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/*
* Copyright (c) 2021 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/rtp_rtcp/source/packet_sequencer.h"
#include <cstdint>
#include "api/units/time_delta.h"
#include "api/units/timestamp.h"
#include "modules/rtp_rtcp/include/rtp_rtcp_defines.h"
#include "modules/rtp_rtcp/source/rtp_packet_to_send.h"
#include "system_wrappers/include/clock.h"
#include "test/gtest.h"
namespace webrtc {
namespace {
constexpr Timestamp kStartTime = Timestamp::Millis(98765);
constexpr uint32_t kMediaSsrc = 123456;
constexpr uint32_t kRtxSsrc = 123457;
constexpr uint8_t kMediaPayloadType = 42;
constexpr uint16_t kMediaStartSequenceNumber = 123;
constexpr uint16_t kRtxStartSequenceNumber = 234;
constexpr uint16_t kDefaultSequenceNumber = 0x1234;
constexpr uint32_t kStartRtpTimestamp = 798;
class PacketSequencerTest : public ::testing::Test {
public:
PacketSequencerTest()
: clock_(kStartTime),
sequencer_(kMediaSsrc,
kRtxSsrc,
/*require_marker_before_media_padding=*/true,
&clock_) {}
RtpPacketToSend CreatePacket(RtpPacketMediaType type, uint32_t ssrc) {
RtpPacketToSend packet(/*extension_manager=*/nullptr);
packet.set_packet_type(type);
packet.SetSsrc(ssrc);
packet.SetSequenceNumber(kDefaultSequenceNumber);
packet.set_capture_time(clock_.CurrentTime());
packet.SetTimestamp(
kStartRtpTimestamp +
static_cast<uint32_t>(packet.capture_time().ms() - kStartTime.ms()));
return packet;
}
protected:
SimulatedClock clock_;
PacketSequencer sequencer_;
};
TEST_F(PacketSequencerTest, IgnoresMediaSsrcRetransmissions) {
RtpPacketToSend packet =
CreatePacket(RtpPacketMediaType::kRetransmission, kMediaSsrc);
sequencer_.set_media_sequence_number(kMediaStartSequenceNumber);
sequencer_.Sequence(packet);
EXPECT_EQ(packet.SequenceNumber(), kDefaultSequenceNumber);
EXPECT_EQ(sequencer_.media_sequence_number(), kMediaStartSequenceNumber);
}
TEST_F(PacketSequencerTest, SequencesAudio) {
RtpPacketToSend packet = CreatePacket(RtpPacketMediaType::kAudio, kMediaSsrc);
sequencer_.set_media_sequence_number(kMediaStartSequenceNumber);
sequencer_.Sequence(packet);
EXPECT_EQ(packet.SequenceNumber(), kMediaStartSequenceNumber);
EXPECT_EQ(sequencer_.media_sequence_number(), kMediaStartSequenceNumber + 1);
}
TEST_F(PacketSequencerTest, SequencesVideo) {
RtpPacketToSend packet = CreatePacket(RtpPacketMediaType::kVideo, kMediaSsrc);
sequencer_.set_media_sequence_number(kMediaStartSequenceNumber);
sequencer_.Sequence(packet);
EXPECT_EQ(packet.SequenceNumber(), kMediaStartSequenceNumber);
EXPECT_EQ(sequencer_.media_sequence_number(), kMediaStartSequenceNumber + 1);
}
TEST_F(PacketSequencerTest, SequencesUlpFec) {
RtpPacketToSend packet =
CreatePacket(RtpPacketMediaType::kForwardErrorCorrection, kMediaSsrc);
sequencer_.set_media_sequence_number(kMediaStartSequenceNumber);
sequencer_.Sequence(packet);
EXPECT_EQ(packet.SequenceNumber(), kMediaStartSequenceNumber);
EXPECT_EQ(sequencer_.media_sequence_number(), kMediaStartSequenceNumber + 1);
}
TEST_F(PacketSequencerTest, SequencesRtxRetransmissions) {
RtpPacketToSend packet =
CreatePacket(RtpPacketMediaType::kRetransmission, kRtxSsrc);
sequencer_.set_rtx_sequence_number(kRtxStartSequenceNumber);
sequencer_.Sequence(packet);
EXPECT_EQ(packet.SequenceNumber(), kRtxStartSequenceNumber);
EXPECT_EQ(sequencer_.rtx_sequence_number(), kRtxStartSequenceNumber + 1);
}
TEST_F(PacketSequencerTest, ProhibitsPaddingWithinVideoFrame) {
// Send a video packet with the marker bit set to false (indicating it is not
// the last packet of a frame).
