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/*
* Copyright 2019 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 <algorithm>
#include <iterator>
#include <map>
#include <memory>
#include <string>
#include <utility>
#include <vector>
#include "absl/algorithm/container.h"
#include "absl/strings/match.h"
#include "absl/strings/string_view.h"
#include "api/audio/audio_device.h"
#include "api/audio/audio_mixer.h"
#include "api/audio/audio_processing.h"
#include "api/audio_codecs/builtin_audio_decoder_factory.h"
#include "api/audio_codecs/builtin_audio_encoder_factory.h"
#include "api/audio_codecs/opus_audio_decoder_factory.h"
#include "api/audio_codecs/opus_audio_encoder_factory.h"
#include "api/create_peerconnection_factory.h"
#include "api/jsep.h"
#include "api/media_types.h"
#include "api/peer_connection_interface.h"
#include "api/rtc_error.h"
#include "api/rtp_parameters.h"
#include "api/rtp_sender_interface.h"
#include "api/rtp_transceiver_direction.h"
#include "api/rtp_transceiver_interface.h"
#include "api/scoped_refptr.h"
#include "api/uma_metrics.h"
#include "api/video/video_codec_constants.h"
#include "api/video_codecs/video_decoder_factory_template.h"
#include "api/video_codecs/video_decoder_factory_template_dav1d_adapter.h"
#include "api/video_codecs/video_decoder_factory_template_libvpx_vp8_adapter.h"
#include "api/video_codecs/video_decoder_factory_template_libvpx_vp9_adapter.h"
#include "api/video_codecs/video_decoder_factory_template_open_h264_adapter.h"
#include "api/video_codecs/video_encoder_factory_template.h"
#include "api/video_codecs/video_encoder_factory_template_libaom_av1_adapter.h"
#include "api/video_codecs/video_encoder_factory_template_libvpx_vp8_adapter.h"
#include "api/video_codecs/video_encoder_factory_template_libvpx_vp9_adapter.h"
#include "api/video_codecs/video_encoder_factory_template_open_h264_adapter.h"
#include "media/base/media_constants.h"
#include "media/base/rid_description.h"
#include "media/base/stream_params.h"
#include "pc/channel_interface.h"
#include "pc/peer_connection_wrapper.h"
#include "pc/sdp_utils.h"
#include "pc/session_description.h"
#include "pc/simulcast_description.h"
#include "pc/test/fake_audio_capture_module.h"
#include "pc/test/mock_peer_connection_observers.h"
#include "pc/test/simulcast_layer_util.h"
#include "rtc_base/checks.h"
#include "rtc_base/gunit.h"
#include "rtc_base/strings/string_builder.h"
#include "rtc_base/thread.h"
#include "rtc_base/unique_id_generator.h"
#include "system_wrappers/include/metrics.h"
#include "test/gmock.h"
#include "test/gtest.h"
using ::testing::Contains;
using ::testing::Each;
using ::testing::ElementsAre;
using ::testing::ElementsAreArray;
using ::testing::Eq;
using ::testing::Field;
using ::testing::IsEmpty;
using ::testing::Le;
using ::testing::Ne;
using ::testing::Pair;
using ::testing::Property;
using ::testing::SizeIs;
using ::testing::StartsWith;
using cricket::MediaContentDescription;
using cricket::RidDescription;
using cricket::SimulcastDescription;
using cricket::SimulcastLayer;
using cricket::StreamParams;
namespace webrtc {
class PeerConnectionSimulcastTests : public ::testing::Test {
public:
PeerConnectionSimulcastTests()
: pc_factory_(CreatePeerConnectionFactory(
rtc::Thread::Current(),
rtc::Thread::Current(),
rtc::Thread::Current(),
FakeAudioCaptureModule::Create(),
CreateBuiltinAudioEncoderFactory(),
CreateBuiltinAudioDecoderFactory(),
std::make_unique<
VideoEncoderFactoryTemplate<LibvpxVp8EncoderTemplateAdapter,
LibvpxVp9EncoderTemplateAdapter,
OpenH264EncoderTemplateAdapter,
LibaomAv1EncoderTemplateAdapter>>(),
std::make_unique<
VideoDecoderFactoryTemplate<LibvpxVp8DecoderTemplateAdapter,
LibvpxVp9DecoderTemplateAdapter,
OpenH264DecoderTemplateAdapter,
Dav1dDecoderTemplateAdapter>>(),
nullptr,
nullptr)) {}
rtc::scoped_refptr<PeerConnectionInterface> CreatePeerConnection(
MockPeerConnectionObserver* observer) {
PeerConnectionInterface::RTCConfiguration config;
config.sdp_semantics = SdpSemantics::kUnifiedPlan;
PeerConnectionDependencies pcd(observer);
auto result =
pc_factory_->CreatePeerConnectionOrError(config, std::move(pcd));
EXPECT_TRUE(result.ok());
observer->SetPeerConnectionInterface(result.value().get());
return result.MoveValue();
}
std::unique_ptr<PeerConnectionWrapper> CreatePeerConnectionWrapper() {
auto observer = std::make_unique<MockPeerConnectionObserver>();
auto pc = CreatePeerConnection(observer.get());
return std::make_unique<PeerConnectionWrapper>(pc_factory_, pc,
std::move(observer));
}
void ExchangeOfferAnswer(PeerConnectionWrapper* local,
PeerConnectionWrapper* remote,
const std::vector<SimulcastLayer>& answer_layers) {
auto offer = local->CreateOfferAndSetAsLocal();
// Remove simulcast as the second peer connection won't support it.
