From 647f10f212a6929c30dfae7f0ad7ca7cad2fa1d3 Mon Sep 17 00:00:00 2001
From: scruzin <anoble@gmail.com>
Date: Mon, 7 Jan 2019 08:44:04 +1030
Subject: [PATCH] Only set ts in C_RTMP_SendPacket() when prevPacket != nil.

---
 rtmp/rtmp.go | 26 +++++++++++++++-----------
 1 file changed, 15 insertions(+), 11 deletions(-)

diff --git a/rtmp/rtmp.go b/rtmp/rtmp.go
index b649d262..ef36a3f1 100644
--- a/rtmp/rtmp.go
+++ b/rtmp/rtmp.go
@@ -444,6 +444,7 @@ func C_ReadN(r *C_RTMP, buf []byte) error {
 // int WriteN(RTMP* r, const char* buffer, int n);
 // rtmp.c +1502
 func C_WriteN(r *C_RTMP, buf []byte) error {
+	//ToDo: consider using a different timeout for writes than for reads
 	err := r.Link.conn.SetWriteDeadline(time.Now().Add(time.Second * time.Duration(r.Link.timeout)))
 	if err != nil {
 		return err
@@ -1366,11 +1367,14 @@ func C_RTMP_SendPacket(r *C_RTMP, packet *C_RTMPPacket, queue int) error {
 		hSize += cSize
 	}
 
-	t := uint32(int(packet.m_nTimeStamp) - last)
-	if t >= 0xffffff {
+	var ts uint32
+	if prevPacket != nil {
+		ts = uint32(int(packet.m_nTimeStamp) - last)
+	}
+	if ts >= 0xffffff {
 		origIdx -= 4
 		hSize += 4
-		log.Printf("Larger timestamp than 24-bit: 0x%v", t)
+		log.Printf("Larger timestamp than 24-bit: 0x%v", ts)
 	}
 
 	headerIdx := origIdx
@@ -1399,8 +1403,8 @@ func C_RTMP_SendPacket(r *C_RTMP, packet *C_RTMPPacket, queue int) error {
 	}
 
 	if packetSize[packet.m_headerType] > 1 {
-		res := t
-		if t > 0xffffff {
+		res := ts
+		if ts > 0xffffff {
 			res = 0xffffff
 		}
 		C_AMF_EncodeInt24(headBytes[headerIdx:], int32(res))
@@ -1419,8 +1423,8 @@ func C_RTMP_SendPacket(r *C_RTMP, packet *C_RTMPPacket, queue int) error {
 		headerIdx += n
 	}
 
-	if t >= 0xffffff {
-		C_AMF_EncodeInt32(headBytes[headerIdx:], int32(t))
+	if ts >= 0xffffff {
+		C_AMF_EncodeInt32(headBytes[headerIdx:], int32(ts))
 		headerIdx += 4 // 32bits
 	}
 
@@ -1429,7 +1433,7 @@ func C_RTMP_SendPacket(r *C_RTMP, packet *C_RTMPPacket, queue int) error {
 
 	if debugMode {
 		if r.Link.conn != nil {
-			log.Printf("C_RTMP_SendPacket: %v=>%v, size=%v", r.Link.conn.LocalAddr(), r.Link.conn.RemoteAddr(), nSize)
+			log.Printf("C_RTMP_SendPacket: %v->%v, size=%v", r.Link.conn.LocalAddr(), r.Link.conn.RemoteAddr(), nSize)
 		}
 	}
 
@@ -1453,7 +1457,7 @@ func C_RTMP_SendPacket(r *C_RTMP, packet *C_RTMPPacket, queue int) error {
 			origIdx -= 1 + cSize
 			hSize = 1 + cSize
 
-			if t >= 0xffffff {
+			if ts >= 0xffffff {
 				origIdx -= 4
 				hSize += 4
 			}
@@ -1468,9 +1472,9 @@ func C_RTMP_SendPacket(r *C_RTMP, packet *C_RTMPPacket, queue int) error {
 					headBytes[origIdx+2] = byte(tmp >> 8)
 				}
 			}
-			if t >= 0xffffff {
+			if ts >= 0xffffff {
 				extendedTimestamp := headBytes[origIdx+1+cSize:]
-				C_AMF_EncodeInt32(extendedTimestamp[:4], int32(t))
+				C_AMF_EncodeInt32(extendedTimestamp[:4], int32(ts))
 			}
 		}
 	}