xref: /aosp_15_r20/external/webrtc/video/end_to_end_tests/rtp_rtcp_tests.cc (revision d9f758449e529ab9291ac668be2861e7a55c2422)
1 /*
2  *  Copyright 2018 The WebRTC project authors. All Rights Reserved.
3  *
4  *  Use of this source code is governed by a BSD-style license
5  *  that can be found in the LICENSE file in the root of the source
6  *  tree. An additional intellectual property rights grant can be found
7  *  in the file PATENTS.  All contributing project authors may
8  *  be found in the AUTHORS file in the root of the source tree.
9  */
10 
11 #include <memory>
12 
13 #include "api/test/simulated_network.h"
14 #include "call/fake_network_pipe.h"
15 #include "call/simulated_network.h"
16 #include "modules/include/module_common_types_public.h"
17 #include "modules/rtp_rtcp/source/rtp_packet.h"
18 #include "modules/video_coding/codecs/vp8/include/vp8.h"
19 #include "rtc_base/synchronization/mutex.h"
20 #include "rtc_base/task_queue_for_test.h"
21 #include "test/call_test.h"
22 #include "test/gtest.h"
23 #include "test/rtcp_packet_parser.h"
24 
25 namespace webrtc {
26 namespace {
27 enum : int {  // The first valid value is 1.
28   kTransportSequenceNumberExtensionId = 1,
29 };
30 }  // namespace
31 
32 class RtpRtcpEndToEndTest : public test::CallTest {
33  protected:
34   void RespectsRtcpMode(RtcpMode rtcp_mode);
35   void TestRtpStatePreservation(bool use_rtx, bool provoke_rtcpsr_before_rtp);
36 };
37 
RespectsRtcpMode(RtcpMode rtcp_mode)38 void RtpRtcpEndToEndTest::RespectsRtcpMode(RtcpMode rtcp_mode) {
39   static const int kNumCompoundRtcpPacketsToObserve = 10;
40   class RtcpModeObserver : public test::EndToEndTest {
41    public:
42     explicit RtcpModeObserver(RtcpMode rtcp_mode)
43         : EndToEndTest(kDefaultTimeout),
44           rtcp_mode_(rtcp_mode),
45           sent_rtp_(0),
46           sent_rtcp_(0) {}
47 
48    private:
49     Action OnSendRtp(const uint8_t* packet, size_t length) override {
50       MutexLock lock(&mutex_);
51       if (++sent_rtp_ % 3 == 0)
52         return DROP_PACKET;
53 
54       return SEND_PACKET;
55     }
56 
57     Action OnReceiveRtcp(const uint8_t* packet, size_t length) override {
58       MutexLock lock(&mutex_);
59       ++sent_rtcp_;
60       test::RtcpPacketParser parser;
61       EXPECT_TRUE(parser.Parse(packet, length));
62 
63       EXPECT_EQ(0, parser.sender_report()->num_packets());
64 
65       switch (rtcp_mode_) {
66         case RtcpMode::kCompound:
67           // TODO(holmer): We shouldn't send transport feedback alone if
68           // compound RTCP is negotiated.
69           if (parser.receiver_report()->num_packets() == 0 &&
70               parser.transport_feedback()->num_packets() == 0) {
71             ADD_FAILURE() << "Received RTCP packet without receiver report for "
72                              "RtcpMode::kCompound.";
73             observation_complete_.Set();
74           }
75 
76           if (sent_rtcp_ >= kNumCompoundRtcpPacketsToObserve)
77             observation_complete_.Set();
78 
79           break;
80         case RtcpMode::kReducedSize:
81           if (parser.receiver_report()->num_packets() == 0)
82             observation_complete_.Set();
83           break;
84         case RtcpMode::kOff:
85           RTC_DCHECK_NOTREACHED();
86           break;
87       }
88 
89       return SEND_PACKET;
90     }
91 
92     void ModifyVideoConfigs(
93         VideoSendStream::Config* send_config,
94         std::vector<VideoReceiveStreamInterface::Config>* receive_configs,
95         VideoEncoderConfig* encoder_config) override {
96       send_config->rtp.nack.rtp_history_ms = kNackRtpHistoryMs;
97       (*receive_configs)[0].rtp.nack.rtp_history_ms = kNackRtpHistoryMs;
98       (*receive_configs)[0].rtp.rtcp_mode = rtcp_mode_;
99     }
100 
101     void PerformTest() override {
102       EXPECT_TRUE(Wait())
103           << (rtcp_mode_ == RtcpMode::kCompound
104                   ? "Timed out before observing enough compound packets."
