diff --git a/codec/h265/lex_test.go b/codec/h265/lex_test.go
index fac1dcc2..637a1860 100644
--- a/codec/h265/lex_test.go
+++ b/codec/h265/lex_test.go
@@ -45,7 +45,11 @@ func (r *rtpReader) Read(p []byte) (int, error) {
 	}
 	b := r.packets[r.idx]
 	n := copy(p, b)
-	r.idx++
+	if n < len(r.packets[r.idx]) {
+		r.packets[r.idx] = r.packets[r.idx][n:]
+	} else {
+		r.idx++
+	}
 	return n, nil
 }