RemoveSimulcast(offer.get());
std::string err;
EXPECT_TRUE(remote->SetRemoteDescription(std::move(offer), &err)) << err;
auto answer = remote->CreateAnswerAndSetAsLocal();
// Setup the answer to look like a server response.
auto mcd_answer = answer->description()->contents()[0].media_description();
auto& receive_layers = mcd_answer->simulcast_description().receive_layers();
for (const SimulcastLayer& layer : answer_layers) {
receive_layers.AddLayer(layer);
}
EXPECT_TRUE(local->SetRemoteDescription(std::move(answer), &err)) << err;
}
rtc::scoped_refptr<RtpTransceiverInterface> AddTransceiver(
PeerConnectionWrapper* pc,
const std::vector<SimulcastLayer>& layers,
cricket::MediaType media_type = cricket::MEDIA_TYPE_VIDEO) {
auto init = CreateTransceiverInit(layers);
return pc->AddTransceiver(media_type, init);
}
void AddRequestToReceiveSimulcast(const std::vector<SimulcastLayer>& layers,
SessionDescriptionInterface* sd) {
auto mcd = sd->description()->contents()[0].media_description();
SimulcastDescription simulcast;
auto& receive_layers = simulcast.receive_layers();
for (const SimulcastLayer& layer : layers) {
receive_layers.AddLayer(layer);
}
mcd->set_simulcast_description(simulcast);
}
void ValidateTransceiverParameters(
rtc::scoped_refptr<RtpTransceiverInterface> transceiver,
const std::vector<SimulcastLayer>& layers) {
auto parameters = transceiver->sender()->GetParameters();
std::vector<SimulcastLayer> result_layers;
absl::c_transform(parameters.encodings, std::back_inserter(result_layers),
[](const RtpEncodingParameters& encoding) {
return SimulcastLayer(encoding.rid, !encoding.active);
});
EXPECT_THAT(result_layers, ElementsAreArray(layers));
}
private:
rtc::scoped_refptr<PeerConnectionFactoryInterface> pc_factory_;
};
// Validates that RIDs are supported arguments when adding a transceiver.
TEST_F(PeerConnectionSimulcastTests, CanCreateTransceiverWithRid) {
auto pc = CreatePeerConnectionWrapper();
auto layers = CreateLayers({"f"}, true);
auto transceiver = AddTransceiver(pc.get(), layers);
ASSERT_TRUE(transceiver);
auto parameters = transceiver->sender()->GetParameters();
// Single RID should be removed.
EXPECT_THAT(parameters.encodings,
ElementsAre(Field("rid", &RtpEncodingParameters::rid, Eq(""))));
}
TEST_F(PeerConnectionSimulcastTests, CanCreateTransceiverWithSimulcast) {
auto pc = CreatePeerConnectionWrapper();
auto layers = CreateLayers({"f", "h", "q"}, true);
auto transceiver = AddTransceiver(pc.get(), layers);
ASSERT_TRUE(transceiver);
ValidateTransceiverParameters(transceiver, layers);
}
TEST_F(PeerConnectionSimulcastTests, RidsAreAutogeneratedIfNotProvided) {
auto pc = CreatePeerConnectionWrapper();
auto init = CreateTransceiverInit(CreateLayers({"f", "h", "q"}, true));
for (RtpEncodingParameters& parameters : init.send_encodings) {
parameters.rid = "";
}
auto transceiver = pc->AddTransceiver(cricket::MEDIA_TYPE_VIDEO, init);
auto parameters = transceiver->sender()->GetParameters();
ASSERT_EQ(3u, parameters.encodings.size());
EXPECT_THAT(parameters.encodings,
Each(Field("rid", &RtpEncodingParameters::rid, Ne(""))));
}
// Validates that an error is returned when there is a mix of supplied and not
// supplied RIDs in a call to AddTransceiver.