105                   : "Timed out before receiving a non-compound RTCP packet.");
106     }
107 
108     RtcpMode rtcp_mode_;
109     Mutex mutex_;
110     // Must be protected since RTCP can be sent by both the process thread
111     // and the pacer thread.
112     int sent_rtp_ RTC_GUARDED_BY(&mutex_);
113     int sent_rtcp_ RTC_GUARDED_BY(&mutex_);
114   } test(rtcp_mode);
115 
116   RunBaseTest(&test);
117 }
118 
TEST_F(RtpRtcpEndToEndTest,UsesRtcpCompoundMode)119 TEST_F(RtpRtcpEndToEndTest, UsesRtcpCompoundMode) {
120   RespectsRtcpMode(RtcpMode::kCompound);
121 }
122 
TEST_F(RtpRtcpEndToEndTest,UsesRtcpReducedSizeMode)123 TEST_F(RtpRtcpEndToEndTest, UsesRtcpReducedSizeMode) {
124   RespectsRtcpMode(RtcpMode::kReducedSize);
125 }
126 
TestRtpStatePreservation(bool use_rtx,bool provoke_rtcpsr_before_rtp)127 void RtpRtcpEndToEndTest::TestRtpStatePreservation(
128     bool use_rtx,
129     bool provoke_rtcpsr_before_rtp) {
130   // This test uses other VideoStream settings than the the default settings
131   // implemented in DefaultVideoStreamFactory. Therefore this test implements
132   // its own VideoEncoderConfig::VideoStreamFactoryInterface which is created
133   // in ModifyVideoConfigs.
134   class VideoStreamFactory
135       : public VideoEncoderConfig::VideoStreamFactoryInterface {
136    public:
137     VideoStreamFactory() {}
138 
139    private:
140     std::vector<VideoStream> CreateEncoderStreams(
141         int frame_width,
142         int frame_height,
143         const VideoEncoderConfig& encoder_config) override {
144       std::vector<VideoStream> streams =
145           test::CreateVideoStreams(frame_width, frame_height, encoder_config);
146 
147       if (encoder_config.number_of_streams > 1) {
148         // Lower bitrates so that all streams send initially.
149         RTC_DCHECK_EQ(3, encoder_config.number_of_streams);
150         for (size_t i = 0; i < encoder_config.number_of_streams; ++i) {
151           streams[i].min_bitrate_bps = 10000;
152           streams[i].target_bitrate_bps = 15000;
153           streams[i].max_bitrate_bps = 20000;
154         }
155       } else {
156         // Use the same total bitrates when sending a single stream to avoid
157         // lowering
158         // the bitrate estimate and requiring a subsequent rampup.
159         streams[0].min_bitrate_bps = 3 * 10000;
160         streams[0].target_bitrate_bps = 3 * 15000;
161         streams[0].max_bitrate_bps = 3 * 20000;
162       }
163       return streams;
164     }
165   };
166 
167   class RtpSequenceObserver : public test::RtpRtcpObserver {
168    public:
169     explicit RtpSequenceObserver(bool use_rtx)
170         : test::RtpRtcpObserver(kDefaultTimeout),
171           ssrcs_to_observe_(kNumSimulcastStreams) {
172       for (size_t i = 0; i < kNumSimulcastStreams; ++i) {
173         ssrc_is_rtx_[kVideoSendSsrcs[i]] = false;
174         if (use_rtx)
175           ssrc_is_rtx_[kSendRtxSsrcs[i]] = true;
176       }
177     }
178 
179     void ResetExpectedSsrcs(size_t num_expected_ssrcs) {
180       MutexLock lock(&mutex_);
181       ssrc_observed_.clear();
182       ssrcs_to_observe_ = num_expected_ssrcs;
183     }
184 
185    private:
186     void ValidateTimestampGap(uint32_t ssrc,
187                               uint32_t timestamp,
188                               bool only_padding)
189         RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_) {
190       static const int32_t kMaxTimestampGap = kDefaultTimeout.ms() * 90;
191       auto timestamp_it = last_observed_timestamp_.find(ssrc);
192       if (timestamp_it == last_observed_timestamp_.end()) {
193         EXPECT_FALSE(only_padding);
194         last_observed_timestamp_[ssrc] = timestamp;
195       } else {
196         // Verify timestamps are reasonably close.
