可逆变长码以其出色的抗误码扩散的能力而被近来的视频压缩标准 (H.2 6 3++和 MPEG- 4 )所采纳。为了进一步提高可逆变长码的效率 ,提出了一种新的可逆变长码的构造算法。该算法中使用二叉树结构进行码字的构造 ,并分析了二叉树中可逆变长码的构造条件。提出了一个代价函数 ,用它来决定各层中叶子节点的数量 ,并且在选择叶子节点的位置时 ,充分考虑到不同叶子结点位置的组合对于下层可用节点数目的影响。相对于现有的其它算法 ,这种算法能够构造出更为高效的可逆变长码 ,并且算法本身非常简单 ,易于实现。 Reversible variable length codes are adopted by recent video compression standards (H.263 + and MPEG-4) for their excellent ability to resist error diffusion. In order to further improve the efficiency of the reversible variable length code, a new algorithm for constructing a reversible variable length code is proposed. This algorithm uses the binary tree structure to construct the codeword, and analyzes the construction condition of the reversible variable length code in the binary tree. A cost function is proposed to determine the number of leaf nodes in each layer. When the position of leaf nodes is chosen, the effect of the combination of different leaf nodes on the number of available nodes in the lower layer is fully considered. Compared with other existing algorithms, this algorithm can construct a more efficient and reversible variable length code, and the algorithm itself is very simple and easy to implement.