TEST_F(PeerConnectionSimulcastTests, MustSupplyAllOrNoRidsInSimulcast) {
auto pc_wrapper = CreatePeerConnectionWrapper();
auto pc = pc_wrapper->pc();
// Cannot create a layer with empty RID. Remove the RID after init is created.
auto layers = CreateLayers({"f", "h", "remove"}, true);
auto init = CreateTransceiverInit(layers);
init.send_encodings[2].rid = "";
auto error = pc->AddTransceiver(cricket::MEDIA_TYPE_VIDEO, init);
EXPECT_EQ(RTCErrorType::INVALID_PARAMETER, error.error().type());
}
// Validates that an error is returned when illegal RIDs are supplied.
TEST_F(PeerConnectionSimulcastTests, ChecksForIllegalRidValues) {
auto pc_wrapper = CreatePeerConnectionWrapper();
auto pc = pc_wrapper->pc();
auto layers = CreateLayers({"f", "h", "~q"}, true);
auto init = CreateTransceiverInit(layers);
auto error = pc->AddTransceiver(cricket::MEDIA_TYPE_VIDEO, init);
EXPECT_EQ(RTCErrorType::INVALID_PARAMETER, error.error().type());
}
// Validates that a single RID is removed from the encoding layer.
TEST_F(PeerConnectionSimulcastTests, SingleRidIsRemovedFromSessionDescription) {
auto pc = CreatePeerConnectionWrapper();
auto transceiver = AddTransceiver(pc.get(), CreateLayers({"1"}, true));
auto offer = pc->CreateOfferAndSetAsLocal();
ASSERT_TRUE(offer);
auto contents = offer->description()->contents();
ASSERT_EQ(1u, contents.size());
EXPECT_THAT(contents[0].media_description()->streams(),
ElementsAre(Property(&StreamParams::has_rids, false)));
}
TEST_F(PeerConnectionSimulcastTests, SimulcastLayersRemovedFromTail) {
static_assert(
kMaxSimulcastStreams < 8,
"Test assumes that the platform does not allow 8 simulcast layers");
auto pc = CreatePeerConnectionWrapper();
auto layers = CreateLayers({"1", "2", "3", "4", "5", "6", "7", "8"}, true);
std::vector<SimulcastLayer> expected_layers;
std::copy_n(layers.begin(), kMaxSimulcastStreams,
std::back_inserter(expected_layers));
auto transceiver = AddTransceiver(pc.get(), layers);
ValidateTransceiverParameters(transceiver, expected_layers);
}
// Checks that an offfer to send simulcast contains a SimulcastDescription.
TEST_F(PeerConnectionSimulcastTests, SimulcastAppearsInSessionDescription) {
auto pc = CreatePeerConnectionWrapper();
std::vector<std::string> rids({"f", "h", "q"});
auto layers = CreateLayers(rids, true);
auto transceiver = AddTransceiver(pc.get(), layers);
auto offer = pc->CreateOffer();
ASSERT_TRUE(offer);
auto contents = offer->description()->contents();
ASSERT_EQ(1u, contents.size());
auto content = contents[0];
auto mcd = content.media_description();
ASSERT_TRUE(mcd->HasSimulcast());
auto simulcast = mcd->simulcast_description();
EXPECT_THAT(simulcast.receive_layers(), IsEmpty());
// The size is validated separately because GetAllLayers() flattens the list.
EXPECT_THAT(simulcast.send_layers(), SizeIs(3));
std::vector<SimulcastLayer> result = simulcast.send_layers().GetAllLayers();
EXPECT_THAT(result, ElementsAreArray(layers));
auto streams = mcd->streams();
ASSERT_EQ(1u, streams.size());
auto stream = streams[0];
EXPECT_FALSE(stream.has_ssrcs());
EXPECT_TRUE(stream.has_rids());
std::vector<std::string> result_rids;
absl::c_transform(stream.rids(), std::back_inserter(result_rids),
[](const RidDescription& rid) { return rid.rid; });
EXPECT_THAT(result_rids, ElementsAreArray(rids));
}
// Checks that Simulcast layers propagate to the sender parameters.