197         uint32_t latest_observed = timestamp_it->second;
198         // Wraparound handling is unnecessary here as long as an int variable
199         // is used to store the result.
200         int32_t timestamp_gap = timestamp - latest_observed;
201         EXPECT_LE(std::abs(timestamp_gap), kMaxTimestampGap)
202             << "Gap in timestamps (" << latest_observed << " -> " << timestamp
203             << ") too large for SSRC: " << ssrc << ".";
204         timestamp_it->second = timestamp;
205       }
206     }
207 
208     Action OnSendRtp(const uint8_t* packet, size_t length) override {
209       RtpPacket rtp_packet;
210       EXPECT_TRUE(rtp_packet.Parse(packet, length));
211       const uint32_t ssrc = rtp_packet.Ssrc();
212       const int64_t sequence_number =
213           seq_numbers_unwrapper_.Unwrap(rtp_packet.SequenceNumber());
214       const uint32_t timestamp = rtp_packet.Timestamp();
215       const bool only_padding = rtp_packet.payload_size() == 0;
216 
217       EXPECT_TRUE(ssrc_is_rtx_.find(ssrc) != ssrc_is_rtx_.end())
218           << "Received SSRC that wasn't configured: " << ssrc;
219 
220       static const int64_t kMaxSequenceNumberGap = 100;
221       std::list<int64_t>* seq_numbers = &last_observed_seq_numbers_[ssrc];
222       if (seq_numbers->empty()) {
223         seq_numbers->push_back(sequence_number);
224       } else {
225         // We shouldn't get replays of previous sequence numbers.
226         for (int64_t observed : *seq_numbers) {
227           EXPECT_NE(observed, sequence_number)
228               << "Received sequence number " << sequence_number << " for SSRC "
229               << ssrc << " 2nd time.";
230         }
231         // Verify sequence numbers are reasonably close.
232         int64_t latest_observed = seq_numbers->back();
233         int64_t sequence_number_gap = sequence_number - latest_observed;
234         EXPECT_LE(std::abs(sequence_number_gap), kMaxSequenceNumberGap)
235             << "Gap in sequence numbers (" << latest_observed << " -> "
236             << sequence_number << ") too large for SSRC: " << ssrc << ".";
237         seq_numbers->push_back(sequence_number);
238         if (seq_numbers->size() >= kMaxSequenceNumberGap) {
239           seq_numbers->pop_front();
240         }
241       }
242 
243       if (!ssrc_is_rtx_[ssrc]) {
244         MutexLock lock(&mutex_);
245         ValidateTimestampGap(ssrc, timestamp, only_padding);
246 
247         // Wait for media packets on all ssrcs.
