diff --git a/rtmp/rtmp.go b/rtmp/rtmp.go
index 58cdf042..27a5b927 100644
--- a/rtmp/rtmp.go
+++ b/rtmp/rtmp.go
@@ -87,6 +87,8 @@ func AVC(str string) C.AVal {
 // av_setDataFrame is a static const global in rtmp.c
 var setDataFrame = AVC("@setDataFrame")
 
+var packetSize = [...]int32{ 12, 8, 4, 1}
+
 // Session provides an interface for sending flv tags over rtmp.
 type Session interface {
 	Open() error
@@ -263,21 +265,24 @@ func sendPacket(r *C.RTMP, packet *C.RTMPPacket, queue int) int {
 
 	if packet.m_nChannel >= r.m_channelsAllocatedOut {
 		n := int(packet.m_nChannel+10)
-		packets := C.realloc(r.m_vecChannelsOut, unsafe.Sizeof(*C.RTMPPacket) * n)
+		var tmp *C.RTMPPacket
+		packets := C.realloc(unsafe.Pointer(r.m_vecChannelsOut),
+			C.ulong(unsafe.Sizeof(tmp) * uintptr(n)))
 
-		if packets == 0 {
-			C.free(r.m_vecChannelsOut)
+		if uintptr(packets) == uintptr(0) {
+			C.free(unsafe.Pointer(r.m_vecChannelsOut))
 			r.m_vecChannelsOut = nil
 			r.m_channelsAllocatedOut = 0
 			return 0
 		}
-		r.m_vecChannelsOut = packets
-		C.memset(r.m_vecChannelsOut + r.m_channelsAllocatedOut, 0,
-			unsafe.Sizeof(*RTMPPacket) * (n-r.m_channelsAllocatedOut))
-		r.m_channelsAllocatedOut = n
+		r.m_vecChannelsOut = (**C.RTMPPacket)(packets)
+		C.memset(incPtr(unsafe.Pointer(r.m_vecChannelsOut), int(r.m_channelsAllocatedOut),
+			int(unsafe.Sizeof(tmp))), 0, C.ulong(unsafe.Sizeof(tmp) *
+			uintptr(n-int(r.m_channelsAllocatedOut))))
+		r.m_channelsAllocatedOut = C.int(n)
 	}
-	prevPackt = *(**C.RTMPPacket)(incPtr(unsafe.Pointer(r.m_vecChannelsOut),
-		packet.m_nChannel))
+	prevPacket = *(**C.RTMPPacket)(incPtr(unsafe.Pointer(r.m_vecChannelsOut),
+		int(packet.m_nChannel), int(unsafe.Sizeof(packet))))
 
 	if prevPacket != nil && packet.m_headerType != RTMP_PACKET_SIZE_LARGE {
 		// compress a bit by using the prev packet's attributes
@@ -290,11 +295,11 @@ func sendPacket(r *C.RTMP, packet *C.RTMPPacket, queue int) int {
 
 		if prevPacket.m_nTimeStamp == packet.m_nTimeStamp &&
 			packet.m_headerType == RTMP_PACKET_SIZE_SMALL {
-
-			packet.m_headerType = RTMP_PACKET_SIZE_MINIMUM
+			// TODO: port this constant
+			packet.m_headerType = C.RTMP_PACKET_SIZE_MINIMUM
 		}
 
-		last = prevPacket.m_nTimeStamp
+		last = int(prevPacket.m_nTimeStamp)
 	}
 
 	if packet.m_headerType > 3 {
@@ -303,13 +308,13 @@ func sendPacket(r *C.RTMP, packet *C.RTMPPacket, queue int) int {
 		return 0
 	}
 
-	nSize = int(*(*int)(incPtr(unsafe.Pointer(packetSize),int(packet.m_headerType))))
+	nSize = int(*(*int)(incInt32Ptr(unsafe.Pointer(&packetSize[0]),int(packet.m_headerType))))
 	hSize = nSize
 	cSize = 0
-	t = packet.m_nTimeStamp - last
+	t = int32(int(packet.m_nTimeStamp) - last)
 
-	if packet.m_body {
-		header = packet.m_body - nSize
+	if packet.m_body != nil {
+		header = decPtr(unsafe.Pointer(packet.m_body), nSize,
 		hend = packet.m_body
 	} else {
 		header = incPtr(hbuf,6)
@@ -572,20 +577,20 @@ func indxInt64Ptr(ptr unsafe.Pointer, inc int) int64 {
 	return *(*int64)(incPtr(ptr, inc, int64Size))
 }
 
-// incBytePtr returns an unsafe.Pointer to a byte that is inc positions
+// incBytePtr returns an unsafe.Pointer to a byte that is inc positive positions
 // from the passed ptr
 func incBytePtr(ptr unsafe.Pointer, inc int) unsafe.Pointer {
 	return incPtr(ptr,inc,byteSize)
 }
 
-// incInt32Ptr returns an unsafe.Pointer to an int32 that is inc positions from
-// the passed ptr
+// incInt32Ptr returns an unsafe.Pointer to an int32 that is inc positive
+// positions from the passed ptr
 func incInt32Ptr(ptr unsafe.Pointer, inc int) unsafe.Pointer {
 	return incPtr(ptr,inc,int32Size)
 }
 
-// incInt64Ptr returns an unsafe.Pointer to an int64 that is inc positions from
-// the passed ptr
+// incInt64Ptr returns an unsafe.Pointer to an int64 that is inc positive
+// positions from the passed ptr
 func incInt64Ptr(ptr unsafe.Pointer, inc int) unsafe.Pointer {
 	return incPtr(ptr,inc,int64Size)
 }
@@ -600,6 +605,24 @@ func decPtr(ptr unsafe.Pointer, dec, typeSize int) unsafe.Pointer {
 	return unsafe.Pointer(uintptr(ptr) - uintptr(dec*typeSize))
 }
 
+// decBytePtr returns an unsafe.Pointer to a byte that is dec negative positions
+// from ptr
+func decBytePtr(ptr unsafe.Pointer, dec int) unsafe.Pointer {
+	return decPtr(ptr,dec,byteSize)
+}
+
+// decBytePtr returns an unsafe.Pointer to a int32 that is dec negative positions
+// from ptr
+func decInt32Ptr(ptr unsafe.Pointer, dec int) unsafe.Pointer {
+	return decPtr(ptr,dec,int32Size)
+}
+
+// decBytePtr returns an unsafe.Pointer to a int64 that is dec negative positions
+// from ptr
+func decInt64Ptr(ptr unsafe.Pointer, dec int) unsafe.Pointer {
+	return decPTr(ptr,dec,int64Size)
+}
+
 // sliceToPtr get's the address of the first data element and returns as unsafe
 // pointer
 func sliceToPtr(data []byte) unsafe.Pointer {