Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

[core] Fixed getTsbPdTimeBase: carryover within 2 wrapping periods #2043

Merged
merged 2 commits into from
Jun 21, 2021
Merged

[core] Fixed getTsbPdTimeBase: carryover within 2 wrapping periods #2043

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
c351387
[core] Fixed getTsbPdTimeBase: carryover within 2 wrapping periods
maxsharabayko Jun 18, 2021
13ddaaf
Replaced auto type
maxsharabayko Jun 21, 2021
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
28 changes: 19 additions & 9 deletions srtcore/tsbpd_time.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -38,6 +38,7 @@ class drift_logger
int64_t drift_sample,
int64_t drift,
int64_t overdrift,
const srt::sync::steady_clock::time_point& pkt_base,
const srt::sync::steady_clock::time_point& tsbpd_base)
{
using namespace srt::sync;
Expand All @@ -50,13 +51,17 @@ class drift_logger
std::string str_tbase = srt::sync::FormatTime(tsbpd_base);
str_tbase.resize(str_tbase.size() - 7); // remove trailing ' [STDY]' part

std::string str_pkt_base = srt::sync::FormatTime(pkt_base);
str_pkt_base.resize(str_pkt_base.size() - 7); // remove trailing ' [STDY]' part

// m_fout << str_tnow << ",";
m_fout << count_microseconds(steady_clock::now() - m_start_time) << ",";
m_fout << ackack_timestamp << ",";
m_fout << rtt_us << ",";
m_fout << drift_sample << ",";
m_fout << drift << ",";
m_fout << overdrift << ",";
m_fout << str_pkt_base << ",";
m_fout << str_tbase << "\n";
m_fout.flush();
}
Expand All @@ -65,7 +70,7 @@ class drift_logger
void print_header()
{
m_fout << "usElapsedStd,usAckAckTimestampStd,";
m_fout << "usRTTStd,usDriftSampleStd,usDriftStd,usOverdriftStd,TSBPDBase\n";
m_fout << "usRTTStd,usDriftSampleStd,usDriftStd,usOverdriftStd,tsPktBase,TSBPDBase\n";
}

void create_file()
Expand Down Expand Up @@ -121,8 +126,9 @@ bool CTsbpdTime::addDriftSample(uint32_t usPktTimestamp,
// A change in network delay has to be taken into account. The only way to get some estimation of it
// is to estimate RTT change and assume that the change of the one way network delay is
// approximated by the half of the RTT change.
const duration tdRTTDelta = microseconds_from((usRTTSample - m_iFirstRTT) / 2);
const steady_clock::duration tdDrift = tsNow - getPktTsbPdBaseTime(usPktTimestamp) - tdRTTDelta;
const duration tdRTTDelta = microseconds_from((usRTTSample - m_iFirstRTT) / 2);
const time_point tsPktBaseTime = getPktTsbPdBaseTime(usPktTimestamp);
const steady_clock::duration tdDrift = tsNow - tsPktBaseTime - tdRTTDelta;

const bool updated = m_DriftTracer.update(count_microseconds(tdDrift));

Expand Down Expand Up @@ -152,6 +158,7 @@ bool CTsbpdTime::addDriftSample(uint32_t usPktTimestamp,
count_microseconds(tdDrift),
m_DriftTracer.drift(),
m_DriftTracer.overdrift(),
tsPktBaseTime,
m_tsTsbPdTimeBase);
#endif
return updated;
Expand All @@ -168,7 +175,7 @@ void CTsbpdTime::setTsbPdMode(const steady_clock::time_point& timebase, bool wra
//
// This function is called in the HSREQ reception handler only.
m_tsTsbPdTimeBase = timebase;
m_tdTsbPdDelay = delay;
m_tdTsbPdDelay = delay;
}

void CTsbpdTime::applyGroupTime(const steady_clock::time_point& timebase,
Expand Down Expand Up @@ -210,8 +217,11 @@ void CTsbpdTime::applyGroupDrift(const steady_clock::time_point& timebase,

CTsbpdTime::time_point CTsbpdTime::getTsbPdTimeBase(uint32_t timestamp_us) const
{
const uint64_t carryover_us =
(m_bTsbPdWrapCheck && timestamp_us < TSBPD_WRAP_PERIOD) ? uint64_t(CPacket::MAX_TIMESTAMP) + 1 : 0;
// A data packet within [TSBPD_WRAP_PERIOD; 2 * TSBPD_WRAP_PERIOD] would end TSBPD wrap-aware state.
// Some incoming control packets may not update the TSBPD base (calling updateTsbPdTimeBase(..)),
// but may come before a data packet with a timestamp in this range. Therefore the whole range should be tracked.
const int64_t carryover_us =
(m_bTsbPdWrapCheck && timestamp_us <= 2 * TSBPD_WRAP_PERIOD) ? int64_t(CPacket::MAX_TIMESTAMP) + 1 : 0;

return (m_tsTsbPdTimeBase + microseconds_from(carryover_us));
}
Expand Down Expand Up @@ -243,14 +253,14 @@ void CTsbpdTime::updateTsbPdTimeBase(uint32_t usPktTimestamp)
return;
}

// Check if timestamp is in the last 30 seconds before reaching the MAX_TIMESTAMP.
// Check if timestamp is within the TSBPD_WRAP_PERIOD before reaching the MAX_TIMESTAMP.
if (usPktTimestamp > (CPacket::MAX_TIMESTAMP - TSBPD_WRAP_PERIOD))
{
// Approching wrap around point, start wrap check period (if for packet delivery head)
m_bTsbPdWrapCheck = true;
LOGC(tslog.Debug,
log << "tsbpd wrap period begins with ts=" << usPktTimestamp << " drift: " << m_DriftTracer.drift()
<< "us.");
log << "tsbpd wrap period begins with ts=" << usPktTimestamp
<< " TIME BASE: " << FormatTime(m_tsTsbPdTimeBase) << " drift: " << m_DriftTracer.drift() << "us.");
}
}

Expand Down