TEST_F(PeerConnectionSimulcastTests, SimulcastLayersAreSetInSender) {
auto local = CreatePeerConnectionWrapper();
auto remote = CreatePeerConnectionWrapper();
auto layers = CreateLayers({"f", "h", "q"}, true);
auto transceiver = AddTransceiver(local.get(), layers);
auto offer = local->CreateOfferAndSetAsLocal();
{
SCOPED_TRACE("after create offer");
ValidateTransceiverParameters(transceiver, layers);
}
// Remove simulcast as the second peer connection won't support it.
auto simulcast = RemoveSimulcast(offer.get());
std::string error;
EXPECT_TRUE(remote->SetRemoteDescription(std::move(offer), &error)) << error;
auto answer = remote->CreateAnswerAndSetAsLocal();
// Setup an answer that mimics a server accepting simulcast.
auto mcd_answer = answer->description()->contents()[0].media_description();
mcd_answer->mutable_streams().clear();
auto simulcast_layers = simulcast.send_layers().GetAllLayers();
auto& receive_layers = mcd_answer->simulcast_description().receive_layers();
for (const auto& layer : simulcast_layers) {
receive_layers.AddLayer(layer);
}
EXPECT_TRUE(local->SetRemoteDescription(std::move(answer), &error)) << error;
{
SCOPED_TRACE("after set remote");
ValidateTransceiverParameters(transceiver, layers);
}
}
// Checks that paused Simulcast layers propagate to the sender parameters.
TEST_F(PeerConnectionSimulcastTests, PausedSimulcastLayersAreDisabledInSender) {
auto local = CreatePeerConnectionWrapper();
auto remote = CreatePeerConnectionWrapper();
auto layers = CreateLayers({"f", "h", "q"}, {true, false, true});
auto server_layers = CreateLayers({"f", "h", "q"}, {true, false, false});
RTC_DCHECK_EQ(layers.size(), server_layers.size());
auto transceiver = AddTransceiver(local.get(), layers);
auto offer = local->CreateOfferAndSetAsLocal();
{
SCOPED_TRACE("after create offer");
ValidateTransceiverParameters(transceiver, layers);
}
// Remove simulcast as the second peer connection won't support it.
RemoveSimulcast(offer.get());
std::string error;
EXPECT_TRUE(remote->SetRemoteDescription(std::move(offer), &error)) << error;
auto answer = remote->CreateAnswerAndSetAsLocal();
// Setup an answer that mimics a server accepting simulcast.
auto mcd_answer = answer->description()->contents()[0].media_description();
mcd_answer->mutable_streams().clear();
auto& receive_layers = mcd_answer->simulcast_description().receive_layers();
for (const SimulcastLayer& layer : server_layers) {
receive_layers.AddLayer(layer);
}
EXPECT_TRUE(local->SetRemoteDescription(std::move(answer), &error)) << error;
{
SCOPED_TRACE("after set remote");
ValidateTransceiverParameters(transceiver, server_layers);
}
}
// Checks that when Simulcast is not supported by the remote party, then all
// the layers (except the first) are removed.
TEST_F(PeerConnectionSimulcastTests, SimulcastRejectedRemovesExtraLayers) {
auto local = CreatePeerConnectionWrapper();
auto remote = CreatePeerConnectionWrapper();
auto layers = CreateLayers({"1", "2", "3", "4"}, true);
auto transceiver = AddTransceiver(local.get(), layers);
ExchangeOfferAnswer(local.get(), remote.get(), {});
auto parameters = transceiver->sender()->GetParameters();
// Should only have the first layer.
EXPECT_THAT(parameters.encodings,
ElementsAre(Field("rid", &RtpEncodingParameters::rid, Eq("1"))));
}
// Checks that if Simulcast is supported by remote party, but some layers are
// rejected, then only rejected layers are removed from the sender.
TEST_F(PeerConnectionSimulcastTests, RejectedSimulcastLayersAreDeactivated) {
auto local = CreatePeerConnectionWrapper();
auto remote = CreatePeerConnectionWrapper();
auto layers = CreateLayers({"1", "2", "3"}, true);
auto expected_layers = CreateLayers({"2", "3"}, true);
auto transceiver = AddTransceiver(local.get(), layers);
auto offer = local->CreateOfferAndSetAsLocal();
{
SCOPED_TRACE("after create offer");
ValidateTransceiverParameters(transceiver, layers);
}
// Remove simulcast as the second peer connection won't support it.
auto removed_simulcast = RemoveSimulcast(offer.get());
std::string error;
EXPECT_TRUE(remote->SetRemoteDescription(std::move(offer), &error)) << error;
auto answer = remote->CreateAnswerAndSetAsLocal();
auto mcd_answer = answer->description()->contents()[0].media_description();
// Setup the answer to look like a server response.