248         if (!ssrc_observed_[ssrc] && !only_padding) {
249           ssrc_observed_[ssrc] = true;
250           if (--ssrcs_to_observe_ == 0)
251             observation_complete_.Set();
252         }
253       }
254 
255       return SEND_PACKET;
256     }
257 
258     Action OnSendRtcp(const uint8_t* packet, size_t length) override {
259       test::RtcpPacketParser rtcp_parser;
260       rtcp_parser.Parse(packet, length);
261       if (rtcp_parser.sender_report()->num_packets() > 0) {
262         uint32_t ssrc = rtcp_parser.sender_report()->sender_ssrc();
263         uint32_t rtcp_timestamp = rtcp_parser.sender_report()->rtp_timestamp();
264 
265         MutexLock lock(&mutex_);
266         ValidateTimestampGap(ssrc, rtcp_timestamp, false);
267       }
268       return SEND_PACKET;
269     }
270 
271     SequenceNumberUnwrapper seq_numbers_unwrapper_;
272     std::map<uint32_t, std::list<int64_t>> last_observed_seq_numbers_;
273     std::map<uint32_t, uint32_t> last_observed_timestamp_;
274     std::map<uint32_t, bool> ssrc_is_rtx_;
275 
276     Mutex mutex_;
277     size_t ssrcs_to_observe_ RTC_GUARDED_BY(mutex_);
278     std::map<uint32_t, bool> ssrc_observed_ RTC_GUARDED_BY(mutex_);
279   } observer(use_rtx);
280 
281   std::unique_ptr<test::PacketTransport> send_transport;
282   std::unique_ptr<test::PacketTransport> receive_transport;
283 
284   VideoEncoderConfig one_stream;
285 
286   SendTask(
287       task_queue(), [this, &observer, &send_transport, &receive_transport,
288                      &one_stream, use_rtx]() {
289         CreateCalls();
290 
291         send_transport = std::make_unique<test::PacketTransport>(
292             task_queue(), sender_call_.get(), &observer,
293             test::PacketTransport::kSender, payload_type_map_,
294             std::make_unique<FakeNetworkPipe>(
295                 Clock::GetRealTimeClock(),
296                 std::make_unique<SimulatedNetwork>(
297                     BuiltInNetworkBehaviorConfig())));
298         receive_transport = std::make_unique<test::PacketTransport>(
299             task_queue(), nullptr, &observer, test::PacketTransport::kReceiver,
300             payload_type_map_,
301             std::make_unique<FakeNetworkPipe>(
302                 Clock::GetRealTimeClock(),
303                 std::make_unique<SimulatedNetwork>(
304                     BuiltInNetworkBehaviorConfig())));
305         send_transport->SetReceiver(receiver_call_->Receiver());
306         receive_transport->SetReceiver(sender_call_->Receiver());
307 
308         CreateSendConfig(kNumSimulcastStreams, 0, 0, send_transport.get());
309 
310         if (use_rtx) {
311           for (size_t i = 0; i < kNumSimulcastStreams; ++i) {
312             GetVideoSendConfig()->rtp.rtx.ssrcs.push_back(kSendRtxSsrcs[i]);
313           }
314           GetVideoSendConfig()->rtp.rtx.payload_type = kSendRtxPayloadType;
315         }
316 
317         GetVideoEncoderConfig()->video_stream_factory =
318             rtc::make_ref_counted<VideoStreamFactory>();
319         // Use the same total bitrates when sending a single stream to avoid
320         // lowering the bitrate estimate and requiring a subsequent rampup.
321         one_stream = GetVideoEncoderConfig()->Copy();
322         // one_stream.streams.resize(1);
323         one_stream.number_of_streams = 1;
324         CreateMatchingReceiveConfigs(receive_transport.get());
325 
326         CreateVideoStreams();
327         CreateFrameGeneratorCapturer(30, 1280, 720);
328 
329         Start();
330       });
331 
332   EXPECT_TRUE(observer.Wait())
333       << "Timed out waiting for all SSRCs to send packets.";
334 
335   // Test stream resetting more than once to make sure that the state doesn't
336   // get set once (this could be due to using std::map::insert for instance).
337   for (size_t i = 0; i < 3; ++i) {
338     SendTask(task_queue(), [&]() {
339       DestroyVideoSendStreams();
340 
341       // Re-create VideoSendStream with only one stream.
342       CreateVideoSendStream(one_stream);
343       GetVideoSendStream()->Start();
344       if (provoke_rtcpsr_before_rtp) {
345         // Rapid Resync Request forces sending RTCP Sender Report back.
346         // Using this request speeds up this test because then there is no need
347         // to wait for a second for periodic Sender Report.