RtpPacketToSend media_packet =
CreatePacket(RtpPacketMediaType::kVideo, kMediaSsrc);
media_packet.SetPayloadType(kMediaPayloadType);
media_packet.SetMarker(false);
sequencer_.Sequence(media_packet);
// Sending padding on the media SSRC should not be allowed at this point.
EXPECT_FALSE(sequencer_.CanSendPaddingOnMediaSsrc());
// Send a video packet with marker set to true, padding should be allowed
// again.
media_packet.SetMarker(true);
sequencer_.Sequence(media_packet);
EXPECT_TRUE(sequencer_.CanSendPaddingOnMediaSsrc());
}
TEST_F(PacketSequencerTest, AllowsPaddingAtAnyTimeIfSoConfigured) {
PacketSequencer packet_sequencer(
kMediaSsrc, kRtxSsrc,
/*require_marker_before_media_padding=*/false, &clock_);
// Send an audio packet with the marker bit set to false.
RtpPacketToSend media_packet =
CreatePacket(RtpPacketMediaType::kAudio, kMediaSsrc);
media_packet.SetPayloadType(kMediaPayloadType);
media_packet.SetMarker(false);
packet_sequencer.Sequence(media_packet);
// Sending padding on the media SSRC should be allowed despite no marker bit.
EXPECT_TRUE(packet_sequencer.CanSendPaddingOnMediaSsrc());
}
TEST_F(PacketSequencerTest, UpdatesPaddingBasedOnLastMediaPacket) {
// First send a media packet.
RtpPacketToSend media_packet =
CreatePacket(RtpPacketMediaType::kVideo, kMediaSsrc);
media_packet.SetPayloadType(kMediaPayloadType);
media_packet.SetMarker(true);
// Advance time so current time doesn't exactly match timestamp.
clock_.AdvanceTime(TimeDelta::Millis(5));
sequencer_.set_media_sequence_number(kMediaStartSequenceNumber);
sequencer_.Sequence(media_packet);
// Next send a padding packet and verify the media packet's timestamps and
// payload type is transferred to the padding packet.
RtpPacketToSend padding_packet =
CreatePacket(RtpPacketMediaType::kPadding, kMediaSsrc);
padding_packet.SetPadding(/*padding_size=*/100);
sequencer_.Sequence(padding_packet);
EXPECT_EQ(padding_packet.SequenceNumber(), kMediaStartSequenceNumber + 1);
EXPECT_EQ(padding_packet.PayloadType(), kMediaPayloadType);
EXPECT_EQ(padding_packet.Timestamp(), media_packet.Timestamp());
EXPECT_EQ(padding_packet.capture_time(), media_packet.capture_time());
}
TEST_F(PacketSequencerTest, UpdatesPaddingBasedOnLastRedPacket) {
// First send a media packet.
RtpPacketToSend media_packet =
CreatePacket(RtpPacketMediaType::kVideo, kMediaSsrc);
media_packet.SetPayloadType(kMediaPayloadType);
// Simulate a packet with RED encapsulation;
media_packet.set_is_red(true);
uint8_t* payload_buffer = media_packet.SetPayloadSize(1);
payload_buffer[0] = kMediaPayloadType + 1;
media_packet.SetMarker(true);
// Advance time so current time doesn't exactly match timestamp.
clock_.AdvanceTime(TimeDelta::Millis(5));
sequencer_.set_media_sequence_number(kMediaStartSequenceNumber);
sequencer_.Sequence(media_packet);
// Next send a padding packet and verify the media packet's timestamps and
// payload type is transferred to the padding packet.
