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/*
* Copyright 2023 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 "audio/channel_receive.h"
#include "absl/strings/escaping.h"
#include "api/audio_codecs/builtin_audio_decoder_factory.h"
#include "api/crypto/frame_decryptor_interface.h"
#include "api/task_queue/default_task_queue_factory.h"
#include "logging/rtc_event_log/mock/mock_rtc_event_log.h"
#include "modules/audio_device/include/audio_device.h"
#include "modules/audio_device/include/mock_audio_device.h"
#include "modules/rtp_rtcp/source/byte_io.h"
#include "modules/rtp_rtcp/source/rtcp_packet/receiver_report.h"
#include "modules/rtp_rtcp/source/rtcp_packet/report_block.h"
#include "modules/rtp_rtcp/source/rtcp_packet/sdes.h"
#include "modules/rtp_rtcp/source/rtcp_packet/sender_report.h"
#include "modules/rtp_rtcp/source/rtp_packet_received.h"
#include "modules/rtp_rtcp/source/time_util.h"
#include "rtc_base/logging.h"
#include "rtc_base/thread.h"
#include "test/gmock.h"
#include "test/gtest.h"
#include "test/mock_audio_decoder_factory.h"
#include "test/mock_transport.h"
#include "test/time_controller/simulated_time_controller.h"
namespace webrtc {
namespace voe {
namespace {
using ::testing::NiceMock;
using ::testing::NotNull;
using ::testing::Return;
using ::testing::Test;
constexpr uint32_t kLocalSsrc = 1111;
constexpr uint32_t kRemoteSsrc = 2222;
// We run RTP data with 8 kHz PCMA (fixed payload type 8).
constexpr char kPayloadName[] = "PCMA";
constexpr int kPayloadType = 8;
constexpr int kSampleRateHz = 8000;
class ChannelReceiveTest : public Test {
public:
ChannelReceiveTest()
: time_controller_(Timestamp::Seconds(5555)),
audio_device_module_(test::MockAudioDeviceModule::CreateNice()),
audio_decoder_factory_(CreateBuiltinAudioDecoderFactory()) {
ON_CALL(*audio_device_module_, PlayoutDelay).WillByDefault(Return(0));
}
std::unique_ptr<ChannelReceiveInterface> CreateTestChannelReceive() {
CryptoOptions crypto_options;
auto channel = CreateChannelReceive(
time_controller_.GetClock(),
/* neteq_factory= */ nullptr, audio_device_module_.get(), &transport_,
&event_log_, kLocalSsrc, kRemoteSsrc,
/* jitter_buffer_max_packets= */ 0,
/* jitter_buffer_fast_playout= */ false,
/* jitter_buffer_min_delay_ms= */ 0,
/* enable_non_sender_rtt= */ false, audio_decoder_factory_,
/* codec_pair_id= */ absl::nullopt,
/* frame_decryptor_interface= */ nullptr, crypto_options,
/* frame_transformer= */ nullptr);
channel->SetReceiveCodecs(
{{kPayloadType, {kPayloadName, kSampleRateHz, 1}}});
return channel;
}
NtpTime NtpNow() { return time_controller_.GetClock()->CurrentNtpTime(); }
uint32_t RtpNow() {
// Note - the "random" offset of this timestamp is zero.
return rtc::TimeMillis() * 1000 / kSampleRateHz;
}
RtpPacketReceived CreateRtpPacket() {
RtpPacketReceived packet;
packet.set_arrival_time(time_controller_.GetClock()->CurrentTime());
packet.SetTimestamp(RtpNow());
packet.SetSsrc(kLocalSsrc);
packet.SetPayloadType(kPayloadType);
// Packet size should be enough to give at least 10 ms of data.
// For PCMA, that's 80 bytes; this should be enough.
uint8_t* datapos = packet.SetPayloadSize(100);
memset(datapos, 0, 100);
return packet;
}
std::vector<uint8_t> CreateRtcpSenderReport() {
std::vector<uint8_t> packet(1024);
size_t pos = 0;
rtcp::SenderReport report;
report.SetSenderSsrc(kRemoteSsrc);
report.SetNtp(NtpNow());
report.SetRtpTimestamp(RtpNow());
report.SetPacketCount(0);
report.SetOctetCount(0);
report.Create(&packet[0], &pos, packet.size(), nullptr);
// No report blocks.
