中文摘要：

面向音频多声道虚拟环绕处理的应用，提出一种改进离散余弦变换（MDCT）域的头相关传输函数（HRTF）高效滤波算法．通过MDCT的多相滤波结构分解，得到MDCT域滤波矩阵，再根据矩阵稀疏表征的思想，以及HRTF的频谱动态范围大的特点，对MDCT滤波矩阵进行动态邻域优化，有效地提高了MDCT域滤波的效率．通过大量的实验对比表明：该方法较以往的MDCT域滤波方法大大降低了运算复杂度，且保持滤波结果的一致性；该动态邻域算法与传统时域、频域处理方法相比，主观质量差异较小；该方法大大降低了虚拟环绕处理的算法复杂度，尤其适合采用MDCT编码的压缩音频格式．

英文摘要：

An efficient filtering algorithm of multichannel virtual surround processing in modified discrete cosine transform （MDCT） was proposed. The MDCT filter bank can be represented in a polyphase structure and further derived to a high order matrix representation. By using the property of sparse matrix representation and the large dynamic range of head-related transfer function （HRTF）, an adaptive neighbor- hood algorithm was presented for fast filtering with HRTF in the MDCT domain. The width of a neigh-borhood can be adjusted according to the spectrum of HRTF in MDCT domain. Experimental results show that the proposed algorithm greatly reduced the implementation cost, and maintained same filtering quali- ty. In order to compare with different muhichannel virtual surround processing methods, a subjective listening test was conducted. The listening results reveal that the proposed approach can achieve basically same subjective quality as the traditional filtering methods. The complexity analysis of the virtual surround processing methods indicates that the proposed filtering algorithm of HRTF consumes minimal calculation, which is particularly suitable for audio compressed in MDCT format.