diff --git a/container/mts/encoder.go b/container/mts/encoder.go
index 96cde642..83a7b403 100644
--- a/container/mts/encoder.go
+++ b/container/mts/encoder.go
@@ -303,12 +303,12 @@ func (e *Encoder) tick() {
 
 // pts retuns the current presentation timestamp.
 func (e *Encoder) pts() uint64 {
-	return uint64((e.clock + e.ptsOffset).Seconds() * pcrFreq)
+	return uint64((e.clock + e.ptsOffset).Seconds() * PTSFreq)
 }
 
 // pcr returns the current program clock reference.
 func (e *Encoder) pcr() uint64 {
-	return uint64(e.clock.Seconds() * pcrFreq)
+	return uint64(e.clock.Seconds() * PCRFreq)
 }
 
 // ccFor returns the next continuity counter for pid.