module.OnReceivedPacket(1, false, false);
+ ASSERT_EQ(2u, sent_nacks_.size());
+ EXPECT_EQ(0xffff, sent_nacks_[0]);
+ EXPECT_EQ(0, sent_nacks_[1]);
+}
+
+TEST_P(TestNackRequester, WrappingSeqNumClearToKeyframe) {
+ NackRequester& nack_module = CreateNackModule(TimeDelta::Millis(10));
+ nack_module.OnReceivedPacket(0xfffe, false, false);
+ nack_module.OnReceivedPacket(1, false, false);
+ ASSERT_EQ(2u, sent_nacks_.size());
+ EXPECT_EQ(0xffff, sent_nacks_[0]);
+ EXPECT_EQ(0, sent_nacks_[1]);
+
+ sent_nacks_.clear();
+ nack_module.OnReceivedPacket(2, true, false);
+ ASSERT_EQ(0u, sent_nacks_.size());
+
+ nack_module.OnReceivedPacket(501, true, false);
+ ASSERT_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();
+ nack_module.OnReceivedPacket(1001, false, false);
+ 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);
+ ASSERT_TRUE(WaitForSendNack());
+ ASSERT_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();
+ nack_module.OnReceivedPacket(1004, false, false);
+ ASSERT_EQ(2u, sent_nacks_.size());
+ EXPECT_EQ(1002, sent_nacks_[0]);
+ EXPECT_EQ(1003, sent_nacks_[1]);
+
+ sent_nacks_.clear();
+ clock_->AdvanceTimeMilliseconds(100);
+ ASSERT_TRUE(WaitForSendNack());
+ ASSERT_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.
+ nack_module.OnReceivedPacket(1007, false, false);
+ sent_nacks_.clear();
+ clock_->AdvanceTimeMilliseconds(100);
+ ASSERT_TRUE(WaitForSendNack());
+ ASSERT_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_P(TestNackRequester, ResendNack) {
+ NackRequester& nack_module = CreateNackModule(TimeDelta::Millis(1));
+ nack_module.OnReceivedPacket(1, false, false);
+ nack_module.OnReceivedPacket(3, false, false);
+ size_t expected_nacks_sent = 1;
+ ASSERT_EQ(expected_nacks_sent, sent_nacks_.size());
+ EXPECT_EQ(2, sent_nacks_[0]);
+
+ if (GetParam()) {
+ // Retry has to wait at least 5ms by default.
+ nack_module.UpdateRtt(1);
+ clock_->AdvanceTimeMilliseconds(4);
+ Flush(); // Too early.
+ EXPECT_EQ(expected_nacks_sent, sent_nacks_.size());
+
+ clock_->AdvanceTimeMilliseconds(1);
+ WaitForSendNack(); // Now allowed.
+ EXPECT_EQ(++expected_nacks_sent, sent_nacks_.size());
+ } else {
+ nack_module.UpdateRtt(1);
+ clock_->AdvanceTimeMilliseconds(1);
+ WaitForSendNack(); // Fast retransmit allowed.
+ EXPECT_EQ(++expected_nacks_sent, sent_nacks_.size());
+ }
+
+ // N:th try has to wait b^(N-1) * rtt by default.
+ const double b = GetParam() ? 1.25 : 1.0;
+ for (int i = 2; i < 10; ++i) {
+ // Change RTT, above the 40ms max for exponential backoff.
+ TimeDelta rtt = TimeDelta::Millis(160); // + (i * 10 - 40)
+ nack_module.UpdateRtt(rtt.ms());
+
+ // RTT gets capped at 160ms in backoff calculations.
+ TimeDelta expected_backoff_delay =
+ std::pow(b, i - 1) * std::min(rtt, TimeDelta::Millis(160));
+
+ // Move to one millisecond before next allowed NACK.
+ clock_->AdvanceTimeMilliseconds(expected_backoff_delay.ms() - 1);
+ Flush();
+ EXPECT_EQ(expected_nacks_sent, sent_nacks_.size());
+
+ // Move to one millisecond after next allowed NACK.
+ // After rather than on to avoid rounding errors.
+ clock_->AdvanceTimeMilliseconds(2);
+ WaitForSendNack(); // Now allowed.
+ EXPECT_EQ(++expected_nacks_sent, sent_nacks_.size());
+ }
+
+ // Giving up after 10 tries.
