A note on the redundancy of reversible variable length codes

An improved upper bound on the redundancy of the optimal reversible variable length code (RVLC), is presented in terms of the largest symbol probability p
₁
. The improvement is achieved for 2/9 <; p
₁
<; 1/4 and for 2/5 ≤ p
₁
≤ 1/2. The bound guarantees that in these two regions, the redundancy of the optimal RVLC is less than 1 bit per symbol.