348         rtcp::RapidResyncRequest force_send_sr_back_request;
349         rtc::Buffer packet = force_send_sr_back_request.Build();
350         static_cast<webrtc::test::DirectTransport*>(receive_transport.get())
351             ->SendRtcp(packet.data(), packet.size());
352       }
353       CreateFrameGeneratorCapturer(30, 1280, 720);
354     });
355 
356     observer.ResetExpectedSsrcs(1);
357     EXPECT_TRUE(observer.Wait()) << "Timed out waiting for single RTP packet.";
358 
359     // Reconfigure back to use all streams.
360     SendTask(task_queue(), [this]() {
361       GetVideoSendStream()->ReconfigureVideoEncoder(
362           GetVideoEncoderConfig()->Copy());
363     });
364     observer.ResetExpectedSsrcs(kNumSimulcastStreams);
365     EXPECT_TRUE(observer.Wait())
366         << "Timed out waiting for all SSRCs to send packets.";
367 
368     // Reconfigure down to one stream.
369     SendTask(task_queue(), [this, &one_stream]() {
370       GetVideoSendStream()->ReconfigureVideoEncoder(one_stream.Copy());
371     });
372     observer.ResetExpectedSsrcs(1);
373     EXPECT_TRUE(observer.Wait()) << "Timed out waiting for single RTP packet.";
374 
375     // Reconfigure back to use all streams.
376     SendTask(task_queue(), [this]() {
377       GetVideoSendStream()->ReconfigureVideoEncoder(
378           GetVideoEncoderConfig()->Copy());
379     });
380     observer.ResetExpectedSsrcs(kNumSimulcastStreams);
381     EXPECT_TRUE(observer.Wait())
382         << "Timed out waiting for all SSRCs to send packets.";
383   }
384 
385   SendTask(task_queue(), [this, &send_transport, &receive_transport]() {
386     Stop();
387     DestroyStreams();
388     send_transport.reset();
389     receive_transport.reset();
390     DestroyCalls();
391   });
392 }
393 
TEST_F(RtpRtcpEndToEndTest,RestartingSendStreamPreservesRtpState)394 TEST_F(RtpRtcpEndToEndTest, RestartingSendStreamPreservesRtpState) {
395   TestRtpStatePreservation(false, false);
396 }
397 
TEST_F(RtpRtcpEndToEndTest,RestartingSendStreamPreservesRtpStatesWithRtx)398 TEST_F(RtpRtcpEndToEndTest, RestartingSendStreamPreservesRtpStatesWithRtx) {
399   TestRtpStatePreservation(true, false);
400 }
401 
TEST_F(RtpRtcpEndToEndTest,RestartingSendStreamKeepsRtpAndRtcpTimestampsSynced)402 TEST_F(RtpRtcpEndToEndTest,
403        RestartingSendStreamKeepsRtpAndRtcpTimestampsSynced) {
404   TestRtpStatePreservation(true, true);
405 }
406 
407 // See https://bugs.chromium.org/p/webrtc/issues/detail?id=9648.
TEST_F(RtpRtcpEndToEndTest,DISABLED_TestFlexfecRtpStatePreservation)408 TEST_F(RtpRtcpEndToEndTest, DISABLED_TestFlexfecRtpStatePreservation) {
409   class RtpSequenceObserver : public test::RtpRtcpObserver {
410    public:
411     RtpSequenceObserver()
412         : test::RtpRtcpObserver(kDefaultTimeout),
413           num_flexfec_packets_sent_(0) {}
414 
415     void ResetPacketCount() {
416       MutexLock lock(&mutex_);
417       num_flexfec_packets_sent_ = 0;
418     }
419 
420    private:
421     Action OnSendRtp(const uint8_t* packet, size_t length) override {
422       MutexLock lock(&mutex_);
423 
424       RtpPacket rtp_packet;
425       EXPECT_TRUE(rtp_packet.Parse(packet, length));
426       const uint16_t sequence_number = rtp_packet.SequenceNumber();
427       const uint32_t timestamp = rtp_packet.Timestamp();
428       const uint32_t ssrc = rtp_packet.Ssrc();
429 
430       if (ssrc == kVideoSendSsrcs[0] || ssrc == kSendRtxSsrcs[0]) {
431         return SEND_PACKET;
432       }
433       EXPECT_EQ(kFlexfecSendSsrc, ssrc) << "Unknown SSRC sent.";
434 
435       ++num_flexfec_packets_sent_;
436 
437       // If this is the first packet, we have nothing to compare to.