+ clock_->AdvanceTimeMilliseconds(3000);
+ Flush();
+ EXPECT_EQ(expected_nacks_sent, sent_nacks_.size());
+}
+
+TEST_P(TestNackRequester, ResendPacketMaxRetries) {
+ NackRequester& nack_module = CreateNackModule(TimeDelta::Millis(1));
+ nack_module.OnReceivedPacket(1, false, false);
+ nack_module.OnReceivedPacket(3, false, false);
+ ASSERT_EQ(1u, sent_nacks_.size());
+ EXPECT_EQ(2, sent_nacks_[0]);
+
+ int backoff_factor = 1;
+ for (size_t retries = 1; retries < 10; ++retries) {
+ // Exponential backoff, so that we don't reject NACK because of time.
+ clock_->AdvanceTimeMilliseconds(backoff_factor * kDefaultRttMs);
+ backoff_factor *= 2;
+ WaitForSendNack();
+ EXPECT_EQ(retries + 1, sent_nacks_.size());
+ }
+
+ clock_->AdvanceTimeMilliseconds(backoff_factor * kDefaultRttMs);
+ Flush();
+ EXPECT_EQ(10u, sent_nacks_.size());
+}
+
+TEST_P(TestNackRequester, TooLargeNackList) {
+ NackRequester& nack_module = CreateNackModule();
+ nack_module.OnReceivedPacket(0, false, false);
+ nack_module.OnReceivedPacket(1001, false, false);
+ EXPECT_EQ(1000u, sent_nacks_.size());
+ EXPECT_EQ(0, keyframes_requested_);
+ nack_module.OnReceivedPacket(1003, false, false);
+ EXPECT_EQ(1000u, sent_nacks_.size());
+ EXPECT_EQ(1, keyframes_requested_);
+ nack_module.OnReceivedPacket(1004, false, false);
+ EXPECT_EQ(1000u, sent_nacks_.size());
+ EXPECT_EQ(1, keyframes_requested_);
+}
+
+TEST_P(TestNackRequester, TooLargeNackListWithKeyFrame) {
+ NackRequester& nack_module = CreateNackModule();
+ nack_module.OnReceivedPacket(0, false, false);
+ nack_module.OnReceivedPacket(1, true, false);
+ nack_module.OnReceivedPacket(1001, false, false);
+ EXPECT_EQ(999u, sent_nacks_.size());
+ EXPECT_EQ(0, keyframes_requested_);
+ nack_module.OnReceivedPacket(1003, false, false);
+ EXPECT_EQ(1000u, sent_nacks_.size());
+ EXPECT_EQ(0, keyframes_requested_);
+ nack_module.OnReceivedPacket(1005, false, false);
+ EXPECT_EQ(1000u, sent_nacks_.size());
+ EXPECT_EQ(1, keyframes_requested_);
+}
+
+TEST_P(TestNackRequester, ClearUpTo) {
+ NackRequester& nack_module = CreateNackModule(TimeDelta::Millis(1));
+ nack_module.OnReceivedPacket(0, false, false);
+ nack_module.OnReceivedPacket(100, false, false);
+ EXPECT_EQ(99u, sent_nacks_.size());
+
+ sent_nacks_.clear();
+ clock_->AdvanceTimeMilliseconds(100);
+ nack_module.ClearUpTo(50);
+ WaitForSendNack();
+ ASSERT_EQ(50u, sent_nacks_.size());
+ EXPECT_EQ(50, sent_nacks_[0]);
+}
+
+TEST_P(TestNackRequester, ClearUpToWrap) {
+ NackRequester& nack_module = CreateNackModule();
+ nack_module.OnReceivedPacket(0xfff0, false, false);
+ nack_module.OnReceivedPacket(0xf, false, false);
+ EXPECT_EQ(30u, sent_nacks_.size());
+
+ sent_nacks_.clear();
+ clock_->AdvanceTimeMilliseconds(100);
+ nack_module.ClearUpTo(0);
+ WaitForSendNack();
+ ASSERT_EQ(15u, sent_nacks_.size());
+ EXPECT_EQ(0, sent_nacks_[0]);
+}
+
+TEST_P(TestNackRequester, PacketNackCount) {
+ NackRequester& nack_module = CreateNackModule(TimeDelta::Millis(1));
+ EXPECT_EQ(0, nack_module.OnReceivedPacket(0, false, false));
+ EXPECT_EQ(0, nack_module.OnReceivedPacket(2, false, false));
+ EXPECT_EQ(1, nack_module.OnReceivedPacket(1, false, false));
+
+ sent_nacks_.clear();
