REVERSIBLE VARIABLE-LENGTH CODES

In this paper, we propose some reversible variable length codes (RVLC's) which can be decoded instantaneously both in the forward and backward directions and have high transmission efficiency. These codes can be used, for example, in the backward reconstruction of video signals from the data last received when some signal is lost midway in the transmission. Schemes for a symmetrical RVLC requiring only a single code table and for an asymmetrical RVLC having short average code length are introduced. They compare favorably with other reversible codes such as B2 codes in several aspects.