From 5244e8b99809fd7afc75c901a07e00c252b4ed94 Mon Sep 17 00:00:00 2001
From: Mathis Engelbart <mathis.engelbart@gmail.com>
Date: Sun, 19 Jan 2025 17:17:48 +0100
Subject: [PATCH] Add report reception timestamps

---
 pkg/ccfb/ccfb_receiver.go |  6 +++---
 pkg/ccfb/history.go       |  7 ++++---
 pkg/ccfb/history_test.go  |  2 +-
 pkg/ccfb/interceptor.go   | 10 ++++++----
 pkg/ccfb/twcc_receiver.go |  7 ++++---
 5 files changed, 18 insertions(+), 14 deletions(-)

diff --git a/pkg/ccfb/ccfb_receiver.go b/pkg/ccfb/ccfb_receiver.go
index 811c636d..a90a9e9b 100644
--- a/pkg/ccfb/ccfb_receiver.go
+++ b/pkg/ccfb/ccfb_receiver.go
@@ -19,16 +19,16 @@ type acknowledgementList struct {
 	acks []acknowledgement
 }
 
-func convertCCFB(ts time.Time, feedback *rtcp.CCFeedbackReport) map[uint32]acknowledgementList {
+func convertCCFB(ts time.Time, feedback *rtcp.CCFeedbackReport) (time.Time, map[uint32]acknowledgementList) {
 	if feedback == nil {
-		return nil
+		return time.Time{}, nil
 	}
 	result := map[uint32]acknowledgementList{}
 	referenceTime := ntp.ToTime32(feedback.ReportTimestamp, ts)
 	for _, rb := range feedback.ReportBlocks {
 		result[rb.MediaSSRC] = convertMetricBlock(ts, referenceTime, rb.BeginSequence, rb.MetricBlocks)
 	}
-	return result
+	return referenceTime, result
 }
 
 func convertMetricBlock(ts time.Time, reference time.Time, seqNrOffset uint16, blocks []rtcp.CCFeedbackMetricBlock) acknowledgementList {
diff --git a/pkg/ccfb/history.go b/pkg/ccfb/history.go
index bec0f769..6e8aba3c 100644
--- a/pkg/ccfb/history.go
+++ b/pkg/ccfb/history.go
@@ -11,7 +11,8 @@ import (
 )
 
 type PacketReportList struct {
-	Timestamp time.Time
+	Arrival   time.Time
+	Departure time.Time
 	Reports   []PacketReport
 }
 
@@ -109,7 +110,7 @@ func (h *history) getReportForAck(al acknowledgementList) PacketReportList {
 	}
 
 	return PacketReportList{
-		Timestamp: al.ts,
-		Reports:   reports,
+		Arrival: al.ts,
+		Reports: reports,
 	}
 }
diff --git a/pkg/ccfb/history_test.go b/pkg/ccfb/history_test.go
index 4a56fd11..88ca99e4 100644
--- a/pkg/ccfb/history_test.go
+++ b/pkg/ccfb/history_test.go
@@ -72,7 +72,7 @@ func TestHistory(t *testing.T) {
 					},
 				},
 				expectedReport: PacketReportList{
-					Timestamp: time.Time{}.Add(time.Second),
+					Arrival: time.Time{}.Add(time.Second),
 					Reports: []PacketReport{
 						{1, 1200, time.Time{}.Add(2 * time.Millisecond), true, time.Time{}.Add(3 * time.Millisecond), 0},
 						{2, 1200, time.Time{}.Add(3 * time.Millisecond), false, time.Time{}, 0},
diff --git a/pkg/ccfb/interceptor.go b/pkg/ccfb/interceptor.go
index e8b4afef..08de7429 100644
--- a/pkg/ccfb/interceptor.go
+++ b/pkg/ccfb/interceptor.go
@@ -93,12 +93,12 @@ func (i *Interceptor) BindLocalStream(info *interceptor.StreamInfo, writer inter
 // BindRTCPReader implements interceptor.Interceptor.
 func (i *Interceptor) BindRTCPReader(reader interceptor.RTCPReader) interceptor.RTCPReader {
 	return interceptor.RTCPReaderFunc(func(b []byte, a interceptor.Attributes) (int, interceptor.Attributes, error) {
-		now := i.timestamp()
-
 		n, attr, err := reader.Read(b, a)
 		if err != nil {
 			return n, attr, err
 		}
+		now := i.timestamp()
+
 		buf := make([]byte, n)
 		copy(buf, b[:n])
 
@@ -111,14 +111,16 @@ func (i *Interceptor) BindRTCPReader(reader interceptor.RTCPReader) interceptor.
 		pkts, err := attr.GetRTCPPackets(buf)
 		for _, pkt := range pkts {
 			var reportLists map[uint32]acknowledgementList
+			var reportDeparture time.Time
 			switch fb := pkt.(type) {
 			case *rtcp.CCFeedbackReport:
-				reportLists = convertCCFB(now, fb)
+				reportDeparture, reportLists = convertCCFB(now, fb)
 			case *rtcp.TransportLayerCC:
-				reportLists = convertTWCC(now, fb)
+				reportDeparture, reportLists = convertTWCC(now, fb)
 			}
 			for ssrc, reportList := range reportLists {
 				prl := i.ssrcToHistory[ssrc].getReportForAck(reportList)
+				prl.Departure = reportDeparture
 				if l, ok := pktReportLists[ssrc]; !ok {
 					pktReportLists[ssrc] = &prl
 				} else {
diff --git a/pkg/ccfb/twcc_receiver.go b/pkg/ccfb/twcc_receiver.go
index d5c4c195..c7783e86 100644
--- a/pkg/ccfb/twcc_receiver.go
+++ b/pkg/ccfb/twcc_receiver.go
@@ -7,14 +7,15 @@ import (
 	"github.com/pion/rtcp"
 )
 
-func convertTWCC(ts time.Time, feedback *rtcp.TransportLayerCC) map[uint32]acknowledgementList {
+func convertTWCC(ts time.Time, feedback *rtcp.TransportLayerCC) (time.Time, map[uint32]acknowledgementList) {
 	log.Printf("got twcc report: %v", feedback)
 	if feedback == nil {
-		return nil
+		return time.Time{}, nil
 	}
 	var acks []acknowledgement
 
 	nextTimestamp := time.Time{}.Add(time.Duration(feedback.ReferenceTime) * 64 * time.Millisecond)
+	reportDeparture := nextTimestamp
 	recvDeltaIndex := 0
 
 	offset := 0
@@ -85,7 +86,7 @@ func convertTWCC(ts time.Time, feedback *rtcp.TransportLayerCC) map[uint32]ackno
 		}
 	}
 
-	return map[uint32]acknowledgementList{
+	return reportDeparture, map[uint32]acknowledgementList{
 		0: {
 			ts:   ts,
 			acks: acks,