【摘要】 使码字能双向解码和构造同步字是当前提高变长码(VLC)自身容错能力的最主要两种方法,其中又分别以可逆变长码(RVLC)和同步变长码(SVLC)为主要代表。在SVLC中,找到了一类结合了这两种方法的VLC,它是移位对称数为2的整数次幂的SVLC。如果在用该码编码后的序列前中填加一同步字,则新序列可实现双向解码,故我们称之为准可逆同步变长码(QRSVLC)。QRSVLC的编码效率高于对称的RVLC,与非对称的RVLC相差无几。它还具有每个码字都包含同步字等优点。更多还原

【Abstract】 Two major methods used to improve the error resiliency of VLC,are to make codeword bi-directionally decodable and to construct sync word.The reversible variable length code(RVLC) and synchronized variable length codes(SVLC) are two representatives of the application of these methods.We find one way to combine these two methods in the framework of SVLC.It is a SVLC that its shift symmetry is the integral power of 2.By adding an extra sync codeword before the coded sequence,the new sequence can be decoded bi-directionally.Therefore we name it quasi-reversible synchronized variable length code(QRSVLC).The coding efficiency of QRSVLC is higher than symmetric RVLC,but in par with asymmetric RVLC.The other advantage of QRSVLC is that each codeword of QRSVLC contains a sync codeword.更多还原