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For ossrs#3167: WebRTC: Refine sequence jitter algorithm. v4.0.266
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@winlinvip @johzzy
winlinvip authored and johzzy committed Apr 18, 2023
1 parent ea288de commit d85c757
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5 changes: 5 additions & 0 deletions trunk/doc/CHANGELOG.md
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Expand Up @@ -63,6 +63,11 @@ The changelog for SRS.

## SRS 4.0 Changelog

* v4.0, 2022-09-27, For [#3167](https://github.com/ossrs/srs/issues/3167): WebRTC: Refine sequence jitter algorithm. v4.0.266
* v4.0, 2022-09-16, For [#3179](https://github.com/ossrs/srs/issues/3179): WebRTC: Make sure the same m-lines order for offer and answer. v4.0.265
* v4.0, 2022-09-09, For [#3174](https://github.com/ossrs/srs/issues/3174): WebRTC: Support Unity to publish or play stream. v4.0.264
* v4.0, 2022-09-09, Fix [#3093](https://github.com/ossrs/srs/issues/3093): WebRTC: Ignore unknown fmtp for h.264. v4.0.263
* v4.0, 2022-09-06, Fix [#3170](https://github.com/ossrs/srs/issues/3170): WebRTC: Support WHIP(WebRTC-HTTP ingestion protocol). v4.0.262
* v4.0, 2022-09-03, Fix HTTP url parsing bug. v4.0.261
* v4.0, 2022-09-03, For [#3167](https://github.com/ossrs/srs/issues/3167): WebRTC: Play stucked when republish. v4.0.260
* v4.0, 2022-09-02, For [#307](https://github.com/ossrs/srs/issues/307): WebRTC: Support use domain name as CANDIDATE. v4.0.259
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67 changes: 29 additions & 38 deletions trunk/src/app/srs_app_rtc_source.cpp
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Expand Up @@ -2914,40 +2914,35 @@ srs_error_t SrsRtcVideoRecvTrack::check_send_nacks()
return err;
}

SrsRtcJitter::SrsRtcJitter(uint32_t base)
SrsRtcTsJitter::SrsRtcTsJitter(uint32_t base)
{
pkt_base_ = pkt_last_ = 0;
correct_last_ = correct_base_ = 0;
base_ = base;
init_ = false;
int32_t threshold = 3 * 90 * 1000; // 3s in TBN=90K.
jitter_ = new SrsRtcJitter<uint32_t, int32_t>(base, threshold, srs_rtp_ts_distance);
}

SrsRtcJitter::~SrsRtcJitter()
SrsRtcTsJitter::~SrsRtcTsJitter()
{
srs_freep(jitter_);
}

uint32_t SrsRtcJitter::correct(uint32_t ts)
uint32_t SrsRtcTsJitter::correct(uint32_t value)
{
if (!init_) {
init_ = true;
correct_base_ = base_;
srs_trace("RTC: Jitter init base=%u, ts=%u", base_, ts);
}
if (!pkt_base_) pkt_base_ = ts;
return jitter_->correct(value);
}

if (pkt_last_) {
int32_t distance = srs_rtp_ts_distance(ts, pkt_last_);
static int32_t max_deviation = 90 * 3 * 1000;
if (distance > max_deviation || distance < -1 * max_deviation) {
srs_trace("RTC: Jitter rebase ts=%u, last=%u, distance=%d, pkt-base=%u/%u, correct-base=%u/%u", ts, pkt_last_, distance, pkt_base_, ts, correct_base_, correct_last_);
pkt_base_ = ts;
correct_base_ = correct_last_;
}
}
pkt_last_ = ts;
SrsRtcSeqJitter::SrsRtcSeqJitter(uint16_t base)
{
jitter_ = new SrsRtcJitter<uint16_t, int16_t>(base, 128, srs_rtp_seq_distance);
}

correct_last_ = correct_base_ + ts - pkt_base_;
return correct_last_;
SrsRtcSeqJitter::~SrsRtcSeqJitter()
{
srs_freep(jitter_);
}

uint16_t SrsRtcSeqJitter::correct(uint16_t value)
{
return jitter_->correct(value);
}

SrsRtcSendTrack::SrsRtcSendTrack(SrsRtcConnection* session, SrsRtcTrackDescription* track_desc, bool is_audio)
Expand All @@ -2956,10 +2951,9 @@ SrsRtcSendTrack::SrsRtcSendTrack(SrsRtcConnection* session, SrsRtcTrackDescripti
track_desc_ = track_desc->copy();
nack_no_copy_ = false;

seqno_ = 0;
init_ = false;
// Make a different start of sequence number, for debugging.
jitter_ = new SrsRtcJitter(track_desc_->type_ == "audio" ? 10000 : 20000);
jitter_ts_ = new SrsRtcTsJitter(track_desc_->type_ == "audio" ? 10000 : 20000);
jitter_seq_ = new SrsRtcSeqJitter(track_desc_->type_ == "audio" ? 100 : 200);

