From ed4b056c087c007ccb76eab109a41a88f9e0c8c5 Mon Sep 17 00:00:00 2001
From: Dave Taddei <davidtaddei@users.noreply.github.com>
Date: Mon, 19 Sep 2022 10:47:13 +0100
Subject: [PATCH] feat: Added RTSP receiver reports

---
 format/rtspv2/client.go | 49 +++++++++++++++++++++++++----------------
 1 file changed, 30 insertions(+), 19 deletions(-)

diff --git a/format/rtspv2/client.go b/format/rtspv2/client.go
index fb45e1a..dd57351 100644
--- a/format/rtspv2/client.go
+++ b/format/rtspv2/client.go
@@ -106,6 +106,11 @@ type RTSPClientOptions struct {
 	InsecureSkipVerify bool
 }
 
+type RTPMetadata struct {
+	SSRC      uint32
+	SeqNumber int
+}
+
 func Dial(options RTSPClientOptions) (*RTSPClient, error) {
 	client := &RTSPClient{
 		headers:             make(map[string]string),
@@ -261,8 +266,8 @@ func (client *RTSPClient) startStream() {
 	header := make([]byte, 4)
 	first := make([]byte, 2)
 	failed := 0
-	var ssrc uint32
-	ssrc = 0
+	var metaData RTPMetadata
+	metaData.SSRC = 0
 	for {
 		err := client.conn.SetDeadline(time.Now().Add(client.options.ReadWriteTimeout))
 		if err != nil {
@@ -276,8 +281,8 @@ func (client *RTSPClient) startStream() {
 				return
 			}
 
-			if ssrc != 0 {
-				client.sendRR(ssrc)
+			if metaData.SSRC != 0 {
+				client.sendRR(metaData)
 			}
 			timer = time.Now()
 		}
@@ -329,8 +334,8 @@ func (client *RTSPClient) startStream() {
 					return
 				}
 			}
-			pkt, got, _ssrc := client.RTPDemuxer(&content)
-			ssrc = _ssrc
+			pkt, got, _metaData := client.RTPDemuxer(&content)
+			metaData = _metaData
 			if !got {
 				continue
 			}
@@ -373,7 +378,8 @@ func (client *RTSPClient) startStream() {
 			failed = failed + 1
 			client.Println("RTSP Client RTP Read DeSync: Failed frames", failed)
 
-			ssrc = 0
+			metaData.SSRC = 0
+			metaData.SeqNumber = 0
 
 			if failed > 500 {
 				return
@@ -382,8 +388,8 @@ func (client *RTSPClient) startStream() {
 	}
 }
 
-func (client *RTSPClient) sendRR(ssrc uint32) (err error) {
-	client.Println("Sending ReceiverReport", ssrc)
+func (client *RTSPClient) sendRR(metaData RTPMetadata) (err error) {
+	client.Println("Sending ReceiverReport", metaData)
 	err = client.conn.SetDeadline(time.Now().Add(client.options.ReadWriteTimeout))
 	if err != nil {
 		return
@@ -393,12 +399,12 @@ func (client *RTSPClient) sendRR(ssrc uint32) (err error) {
 	rr := rtcp.ReceiverReport{}
 	recepReport := rtcp.ReceptionReport{}
 
-	rr.SSRC = ssrc
+	rr.SSRC = metaData.SSRC
 
-	recepReport.SSRC = ssrc
+	recepReport.SSRC = metaData.SSRC
 	recepReport.FractionLost = 0
 	recepReport.TotalLost = 0
-	recepReport.LastSequenceNumber = 0
+	recepReport.LastSequenceNumber = uint32(metaData.SeqNumber)
 	recepReport.Jitter = 0
 	recepReport.LastSenderReport = 0
 	recepReport.Delay = 0
@@ -618,7 +624,7 @@ func stringInBetween(str string, start string, end string) (result string) {
 	return str
 }
 
-func (client *RTSPClient) RTPDemuxer(payloadRAW *[]byte) ([]*av.Packet, bool, uint32) {
+func (client *RTSPClient) RTPDemuxer(payloadRAW *[]byte) ([]*av.Packet, bool, RTPMetadata) {
 	content := *payloadRAW
 	firstByte := content[4]
 	padding := (firstByte>>5)&1 == 1
@@ -628,6 +634,11 @@ func (client *RTSPClient) RTPDemuxer(payloadRAW *[]byte) ([]*av.Packet, bool, ui
 	timestamp := int64(binary.BigEndian.Uint32(content[8:12]))
 	ssrc := uint32(binary.BigEndian.Uint32(content[12:16]))
 
+	var metaData RTPMetadata
+
+	metaData.SSRC = ssrc
+	metaData.SeqNumber = SequenceNumber
+
 	if isRTCPPacket(content) {
 		client.Println("Processing RTCP packet")
 		rtcpPacketType := content[5]
@@ -639,7 +650,7 @@ func (client *RTSPClient) RTPDemuxer(payloadRAW *[]byte) ([]*av.Packet, bool, ui
 		} else {
 			client.Println("skipping RTCP packet")
 		}
-		return nil, false, 0
+		return nil, false, metaData
 	}
 
 	offset := RTPHeaderSize
@@ -649,7 +660,7 @@ func (client *RTSPClient) RTPDemuxer(payloadRAW *[]byte) ([]*av.Packet, bool, ui
 		offset += 4 * CSRCCnt
 	}
 	if extension && len(content) < 4+offset+2+2 {
-		return nil, false, 0
+		return nil, false, metaData
 	}
 	if extension && end-offset >= 4 {
 		extLen := 4 * int(binary.BigEndian.Uint16(content[4+offset+2:]))
@@ -689,7 +700,7 @@ func (client *RTSPClient) RTPDemuxer(payloadRAW *[]byte) ([]*av.Packet, bool, ui
 		}
 		nalRaw, _ := h264parser.SplitNALUs(content[offset:end])
 		if len(nalRaw) == 0 || len(nalRaw[0]) == 0 {
-			return nil, false, 0
+			return nil, false, metaData
 		}
 		var retmap []*av.Packet
 		for _, nal := range nalRaw {
@@ -829,7 +840,7 @@ func (client *RTSPClient) RTPDemuxer(payloadRAW *[]byte) ([]*av.Packet, bool, ui
 		}
 		if len(retmap) > 0 {
 			client.PreVideoTS = timestamp
-			return retmap, true, ssrc
+			return retmap, true, metaData
 		}
 	case client.audioID:
 		if client.PreAudioTS == 0 {
@@ -903,12 +914,12 @@ func (client *RTSPClient) RTPDemuxer(payloadRAW *[]byte) ([]*av.Packet, bool, ui
 		}
 		if len(retmap) > 0 {
 			client.PreAudioTS = timestamp
-			return retmap, true, ssrc
+			return retmap, true, metaData
 		}
 	default:
 		//client.Println("Unsuported Intervaled data packet", int(content[1]), content[offset:end])
 	}
-	return nil, false, ssrc
+	return nil, false, metaData
 }
 
 func (client *RTSPClient) CodecUpdateSPS(val []byte) {