diff --git a/container/mts/encoder.go b/container/mts/encoder.go
index 693b0be3..a903500b 100644
--- a/container/mts/encoder.go
+++ b/container/mts/encoder.go
@@ -136,19 +136,19 @@ type Encoder struct {
 	tsSpace     [PacketSize]byte
 	pesSpace    [pes.MaxPesSize]byte
 
-	continuity map[int]byte
+	continuity map[uint16]byte
 
 	nalBasedPSI  bool
 	pktCount     int
 	psiSendCount int
-	mediaPid     int
+	mediaPid     uint16
 	streamID     byte
 }
 
 // NewEncoder returns an Encoder with the specified media type and rate eg. if a video stream
 // calls write for every frame, the rate will be the frame rate of the video.
 func NewEncoder(dst io.WriteCloser, rate float64, mediaType int) *Encoder {
-	var mPid int
+	var mPid uint16
 	var sid byte
 	nbp := true
 	switch mediaType {
@@ -170,7 +170,7 @@ func NewEncoder(dst io.WriteCloser, rate float64, mediaType int) *Encoder {
 		Pil:    0,
 		Essd: &psi.ESSD{
 			St:   byte(sid),
-			Epid: uint16(mPid),
+			Epid: mPid,
 			Esil: 0x00,
 		},
 	}
@@ -189,7 +189,7 @@ func NewEncoder(dst io.WriteCloser, rate float64, mediaType int) *Encoder {
 		mediaPid: mPid,
 		streamID: sid,
 
-		continuity: map[int]byte{
+		continuity: map[uint16]byte{
 			PatPid: 0,
 			PmtPid: 0,
 			mPid:   0,
@@ -331,7 +331,7 @@ func (e *Encoder) pcr() uint64 {
 }
 
 // ccFor returns the next continuity counter for pid.
-func (e *Encoder) ccFor(pid int) byte {
+func (e *Encoder) ccFor(pid uint16) byte {
 	cc := e.continuity[pid]
 	const continuityCounterMask = 0xf
 	e.continuity[pid] = (cc + 1) & continuityCounterMask