if (is_audio) {
rtp_queue_ = new SrsRtpRingBuffer(100);
Expand All @@ -2975,7 +2969,8 @@ SrsRtcSendTrack::~SrsRtcSendTrack()
srs_freep(rtp_queue_);
srs_freep(track_desc_);
srs_freep(nack_epp);
srs_freep(jitter_);
srs_freep(jitter_ts_);
srs_freep(jitter_seq_);
}

bool SrsRtcSendTrack::has_ssrc(uint32_t ssrc)
Expand Down Expand Up @@ -3029,18 +3024,14 @@ std::string SrsRtcSendTrack::get_track_id()
void SrsRtcSendTrack::rebuild_packet(SrsRtpPacket* pkt)
{
// Rebuild the sequence number.
if (!init_) {
init_ = true;
// Make a different start of sequence number, for debugging.
seqno_ = track_desc_->type_ == "audio" ? 1000 : 2000;
srs_trace("RTC: Seqno rebuild %s track=%s, ssrc=%d, seqno=%d to %d", track_desc_->type_.c_str(), track_desc_->id_.c_str(),
pkt->header.get_ssrc(), pkt->header.get_sequence(), seqno_);
}
pkt->header.set_sequence(seqno_++);
int16_t seq = pkt->header.get_sequence();
pkt->header.set_sequence(jitter_seq_->correct(seq));

// Rebuild the timestamp.
uint32_t ts = pkt->header.get_timestamp();
pkt->header.set_timestamp(jitter_->correct(ts));
pkt->header.set_timestamp(jitter_ts_->correct(ts));

srs_warn("RTC: Correct %s seq=%u/%u, ts=%u/%u", track_desc_->type_.c_str(), seq, pkt->header.get_sequence(), ts, pkt->header.get_timestamp());
}

srs_error_t SrsRtcSendTrack::on_nack(SrsRtpPacket** ppkt)
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90 changes: 74 additions & 16 deletions trunk/src/app/srs_app_rtc_source.hpp
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Expand Up @@ -594,24 +594,85 @@ class SrsRtcVideoRecvTrack : public SrsRtcRecvTrack, public ISrsRtspPacketDecode
virtual srs_error_t check_send_nacks();
};

// RTC jitter for TS or sequence number, only reset the base, and keep in original order.
template<typename T, typename ST>
class SrsRtcJitter
{
private:
// The ts about packet.
uint32_t pkt_base_;
uint32_t pkt_last_;
// The ts after corrected.
uint32_t correct_base_;
uint32_t correct_last_;
ST threshold_;
typedef ST (*PFN) (const T&, const T&);
PFN distance_;
private:
// The value about packet.
T pkt_base_;
T pkt_last_;
// The value after corrected.
T correct_base_;
T correct_last_;
// The base timestamp by config, start from it.
uint32_t base_;
T base_;
// Whether initialized. Note that we should not use correct_base_(0) as init state, because it might flip back.
bool init_;
public:
SrsRtcJitter(uint32_t base);
virtual ~SrsRtcJitter();
SrsRtcJitter(T base, ST threshold, PFN distance) {
threshold_ = threshold;
distance_ = distance;
base_ = base;

pkt_base_ = pkt_last_ = 0;
correct_last_ = correct_base_ = 0;
init_ = false;
}
virtual ~SrsRtcJitter() {
}
public:
uint32_t correct(uint32_t ts);
T correct(T value) {
if (!init_) {
init_ = true;
correct_base_ = base_;
pkt_base_ = value;
srs_trace("RTC: Jitter init base=%u, value=%u", base_, value);
}

if (true) {
ST distance = distance_(value, pkt_last_);
if (distance > threshold_ || distance < -1 * threshold_) {
srs_trace("RTC: Jitter rebase value=%u, last=%u, distance=%d, pkt-base=%u/%u, correct-base=%u/%u",
value, pkt_last_, distance, pkt_base_, value, correct_base_, correct_last_);
pkt_base_ = value;
correct_base_ = correct_last_;
}
}

pkt_last_ = value;
correct_last_ = correct_base_ + value - pkt_base_;

return correct_last_;
}
};

// For RTC timestamp jitter.
class SrsRtcTsJitter
{
private:
SrsRtcJitter<uint32_t, int32_t>* jitter_;
public:
SrsRtcTsJitter(uint32_t base);
virtual ~SrsRtcTsJitter();
public:
uint32_t correct(uint32_t value);
};

// For RTC sequence jitter.
class SrsRtcSeqJitter
{
private:
SrsRtcJitter<uint16_t, int16_t>* jitter_;
public:
SrsRtcSeqJitter(uint16_t base);
virtual ~SrsRtcSeqJitter();
public:
uint16_t correct(uint16_t value);
};

class SrsRtcSendTrack
Expand All @@ -625,12 +686,9 @@ class SrsRtcSendTrack
// NACK ARQ ring buffer.
SrsRtpRingBuffer* rtp_queue_;
protected:
// Current sequence number.
uint64_t seqno_;
// Whether initialized. Note that we should not use seqno_(0) as init state, because it might flip back.
bool init_;
// The jitter to correct ts.
SrsRtcJitter* jitter_;
// The jitter to correct ts and sequence number.
SrsRtcTsJitter* jitter_ts_;
SrsRtcSeqJitter* jitter_seq_;
private:
// By config, whether no copy.
bool nack_no_copy_;
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2 changes: 1 addition & 1 deletion trunk/src/core/srs_core_version4.hpp
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Expand Up @@ -9,6 +9,6 @@