+ nack_module.UpdateRtt(100);
+ EXPECT_EQ(0, nack_module.OnReceivedPacket(5, false, false));
+ clock_->AdvanceTimeMilliseconds(100);
+ WaitForSendNack();
+ EXPECT_EQ(4u, sent_nacks_.size());
+
+ clock_->AdvanceTimeMilliseconds(125);
+ WaitForSendNack();
+
+ EXPECT_EQ(6u, sent_nacks_.size());
+
+ EXPECT_EQ(3, nack_module.OnReceivedPacket(3, false, false));
+ EXPECT_EQ(3, nack_module.OnReceivedPacket(4, false, false));
+ EXPECT_EQ(0, nack_module.OnReceivedPacket(4, false, false));
+}
+
+TEST_P(TestNackRequester, NackListFullAndNoOverlapWithKeyframes) {
+ NackRequester& nack_module = CreateNackModule();
+ const int kMaxNackPackets = 1000;
+ const unsigned int kFirstGap = kMaxNackPackets - 20;
+ const unsigned int kSecondGap = 200;
+ uint16_t seq_num = 0;
+ nack_module.OnReceivedPacket(seq_num++, true, false);
+ seq_num += kFirstGap;
+ nack_module.OnReceivedPacket(seq_num++, true, false);
+ EXPECT_EQ(kFirstGap, sent_nacks_.size());
+ sent_nacks_.clear();
+ seq_num += kSecondGap;
+ nack_module.OnReceivedPacket(seq_num, true, false);
+ EXPECT_EQ(kSecondGap, sent_nacks_.size());
+}
+
+TEST_P(TestNackRequester, HandleFecRecoveredPacket) {
+ NackRequester& nack_module = CreateNackModule();
+ nack_module.OnReceivedPacket(1, false, false);
+ nack_module.OnReceivedPacket(4, false, true);
+ EXPECT_EQ(0u, sent_nacks_.size());
+ nack_module.OnReceivedPacket(5, false, false);
+ EXPECT_EQ(2u, sent_nacks_.size());
+}
+
+TEST_P(TestNackRequester, SendNackWithoutDelay) {
+ NackRequester& nack_module = CreateNackModule();
+ nack_module.OnReceivedPacket(0, false, false);
+ nack_module.OnReceivedPacket(100, false, false);
+ EXPECT_EQ(99u, sent_nacks_.size());
+}
+
+INSTANTIATE_TEST_SUITE_P(WithAndWithoutBackoff,
+ TestNackRequester,
+ ::testing::Values(true, false));
+
+class TestNackRequesterWithFieldTrial : public ::testing::Test,
+ public NackSender,
+ public KeyFrameRequestSender {
+ protected:
+ TestNackRequesterWithFieldTrial()
+ : nack_delay_field_trial_("WebRTC-SendNackDelayMs/10/"),
+ clock_(new SimulatedClock(0)),
+ nack_module_(TaskQueueBase::Current(),
+ &nack_periodic_processor_,
+ clock_.get(),
+ this,
+ this),
+ keyframes_requested_(0) {}
+
+ void SendNack(const std::vector<uint16_t>& sequence_numbers,
+ bool buffering_allowed) override {
+ sent_nacks_.insert(sent_nacks_.end(), sequence_numbers.begin(),
+ sequence_numbers.end());
+ }
+
+ void RequestKeyFrame() override { ++keyframes_requested_; }
+
+ test::ScopedFieldTrials nack_delay_field_trial_;
+ std::unique_ptr<SimulatedClock> clock_;
+ NackPeriodicProcessor nack_periodic_processor_;
+ NackRequester nack_module_;
+ std::vector<uint16_t> sent_nacks_;
+ int keyframes_requested_;
+};
+
+TEST_F(TestNackRequesterWithFieldTrial, SendNackWithDelay) {
+ nack_module_.OnReceivedPacket(0, false, false);
+ nack_module_.OnReceivedPacket(100, false, false);
+ EXPECT_EQ(0u, sent_nacks_.size());
+ clock_->AdvanceTimeMilliseconds(10);
+ nack_module_.OnReceivedPacket(106, false, false);
+ EXPECT_EQ(99u, sent_nacks_.size());
+ clock_->AdvanceTimeMilliseconds(10);
+ nack_module_.OnReceivedPacket(109, false, false);
+ EXPECT_EQ(104u, sent_nacks_.size());
+}
+} // namespace webrtc