// Remove one of the layers to reject it in the answer.
auto simulcast_layers = removed_simulcast.send_layers().GetAllLayers();
simulcast_layers.erase(simulcast_layers.begin());
auto& receive_layers = mcd_answer->simulcast_description().receive_layers();
for (const auto& layer : simulcast_layers) {
receive_layers.AddLayer(layer);
}
ASSERT_TRUE(mcd_answer->HasSimulcast());
EXPECT_TRUE(local->SetRemoteDescription(std::move(answer), &error)) << error;
{
SCOPED_TRACE("after set remote");
ValidateTransceiverParameters(transceiver, expected_layers);
}
}
// Checks that simulcast is set up correctly when the server sends an offer
// requesting to receive simulcast.
TEST_F(PeerConnectionSimulcastTests, ServerSendsOfferToReceiveSimulcast) {
auto local = CreatePeerConnectionWrapper();
auto remote = CreatePeerConnectionWrapper();
auto layers = CreateLayers({"f", "h", "q"}, true);
AddTransceiver(local.get(), layers);
auto offer = local->CreateOfferAndSetAsLocal();
// Remove simulcast as a sender and set it up as a receiver.
RemoveSimulcast(offer.get());
AddRequestToReceiveSimulcast(layers, offer.get());
std::string error;
EXPECT_TRUE(remote->SetRemoteDescription(std::move(offer), &error)) << error;
auto transceiver = remote->pc()->GetTransceivers()[0];
transceiver->SetDirectionWithError(RtpTransceiverDirection::kSendRecv);
EXPECT_TRUE(remote->CreateAnswerAndSetAsLocal());
ValidateTransceiverParameters(transceiver, layers);
}
// Checks that SetRemoteDescription doesn't attempt to associate a transceiver
// when simulcast is requested by the server.
TEST_F(PeerConnectionSimulcastTests, TransceiverIsNotRecycledWithSimulcast) {
auto local = CreatePeerConnectionWrapper();
auto remote = CreatePeerConnectionWrapper();
auto layers = CreateLayers({"f", "h", "q"}, true);
AddTransceiver(local.get(), layers);
auto offer = local->CreateOfferAndSetAsLocal();
// Remove simulcast as a sender and set it up as a receiver.
RemoveSimulcast(offer.get());
AddRequestToReceiveSimulcast(layers, offer.get());
// Call AddTrack so that a transceiver is created.
remote->AddVideoTrack("fake_track");
std::string error;
EXPECT_TRUE(remote->SetRemoteDescription(std::move(offer), &error)) << error;
auto transceivers = remote->pc()->GetTransceivers();
ASSERT_EQ(2u, transceivers.size());
auto transceiver = transceivers[1];
transceiver->SetDirectionWithError(RtpTransceiverDirection::kSendRecv);
EXPECT_TRUE(remote->CreateAnswerAndSetAsLocal());
ValidateTransceiverParameters(transceiver, layers);
}
// Checks that if the number of layers changes during negotiation, then any
// outstanding get/set parameters transaction is invalidated.
TEST_F(PeerConnectionSimulcastTests, ParametersAreInvalidatedWhenLayersChange) {
auto local = CreatePeerConnectionWrapper();
auto remote = CreatePeerConnectionWrapper();
auto layers = CreateLayers({"1", "2", "3"}, true);
auto transceiver = AddTransceiver(local.get(), layers);
auto parameters = transceiver->sender()->GetParameters();
ASSERT_EQ(3u, parameters.encodings.size());
// Response will reject simulcast altogether.
ExchangeOfferAnswer(local.get(), remote.get(), {});
auto result = transceiver->sender()->SetParameters(parameters);
EXPECT_EQ(RTCErrorType::INVALID_STATE, result.type());
}
// Checks that even though negotiation modifies the sender's parameters, an
// outstanding get/set parameters transaction is not invalidated.
// This test negotiates twice because initial parameters before negotiation
// is missing critical information and cannot be set on the sender.