438       if (!last_observed_sequence_number_) {
439         last_observed_sequence_number_.emplace(sequence_number);
440         last_observed_timestamp_.emplace(timestamp);
441 
442         return SEND_PACKET;
443       }
444 
445       // Verify continuity and monotonicity of RTP sequence numbers.
446       EXPECT_EQ(static_cast<uint16_t>(*last_observed_sequence_number_ + 1),
447                 sequence_number);
448       last_observed_sequence_number_.emplace(sequence_number);
449 
450       // Timestamps should be non-decreasing...
451       const bool timestamp_is_same_or_newer =
452           timestamp == *last_observed_timestamp_ ||
453           IsNewerTimestamp(timestamp, *last_observed_timestamp_);
454       EXPECT_TRUE(timestamp_is_same_or_newer);
455       // ...but reasonably close in time.
456       const int k10SecondsInRtpTimestampBase = 10 * kVideoPayloadTypeFrequency;
457       EXPECT_TRUE(IsNewerTimestamp(
458           *last_observed_timestamp_ + k10SecondsInRtpTimestampBase, timestamp));
459       last_observed_timestamp_.emplace(timestamp);
460 
461       // Pass test when enough packets have been let through.
462       if (num_flexfec_packets_sent_ >= 10) {
463         observation_complete_.Set();
464       }
465 
466       return SEND_PACKET;
467     }
468 
469     absl::optional<uint16_t> last_observed_sequence_number_
470         RTC_GUARDED_BY(mutex_);
471     absl::optional<uint32_t> last_observed_timestamp_ RTC_GUARDED_BY(mutex_);
472     size_t num_flexfec_packets_sent_ RTC_GUARDED_BY(mutex_);
473     Mutex mutex_;
474   } observer;
475 
476   static constexpr int kFrameMaxWidth = 320;
477   static constexpr int kFrameMaxHeight = 180;
478   static constexpr int kFrameRate = 15;
479 
480   std::unique_ptr<test::PacketTransport> send_transport;
481   std::unique_ptr<test::PacketTransport> receive_transport;
482   test::FunctionVideoEncoderFactory encoder_factory(
483       []() { return VP8Encoder::Create(); });
484 
485   SendTask(task_queue(), [&]() {
486     CreateCalls();
487 
488     BuiltInNetworkBehaviorConfig lossy_delayed_link;
489     lossy_delayed_link.loss_percent = 2;
490     lossy_delayed_link.queue_delay_ms = 50;
491 
492     send_transport = std::make_unique<test::PacketTransport>(
493         task_queue(), sender_call_.get(), &observer,
494         test::PacketTransport::kSender, payload_type_map_,
495         std::make_unique<FakeNetworkPipe>(
496             Clock::GetRealTimeClock(),
497             std::make_unique<SimulatedNetwork>(lossy_delayed_link)));
498     send_transport->SetReceiver(receiver_call_->Receiver());
499 
500     BuiltInNetworkBehaviorConfig flawless_link;
501     receive_transport = std::make_unique<test::PacketTransport>(
502         task_queue(), nullptr, &observer, test::PacketTransport::kReceiver,
503         payload_type_map_,
504         std::make_unique<FakeNetworkPipe>(
505             Clock::GetRealTimeClock(),
506             std::make_unique<SimulatedNetwork>(flawless_link)));
507     receive_transport->SetReceiver(sender_call_->Receiver());
508 
509     // For reduced flakyness, we use a real VP8 encoder together with NACK
510     // and RTX.
