diff --git a/stream/rtp/rtp.go b/stream/rtp/rtp.go
index 1ee1422f..164f9951 100644
--- a/stream/rtp/rtp.go
+++ b/stream/rtp/rtp.go
@@ -36,17 +36,17 @@ const (
 )
 
 type Pkt struct {
-	V       byte
-	P       byte
-	X       byte
-	CC      byte
-	M       byte
-	PT      byte
-	SN      int16
-	TS      int32
-	SSRC    int32
-	Payload []byte
-	Padding int
+	V       byte   // Version (currently 2)
+	P       byte   // Padding indicator (0 => padding, 1 => padding)
+	X       byte   // Extension header indicator
+	CC      byte   // CSRC count
+	M       byte   // Marker bit
+	PT      byte   // Packet type
+	SN      int16  // Synch number
+	TS      int32  // Timestamp
+	SSRC    int32  // Synchronisation source identifier
+	Payload []byte // H264 Payload data
+	Padding int    // No of bytes of padding
 }
 
 func (p *Pkt) Bytes() []byte {
@@ -64,6 +64,14 @@ func (p *Pkt) Bytes() []byte {
 		panic("CC has been set to something other than 0 - this is not supported yet!")
 	}
 
+	if p.X != 0 {
+		panic("rtp: X (extension header indicator) not 0, but extensiion headers not currently supported!")
+	}
+
+	if p.CC != 0 {
+		panic("rtp: CC (CSRC count) not 0, but CSRC headers not yet supported!")
+	}
+
 	buf := make([]byte, defaultHeadSize, defaultHeadSize+len(p.Payload)+p.Padding)
 	// First 4 bytes
 	buf[0] |= p.V<<6 | p.P<<5 | p.CC
diff --git a/stream/rtp/rtp_test.go b/stream/rtp/rtp_test.go
index 04213c75..aa84d92f 100644
--- a/stream/rtp/rtp_test.go
+++ b/stream/rtp/rtp_test.go
@@ -27,17 +27,44 @@ LICENSE
 
 package rtp
 
+import (
+	"reflect"
+	"testing"
+)
+
 var rtpTests = []struct {
-	pkt        Pkt
-	byteOutput []byte
+	num  int
+	pkt  Pkt
+	want []byte
 }{
 	{
-		pkt: Pkt{},
-	},
-	{
-		name:  "null short",
-		input: []byte{0x00, 0x00, 0x01, 0x0},
-		delay: 0,
-		want:  [][]byte{{0x0, 0x0, 0x1, 0x9, 0xf0, 0x00, 0x00, 0x01, 0x0}},
+		num: 1,
+		pkt: Pkt{
+			V:       2,
+			P:       0,
+			X:       0,
+			CC:      0,
+			M:       0,
+			PT:      6,
+			SN:      167,
+			TS:      160,
+			SSRC:    10,
+			Payload: []byte{0x00, 0x01, 0x07, 0xf0, 0x56, 0x37, 0x0a, 0x0f},
+			Padding: 0,
+		},
+		want: []byte{
+			0x80, 0x06, 0x00, 0xa7,
+			0x00, 0x00, 0x00, 0xa0,
+			0x00, 0x00, 0x00, 0x0a,
+			0x00, 0x01, 0x07, 0xf0,
+			0x56, 0x37, 0x0a, 0x0f,
+		},
 	},
 }
+
+func TestRtpPktToByteSlice(t *testing.T) {
+	got := rtpTests.pkt
+	if !reflect.DeepEqual(got, tests.Want) {
+		t.Errorf("unexpected error for %q: got:%v want:%v", test.num, got, tests.Want)
+	}
+}