diff --git a/container/mts/mpegts_test.go b/container/mts/mpegts_test.go
index 3bd7bf59..eed1162a 100644
--- a/container/mts/mpegts_test.go
+++ b/container/mts/mpegts_test.go
@@ -33,7 +33,7 @@ func TestGetPTSRange(t *testing.T) {
 	var clip bytes.Buffer
 
 	// Write the PSI first.
-	err := writePSI(clip)
+	err := writePSI(&clip)
 	if err != nil {
 		t.Fatalf("did not expect error writing psi: %v", err)
 	}
@@ -43,7 +43,7 @@ func TestGetPTSRange(t *testing.T) {
 	for _, frame := range frames {
 		nextPTS := curTime * ptsFreq
 
-		err = writeFrame(clip, frame, uint64(nextPTS))
+		err = writeFrame(&clip, frame, uint64(nextPTS))
 		if err != nil {
 			t.Fatalf("did not expect error writing frame: %v", err)
 		}
@@ -63,7 +63,7 @@ func TestGetPTSRange(t *testing.T) {
 }
 
 // writePSI is a helper function write the PSI found at the start of a clip.
-func writePSI(b bytes.Buffer) error {
+func writePSI(b *bytes.Buffer) error {
 	// Write PAT.
 	pat := Packet{
 		PUSI:    true,
@@ -95,7 +95,7 @@ func writePSI(b bytes.Buffer) error {
 // writeFrame is a helper function used to form a PES packet from a frame, and
 // then fragment this across MPEGTS packets where they are then written to the
 // given buffer.
-func writeFrame(b bytes.Buffer, frame []byte, pts uint64) error {
+func writeFrame(b *bytes.Buffer, frame []byte, pts uint64) error {
 	// Prepare PES data.
 	pesPkt := pes.Packet{
 		StreamID:     videoStreamID,