511     const int kNumVideoStreams = 1;
512     const int kNumFlexfecStreams = 1;
513     CreateSendConfig(kNumVideoStreams, 0, kNumFlexfecStreams,
514                      send_transport.get());
515 
516     GetVideoSendConfig()->encoder_settings.encoder_factory = &encoder_factory;
517     GetVideoSendConfig()->rtp.payload_name = "VP8";
518     GetVideoSendConfig()->rtp.payload_type = kVideoSendPayloadType;
519     GetVideoSendConfig()->rtp.nack.rtp_history_ms = kNackRtpHistoryMs;
520     GetVideoSendConfig()->rtp.rtx.ssrcs.push_back(kSendRtxSsrcs[0]);
521     GetVideoSendConfig()->rtp.rtx.payload_type = kSendRtxPayloadType;
522     GetVideoEncoderConfig()->codec_type = kVideoCodecVP8;
523 
524     CreateMatchingReceiveConfigs(receive_transport.get());
525     video_receive_configs_[0].rtp.nack.rtp_history_ms = kNackRtpHistoryMs;
526     video_receive_configs_[0].rtp.rtx_ssrc = kSendRtxSsrcs[0];
527     video_receive_configs_[0]
528         .rtp.rtx_associated_payload_types[kSendRtxPayloadType] =
529         kVideoSendPayloadType;
530 
531     // The matching FlexFEC receive config is not created by
532     // CreateMatchingReceiveConfigs since this is not a test::BaseTest.
533     // Set up the receive config manually instead.
534     FlexfecReceiveStream::Config flexfec_receive_config(
535         receive_transport.get());
536     flexfec_receive_config.payload_type =
537         GetVideoSendConfig()->rtp.flexfec.payload_type;
538     flexfec_receive_config.rtp.remote_ssrc =
539         GetVideoSendConfig()->rtp.flexfec.ssrc;
540     flexfec_receive_config.protected_media_ssrcs =
541         GetVideoSendConfig()->rtp.flexfec.protected_media_ssrcs;
542     flexfec_receive_config.rtp.local_ssrc = kReceiverLocalVideoSsrc;
543     flexfec_receive_config.rtp.transport_cc = true;
544     flexfec_receive_config.rtp.extensions.emplace_back(
545         RtpExtension::kTransportSequenceNumberUri,
546         kTransportSequenceNumberExtensionId);
547     flexfec_receive_configs_.push_back(flexfec_receive_config);
548 
549     CreateFlexfecStreams();
550     CreateVideoStreams();
551 
552     // RTCP might be disabled if the network is "down".
553     sender_call_->SignalChannelNetworkState(MediaType::VIDEO, kNetworkUp);
554     receiver_call_->SignalChannelNetworkState(MediaType::VIDEO, kNetworkUp);
555 
556     CreateFrameGeneratorCapturer(kFrameRate, kFrameMaxWidth, kFrameMaxHeight);
557 
558     Start();
559   });
560 
561   // Initial test.
562   EXPECT_TRUE(observer.Wait()) << "Timed out waiting for packets.";
563 
564   SendTask(task_queue(), [this, &observer]() {
565     // Ensure monotonicity when the VideoSendStream is restarted.
566     Stop();
567     observer.ResetPacketCount();
568     Start();
569   });
570 
571   EXPECT_TRUE(observer.Wait()) << "Timed out waiting for packets.";
572 
573   SendTask(task_queue(), [this, &observer]() {
574     // Ensure monotonicity when the VideoSendStream is recreated.
575     DestroyVideoSendStreams();
576     observer.ResetPacketCount();
577     CreateVideoSendStreams();
578     GetVideoSendStream()->Start();
579     CreateFrameGeneratorCapturer(kFrameRate, kFrameMaxWidth, kFrameMaxHeight);
580   });
581 
582   EXPECT_TRUE(observer.Wait()) << "Timed out waiting for packets.";
583 
584   // Cleanup.
585   SendTask(task_queue(), [this, &send_transport, &receive_transport]() {
586     Stop();
587     DestroyStreams();
588     send_transport.reset();
589     receive_transport.reset();
590     DestroyCalls();
591   });
592 }
593 }  // namespace webrtc
594