diff --git a/container/mts/mpegts.go b/container/mts/mpegts.go
index ef2e6306..5f326942 100644
--- a/container/mts/mpegts.go
+++ b/container/mts/mpegts.go
@@ -341,7 +341,7 @@ func GetPTSRange(clip []byte) (pts [2]uint64, err error) {
 	}
 	pts[0] = _pes.PTS()
 
-	// Get the final PTS and calculate PTS immediately after.
+	// Get the final PTS searching from end of clip for access unit start.
 	for i := len(clip) - PacketSize; i >= 0; i -= PacketSize {
 		copy(_pkt[:], clip[i:i+PacketSize])
 		if packet.PayloadUnitStartIndicator(&_pkt) {