packet.resize(pos);
return packet;
}
std::vector<uint8_t> CreateRtcpReceiverReport() {
rtcp::ReportBlock block;
block.SetMediaSsrc(kLocalSsrc);
// Middle 32 bits of the NTP timestamp from received SR
block.SetLastSr(CompactNtp(NtpNow()));
block.SetDelayLastSr(0);
rtcp::ReceiverReport report;
report.SetSenderSsrc(kRemoteSsrc);
report.AddReportBlock(block);
std::vector<uint8_t> packet(1024);
size_t pos = 0;
report.Create(&packet[0], &pos, packet.size(), nullptr);
packet.resize(pos);
return packet;
}
void HandleGeneratedRtcp(ChannelReceiveInterface& channel,
rtc::ArrayView<const uint8_t> packet) {
if (packet[1] == rtcp::ReceiverReport::kPacketType) {
// Ignore RR, it requires no response
} else {
RTC_LOG(LS_ERROR) << "Unexpected RTCP packet generated";
RTC_LOG(LS_ERROR) << "Packet content "
<< rtc::hex_encode_with_delimiter(
absl::string_view(
reinterpret_cast<char*>(packet.data()[0]),
packet.size()),
' ');
}
}
int64_t ProbeCaptureStartNtpTime(ChannelReceiveInterface& channel) {
// Computation of the capture_start_ntp_time_ms_ occurs when the
// audio data is pulled, not when it is received. So we need to
// inject an RTP packet, and then fetch its data.
AudioFrame audio_frame;
channel.OnRtpPacket(CreateRtpPacket());
channel.GetAudioFrameWithInfo(kSampleRateHz, &audio_frame);
CallReceiveStatistics stats = channel.GetRTCPStatistics();
return stats.capture_start_ntp_time_ms_;
}
protected:
GlobalSimulatedTimeController time_controller_;
rtc::scoped_refptr<test::MockAudioDeviceModule> audio_device_module_;
rtc::scoped_refptr<AudioDecoderFactory> audio_decoder_factory_;
MockTransport transport_;
NiceMock<MockRtcEventLog> event_log_;
};
TEST_F(ChannelReceiveTest, CreateAndDestroy) {
auto channel = CreateTestChannelReceive();
EXPECT_THAT(channel, NotNull());
}
TEST_F(ChannelReceiveTest, ReceiveReportGeneratedOnTime) {
auto channel = CreateTestChannelReceive();
bool receiver_report_sent = false;
EXPECT_CALL(transport_, SendRtcp)
.WillRepeatedly([&](rtc::ArrayView<const uint8_t> packet) {
if (packet.size() >= 2 &&
packet[1] == rtcp::ReceiverReport::kPacketType) {
receiver_report_sent = true;
}
return true;
});
// RFC 3550 section 6.2 mentions 5 seconds as a reasonable expectation
// for the interval between RTCP packets.
time_controller_.AdvanceTime(TimeDelta::Seconds(5));
EXPECT_TRUE(receiver_report_sent);
}
TEST_F(ChannelReceiveTest, CaptureStartTimeBecomesValid) {
auto channel = CreateTestChannelReceive();
EXPECT_CALL(transport_, SendRtcp)
.WillRepeatedly([&](rtc::ArrayView<const uint8_t> packet) {
HandleGeneratedRtcp(*channel, packet);
return true;
});
// Before any packets are sent, CaptureStartTime is invalid.
EXPECT_EQ(ProbeCaptureStartNtpTime(*channel), -1);
// Must start playout, otherwise packet is discarded.
channel->StartPlayout();
// Send one RTP packet. This causes registration of the SSRC.
channel->OnRtpPacket(CreateRtpPacket());
EXPECT_EQ(ProbeCaptureStartNtpTime(*channel), -1);
// Receive a sender report.
auto rtcp_packet_1 = CreateRtcpSenderReport();
channel->ReceivedRTCPPacket(rtcp_packet_1.data(), rtcp_packet_1.size());
EXPECT_EQ(ProbeCaptureStartNtpTime(*channel), -1);
time_controller_.AdvanceTime(TimeDelta::Seconds(5));
// Receive a receiver report. This is necessary, which is odd.
// Presumably it is because the receiver needs to know the RTT
// before it can compute the capture start NTP time.
// The receiver report must happen before the second sender report.
auto rtcp_rr = CreateRtcpReceiverReport();
channel->ReceivedRTCPPacket(rtcp_rr.data(), rtcp_rr.size());
EXPECT_EQ(ProbeCaptureStartNtpTime(*channel), -1);
// Receive another sender report after 5 seconds.
// This should be enough to establish the capture start NTP time.
auto rtcp_packet_2 = CreateRtcpSenderReport();
channel->ReceivedRTCPPacket(rtcp_packet_2.data(), rtcp_packet_2.size());
EXPECT_NE(ProbeCaptureStartNtpTime(*channel), -1);
}
} // namespace
} // namespace voe
} // namespace webrtc
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