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Log skew in clock rate. (#2158)

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* Log skew in clock rate.

Remember seeing sender report time stamp moving backward
across mute with replaceTrack(null). Not able to reproduce
it in JS sample app, but have seen it elsewhere.

Logging to understand it better. Wondering if the sender report
should be reset on time stamp moving backward or if we should drop
backwards moving reports.

* set threshold at 20%
This commit is contained in:
Raja Subramanian
2023-10-19 13:58:50 +05:30
committed by GitHub
parent 8d0bb526f7
commit e461e9cd79
2 changed files with 37 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
pkg/sfu/buffer/rtpstats_base.go
View File

@@ -105,6 +105,8 @@ type snapshot struct {
maxJitter float64
}
// ------------------------------------------------------------------
type RTCPSenderReportData struct {
RTPTimestamp uint32
RTPTimestampExt uint64
@@ -112,6 +114,16 @@ type RTCPSenderReportData struct {
At time.Time
}
func (r *RTCPSenderReportData) ToString() string {
if r == nil {
return ""
}
return fmt.Sprintf("ntp: %s, rtp: %d, extRtp: %d, at: %s", r.NTPTimestamp.Time().String(), r.RTPTimestamp, r.RTPTimestampExt, r.At.String())
}
// ------------------------------------------------------------------
type RTPStatsParams struct {
ClockRate uint32
Logger logger.Logger

39
pkg/sfu/buffer/rtpstats_receiver.go
View File

@@ -16,6 +16,7 @@ package buffer
import (
"fmt"
"math"
"time"
"github.com/pion/rtcp"
@@ -287,12 +288,8 @@ func (r *RTPStatsReceiver) SetRtcpSenderReportData(srData *RTCPSenderReportData)
if r.srNewest != nil && r.srNewest.NTPTimestamp > srData.NTPTimestamp {
r.logger.Infow(
"received anachronous sender report",
"currentNTP", srData.NTPTimestamp.Time().String(),
"currentRTP", srData.RTPTimestamp,
"currentAt", srData.At.String(),
"lastNTP", r.srNewest.NTPTimestamp.Time().String(),
"lastRTP", r.srNewest.RTPTimestamp,
"lastAt", r.srNewest.At.String(),
"last", r.srNewest.ToString(),
"current", srData.ToString(),
)
return
}
@@ -310,6 +307,26 @@ func (r *RTPStatsReceiver) SetRtcpSenderReportData(srData *RTCPSenderReportData)
r.maybeAdjustFirstPacketTime(srDataCopy.RTPTimestamp, r.timestamp.GetStart())
if r.srNewest != nil {
timeSinceLast := srData.NTPTimestamp.Time().Sub(r.srNewest.NTPTimestamp.Time()).Seconds()
rtpDiffSinceLast := srDataCopy.RTPTimestampExt - r.srNewest.RTPTimestampExt
calculatedClockRateFromLast := float64(rtpDiffSinceLast) / timeSinceLast
timeSinceFirst := srData.NTPTimestamp.Time().Sub(r.srFirst.NTPTimestamp.Time()).Seconds()
rtpDiffSinceFirst := srDataCopy.RTPTimestampExt - r.srFirst.RTPTimestampExt
calculatedClockRateFromFirst := float64(rtpDiffSinceFirst) / timeSinceFirst
if math.Abs(float64(r.params.ClockRate)-calculatedClockRateFromLast) > 0.2*float64(r.params.ClockRate) || math.Abs(float64(r.params.ClockRate)-calculatedClockRateFromFirst) > 0.2*float64(r.params.ClockRate) {
r.logger.Infow(
"clock rate skew",
"first", r.srFirst.ToString(),
"last", r.srNewest.ToString(),
"current", srDataCopy.ToString(),
"calculatedFirst", calculatedClockRateFromFirst,
"calculatedLast", calculatedClockRateFromLast,
)
}
}
if r.srNewest != nil && srDataCopy.RTPTimestampExt < r.srNewest.RTPTimestampExt {
// This can happen when a track is replaced with a null and then restored -
// i. e. muting replacing with null and unmute restoring the original track.
@@ -317,14 +334,8 @@ func (r *RTPStatsReceiver) SetRtcpSenderReportData(srData *RTCPSenderReportData)
// Resetting will ensure sample rate calculations do not go haywire due to negative time.
r.logger.Infow(
"received sender report, out-of-order, resetting",
"prevTSExt", r.srNewest.RTPTimestampExt,
"prevRTP", r.srNewest.RTPTimestamp,
"prevNTP", r.srNewest.NTPTimestamp.Time().String(),
"prevAt", r.srNewest.At.String(),
"currTSExt", srDataCopy.RTPTimestampExt,
"currRTP", srDataCopy.RTPTimestamp,
"currNTP", srDataCopy.NTPTimestamp.Time().String(),
"currentAt", srDataCopy.At.String(),
"last", r.srNewest.ToString(),
"current", srDataCopy.ToString(),
)
r.srFirst = nil
}