RtpPacketToSend padding_packet =
CreatePacket(RtpPacketMediaType::kPadding, kMediaSsrc);
padding_packet.SetPadding(100);
sequencer_.Sequence(padding_packet);
EXPECT_EQ(padding_packet.SequenceNumber(), kMediaStartSequenceNumber + 1);
EXPECT_EQ(padding_packet.PayloadType(), kMediaPayloadType + 1);
EXPECT_EQ(padding_packet.Timestamp(), media_packet.Timestamp());
EXPECT_EQ(padding_packet.capture_time(), media_packet.capture_time());
}
TEST_F(PacketSequencerTest, DoesNotUpdateFieldsOnPayloadPadding) {
// First send a media packet.
RtpPacketToSend media_packet =
CreatePacket(RtpPacketMediaType::kVideo, kMediaSsrc);
media_packet.SetPayloadType(kMediaPayloadType);
media_packet.SetMarker(true);
// Advance time so current time doesn't exactly match timestamp.
clock_.AdvanceTime(TimeDelta::Millis(5));
sequencer_.set_media_sequence_number(kMediaStartSequenceNumber);
sequencer_.Sequence(media_packet);
// Simulate a payload padding packet on the RTX SSRC.
RtpPacketToSend padding_packet =
CreatePacket(RtpPacketMediaType::kPadding, kRtxSsrc);
padding_packet.SetPayloadSize(100);
padding_packet.SetPayloadType(kMediaPayloadType + 1);
padding_packet.SetTimestamp(kStartRtpTimestamp + 1);
padding_packet.set_capture_time(kStartTime + TimeDelta::Millis(1));
sequencer_.set_rtx_sequence_number(kRtxStartSequenceNumber);
sequencer_.Sequence(padding_packet);
// The sequence number should be updated, but timestamps kept.
EXPECT_EQ(padding_packet.SequenceNumber(), kRtxStartSequenceNumber);
EXPECT_EQ(padding_packet.PayloadType(), kMediaPayloadType + 1);
EXPECT_EQ(padding_packet.Timestamp(), kStartRtpTimestamp + 1);
EXPECT_EQ(padding_packet.capture_time(), kStartTime + TimeDelta::Millis(1));
}
TEST_F(PacketSequencerTest, UpdatesRtxPaddingBasedOnLastMediaPacket) {
constexpr uint32_t kTimestampTicksPerMs = 90;
// First send a media packet.
RtpPacketToSend media_packet =
CreatePacket(RtpPacketMediaType::kVideo, kMediaSsrc);
media_packet.SetPayloadType(kMediaPayloadType);
media_packet.SetMarker(true);
sequencer_.set_media_sequence_number(kMediaStartSequenceNumber);
sequencer_.Sequence(media_packet);
// Advance time, this time delta will be used to interpolate padding
// timestamps.
constexpr TimeDelta kTimeDelta = TimeDelta::Millis(10);
clock_.AdvanceTime(kTimeDelta);
RtpPacketToSend padding_packet =
CreatePacket(RtpPacketMediaType::kPadding, kRtxSsrc);
padding_packet.SetPadding(100);
padding_packet.SetPayloadType(kMediaPayloadType + 1);
sequencer_.set_rtx_sequence_number(kRtxStartSequenceNumber);
sequencer_.Sequence(padding_packet);
// Assigned RTX sequence number, but payload type unchanged in this case.
EXPECT_EQ(padding_packet.SequenceNumber(), kRtxStartSequenceNumber);
EXPECT_EQ(padding_packet.PayloadType(), kMediaPayloadType + 1);
// Timestamps are offset realtive to last media packet.
EXPECT_EQ(
padding_packet.Timestamp(),
media_packet.Timestamp() + (kTimeDelta.ms() * kTimestampTicksPerMs));
EXPECT_EQ(padding_packet.capture_time(),
media_packet.capture_time() + kTimeDelta);
}
} // namespace
} // namespace webrtc
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