TEST_F(PeerConnectionSimulcastTests,
NegotiationDoesNotInvalidateParameterTransactions) {
auto local = CreatePeerConnectionWrapper();
auto remote = CreatePeerConnectionWrapper();
auto layers = CreateLayers({"1", "2", "3"}, true);
auto expected_layers = CreateLayers({"1", "2", "3"}, false);
auto transceiver = AddTransceiver(local.get(), layers);
ExchangeOfferAnswer(local.get(), remote.get(), expected_layers);
// Verify that negotiation does not invalidate the parameters.
auto parameters = transceiver->sender()->GetParameters();
ExchangeOfferAnswer(local.get(), remote.get(), expected_layers);
auto result = transceiver->sender()->SetParameters(parameters);
EXPECT_TRUE(result.ok());
ValidateTransceiverParameters(transceiver, expected_layers);
}
// Tests that a simulcast answer is rejected if the RID extension is not
// negotiated.
TEST_F(PeerConnectionSimulcastTests, NegotiationDoesNotHaveRidExtensionFails) {
auto local = CreatePeerConnectionWrapper();
auto remote = CreatePeerConnectionWrapper();
auto layers = CreateLayers({"1", "2", "3"}, true);
auto expected_layers = CreateLayers({"1"}, true);
auto transceiver = AddTransceiver(local.get(), layers);
auto offer = local->CreateOfferAndSetAsLocal();
// Remove simulcast as the second peer connection won't support it.
RemoveSimulcast(offer.get());
std::string err;
EXPECT_TRUE(remote->SetRemoteDescription(std::move(offer), &err)) << err;
auto answer = remote->CreateAnswerAndSetAsLocal();
// Setup the answer to look like a server response.
// Drop the RID header extension.
auto mcd_answer = answer->description()->contents()[0].media_description();
auto& receive_layers = mcd_answer->simulcast_description().receive_layers();
for (const SimulcastLayer& layer : layers) {
receive_layers.AddLayer(layer);
}
cricket::RtpHeaderExtensions extensions;
for (auto extension : mcd_answer->rtp_header_extensions()) {
if (extension.uri != RtpExtension::kRidUri) {
extensions.push_back(extension);
}
}
mcd_answer->set_rtp_header_extensions(extensions);
EXPECT_EQ(layers.size(), mcd_answer->simulcast_description()
.receive_layers()
.GetAllLayers()
.size());
EXPECT_FALSE(local->SetRemoteDescription(std::move(answer), &err)) << err;
}
TEST_F(PeerConnectionSimulcastTests, SimulcastAudioRejected) {
auto local = CreatePeerConnectionWrapper();
auto remote = CreatePeerConnectionWrapper();
auto layers = CreateLayers({"1", "2", "3", "4"}, true);
auto transceiver =
AddTransceiver(local.get(), layers, cricket::MEDIA_TYPE_AUDIO);
// Should only have the first layer.
auto parameters = transceiver->sender()->GetParameters();
EXPECT_EQ(1u, parameters.encodings.size());
EXPECT_THAT(parameters.encodings,
ElementsAre(Field("rid", &RtpEncodingParameters::rid, Eq(""))));
ExchangeOfferAnswer(local.get(), remote.get(), {});
// Still have a single layer after negotiation
parameters = transceiver->sender()->GetParameters();
EXPECT_EQ(1u, parameters.encodings.size());
EXPECT_THAT(parameters.encodings,
ElementsAre(Field("rid", &RtpEncodingParameters::rid, Eq(""))));
}
// Check that modifying the offer to remove simulcast and at the same
// time leaving in a RID line does not cause an exception.
TEST_F(PeerConnectionSimulcastTests, SimulcastSldModificationRejected) {
auto local = CreatePeerConnectionWrapper();
auto remote = CreatePeerConnectionWrapper();
auto layers = CreateLayers({"1", "2", "3"}, true);
AddTransceiver(local.get(), layers);
auto offer = local->CreateOffer();
std::string as_string;
EXPECT_TRUE(offer->ToString(&as_string));
auto simulcast_marker = "a=rid:3 send\r\na=simulcast:send 1;2;3\r\n";
auto pos = as_string.find(simulcast_marker);
EXPECT_NE(pos, std::string::npos);
as_string.erase(pos, strlen(simulcast_marker));
SdpParseError parse_error;
auto modified_offer =
CreateSessionDescription(SdpType::kOffer, as_string, &parse_error);
EXPECT_TRUE(modified_offer);
EXPECT_TRUE(local->SetLocalDescription(std::move(modified_offer)));
}
} // namespace webrtc