#define VERSION_MAJOR 4
#define VERSION_MINOR 0
#define VERSION_REVISION 261
#define VERSION_REVISION 266

#endif
94 changes: 94 additions & 0 deletions trunk/src/utest/srs_utest_rtc.cpp
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Expand Up @@ -1275,3 +1275,97 @@ VOID TEST(KernelRTCTest, SyncTimestampBySenderReportDuplicated)
}
}

VOID TEST(KernelRTCTest, JitterTimestamp)
{
SrsRtcTsJitter jitter(1000);

// Starts from the base.
EXPECT_EQ(1000, jitter.correct(0));

// Start from here.
EXPECT_EQ(1010, jitter.correct(10));
EXPECT_EQ(1010, jitter.correct(10));
EXPECT_EQ(1020, jitter.correct(20));

// Reset the base for jitter detected.
EXPECT_EQ(1020, jitter.correct(20 + 90*3*1000 + 1));
EXPECT_EQ(1019, jitter.correct(20 + 90*3*1000));
EXPECT_EQ(1021, jitter.correct(20 + 90*3*1000 + 2));
EXPECT_EQ(1019, jitter.correct(20 + 90*3*1000));
EXPECT_EQ(1020, jitter.correct(20 + 90*3*1000 + 1));

// Rollback the timestamp.
EXPECT_EQ(1020, jitter.correct(20));
EXPECT_EQ(1021, jitter.correct(20 + 1));
EXPECT_EQ(1021, jitter.correct(21));

// Reset for jitter again.
EXPECT_EQ(1021, jitter.correct(21 + 90*3*1000 + 1));
EXPECT_EQ(1021, jitter.correct(21));

// No jitter at edge.
EXPECT_EQ(1021 + 90*3*1000, jitter.correct(21 + 90*3*1000));
EXPECT_EQ(1021 + 90*3*1000 + 1, jitter.correct(21 + 90*3*1000 + 1));
EXPECT_EQ(1021 + 1, jitter.correct(21 + 1));

// Also safety to decrease the value.
EXPECT_EQ(1021, jitter.correct(21));
EXPECT_EQ(1010, jitter.correct(10));

// Try to reset to 0 base.
EXPECT_EQ(1010, jitter.correct(10 + 90*3*1000 + 1010));
EXPECT_EQ(0, jitter.correct(10 + 90*3*1000));
EXPECT_EQ(0, jitter.correct(0));

// Also safety to start from zero.
EXPECT_EQ(10, jitter.correct(10));
EXPECT_EQ(11, jitter.correct(11));
}

VOID TEST(KernelRTCTest, JitterSequence)
{
SrsRtcSeqJitter jitter(100);

// Starts from the base.
EXPECT_EQ(100, jitter.correct(0));

// Normal without jitter.
EXPECT_EQ(101, jitter.correct(1));
EXPECT_EQ(102, jitter.correct(2));
EXPECT_EQ(101, jitter.correct(1));
EXPECT_EQ(103, jitter.correct(3));
EXPECT_EQ(110, jitter.correct(10));

// Reset the base for jitter detected.
EXPECT_EQ(110, jitter.correct(10 + 128 + 1));
EXPECT_EQ(109, jitter.correct(10 + 128));
EXPECT_EQ(110, jitter.correct(10 + 128 + 1));

// Rollback the timestamp.
EXPECT_EQ(110, jitter.correct(10));
EXPECT_EQ(111, jitter.correct(10 + 1));
EXPECT_EQ(111, jitter.correct(11));

// Reset for jitter again.
EXPECT_EQ(111, jitter.correct(11 + 128 + 1));
EXPECT_EQ(111, jitter.correct(11));

// No jitter at edge.
EXPECT_EQ(111 + 128, jitter.correct(11 + 128));
EXPECT_EQ(111 + 128 + 1, jitter.correct(11 + 128 + 1));
EXPECT_EQ(111 + 1, jitter.correct(11 + 1));

// Also safety to decrease the value.
EXPECT_EQ(111, jitter.correct(11));
EXPECT_EQ(110, jitter.correct(10));

// Try to reset to 0 base.
EXPECT_EQ(110, jitter.correct(10 + 128 + 110));
EXPECT_EQ(0, jitter.correct(10 + 128));
EXPECT_EQ(0, jitter.correct(0));

// Also safety to start from zero.
EXPECT_EQ(10, jitter.correct(10));
EXPECT_EQ(11, jitter.correct(11));
}

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