update logging on synchronizer reset

pkg/synchronizer/track.go

@@ -181,8 +181,7 @@ func (t *TrackSynchronizer) adjust(pkt *rtp.Packet) (int64, time.Duration, bool)
 		pkt.SequenceNumber = t.lastSN + 1
 
 		// reset RTP timestamps
-		logger.Debugw("resetting track synchronizer", "reason", "SN gap", "lastSN", t.lastSN, "SN", pkt.SequenceNumber)
-		ts, pts := t.resetRTP(pkt)
+		ts, pts := t.resetRTP(pkt, []any{"reason", "SN gap"})
 		return ts, pts, false
 	}
 
@@ -201,8 +200,11 @@ func (t *TrackSynchronizer) adjust(pkt *rtp.Packet) (int64, time.Duration, bool)
 	pts := t.getElapsed(ts) + t.ptsOffset
 	if expected := time.Since(t.startedAt.Add(t.ptsOffset)); pts > expected+maxTSDiff {
 		// reset RTP timestamps
-		logger.Debugw("resetting track synchronizer", "reason", "pts out of bounds", "pts", pts, "expected", expected)
-		ts, pts = t.resetRTP(pkt)
+		ts, pts = t.resetRTP(pkt, []any{
+			"reason", "pts out of bounds",
+			"pts", pts,
+			"expectedPTS", expected,
+		})
 		return ts, pts, false
 	}
 
@@ -213,12 +215,28 @@ func (t *TrackSynchronizer) getElapsed(ts int64) time.Duration {
 	return t.rtpConverter.toDuration(ts - t.firstTS)
 }
 
-func (t *TrackSynchronizer) resetRTP(pkt *rtp.Packet) (int64, time.Duration) {
-	frames := int64(time.Since(t.lastPacket) / t.getFrameDuration())
-	duration := t.getFrameDurationRTP() * frames
-	ts := t.lastTS + duration
-	pts := t.lastPTS + t.rtpConverter.toDuration(duration)
-	t.firstTS += int64(pkt.Timestamp) - ts
+func (t *TrackSynchronizer) resetRTP(pkt *rtp.Packet, fields []any) (int64, time.Duration) {
+	frameDuration := t.getFrameDuration()                     // avg frame duration
+	frames := int64(time.Since(t.lastPacket) / frameDuration) // number of frames we expect since the last packet
+	duration := t.getFrameDurationRTP() * frames              // expected increase in RTP time
+	ts := t.lastTS + duration                                 // expected new RTP time
+	pts := t.lastPTS + t.rtpConverter.toDuration(duration)    // expected new PTS
+
+	t.firstTS += int64(pkt.Timestamp) - ts // reset firstTS to align with new ts
+
+	fields = append(fields,
+		"pktTS", pkt.Timestamp,
+		"pktSN", pkt.SequenceNumber,
+		"prevTS", t.lastTS,
+		"prevSN", t.lastSN,
+		"frameDuration", frameDuration,
+		"prevPTS", t.lastPTS,
+		"adjustedTS", ts,
+		"adjustedPTS", pts,
+	)
+
+	logger.Debugw("resetting track synchronizer", fields...)
+
 	return ts, pts
 }