diff --git a/codec/h264/lex.go b/codec/h264/lex.go
index 81eca759..b9a58ad2 100644
--- a/codec/h264/lex.go
+++ b/codec/h264/lex.go
@@ -269,8 +269,7 @@ func (l *RTPLexer) handleFUA(d []byte) {
 		if end {
 			panic("bad fragmentation packet")
 		}
-		const FUIndicatorIdx = 0
-		newHead := (d[FUIndicatorIdx] & 0xe0) | (d[FUHeadIdx] & 0x1f)
+		newHead := (d[0] & 0xe0) | (d[0] & 0x1f)
 		d = d[1:]
 		d[0] = newHead
 		l.frag = true