diff --git a/container/mts/encoder.go b/container/mts/encoder.go
index a1598dd8..c47537bf 100644
--- a/container/mts/encoder.go
+++ b/container/mts/encoder.go
@@ -34,10 +34,10 @@ import (
 	"bitbucket.org/ausocean/av/container/mts/psi"
 )
 
-// Some common manifestations of PSI
+// Some common manifestations of PSI.
 var (
-	// standardPat is a minimal PAT.
-	standardPat = psi.PSI{
+	// StandardPAT is a minimal PAT.
+	StandardPAT = psi.PSI{
 		Pf:  0x00,
 		Tid: 0x00,
 		Ssi: true,
@@ -55,6 +55,30 @@ var (
 			},
 		},
 	}
+
+	// Standard PMT is a minimal PMT.
+	StandardPMT = psi.PSI{
+		Pf:  0x00,
+		Tid: 0x02,
+		Ssi: true,
+		Sl:  0x12,
+		Tss: &psi.TSS{
+			Tide: 0x01,
+			V:    0,
+			Cni:  true,
+			Sn:   0,
+			Lsn:  0,
+			Sd: &psi.PMT{
+				Pcrpid: 0x0100,
+				Pil:    0,
+				Essd: &psi.ESSD{
+					St:   H264ID,
+					Epid: 0x0100,
+					Esil: 0x00,
+				},
+			},
+		},
+	}
 )
 
 const (
@@ -69,7 +93,7 @@ const (
 var Meta *meta.Data
 
 var (
-	patTable = standardPat.Bytes()
+	patTable = StandardPAT.Bytes()
 	pmtTable []byte
 )
 
@@ -102,6 +126,9 @@ const (
 
 	// PTSFrequency is the presentation timestamp frequency in Hz.
 	PTSFrequency = 90000
+
+	// MaxPTS is the largest PTS value (i.e., for a 33-bit unsigned integer).
+	MaxPTS = (1 << 33) - 1
 )
 
 // Encoder encapsulates properties of an MPEG-TS generator.
@@ -143,29 +170,20 @@ func NewEncoder(dst io.WriteCloser, rate float64, mediaType int) *Encoder {
 		sid = H264ID
 	}
 
-	// standardPmt is a minimal PMT, without descriptors for metadata.
-	pmtTable = (&psi.PSI{
-		Pf:  0x00,
-		Tid: 0x02,
-		Ssi: true,
-		Sl:  0x12,
-		Tss: &psi.TSS{
-			Tide: 0x01,
-			V:    0,
-			Cni:  true,
-			Sn:   0,
-			Lsn:  0,
-			Sd: &psi.PMT{
-				Pcrpid: 0x0100,
-				Pil:    0,
-				Essd: &psi.ESSD{
-					St:   byte(sid),
-					Epid: 0x0100,
-					Esil: 0x00,
-				},
+	// StandardPmt is a minimal PMT, without descriptors for metadata.
+	pmt := StandardPMT
+	if sid != H264ID {
+		pmt.Tss.Sd = &psi.PMT{
+			Pcrpid: 0x0100,
+			Pil:    0,
+			Essd: &psi.ESSD{
+				St:   byte(sid),
+				Epid: 0x0100,
+				Esil: 0x00,
 			},
-		},
-	}).Bytes()
+		}
+	}
+	pmtTable = pmt.Bytes()
 
 	return &Encoder{
 		dst: dst,