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在MP3编解码器的设计中,前向MDCT与反向IMDCT是两个计算最为复杂的部分.提出了一种新的算法,对MDCT与IMDCT的实现进行优化,极大地降低了运算量.该算法将MDCT与IMDCT的计算分成三步实现:前处理,核心处理,后处理.其中,核心处理部分由MDCT与IMDCT共用,大大减少了对硬件电路的需求,降低了芯片成本. 相似文献
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DRA (Dynamic resolution adaptation) audio coding standard was shown to deploy transientlocalized MDCT to effectively suppress pre-echo artifacts and statistic allocation of codebooks to improve the compression efficiency of Huffman coding. Its quantizers and Huffman codebooks are designed in such a way that a signal path of 24 bits is provided throughout the codec so that high audio quality can be delivered if bit rate suffices. Although simple, it delivers state-of-the-arts compression efficiency as shown by five rounds of ITU-R BS.11116 compliant subjective listening tests. 相似文献
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MDCT和IMDCT凭借其在消除边界噪声、改善信号质量方面的优越性,广泛应用于高级音频编码标准框架中,同时,其也是编解码系统中计算复杂度最高的三大模块之一。在Clenshaw’s递归公式的基础上,采用关键单元分时复用、信号并行处理技术对共用递归中滤波处理模块进行改进,在总资源几乎不增加的条件下,使得总递归次数降至N^2/16+N/4,且模块化规则性好、结构性强;在硬件实现时,增加延时单元和适当控制逻辑以避免并行数据处理带来的多端口或多个存储单元的并行操作。最后,使用Synplify Pro8.5.1工具在Xilinx Virtex-E系列FPGA上对36点共用结构进行了验证。 相似文献
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Forward and inverse MDCT are two of the most computationally intensive operations in the MPEG audio coding standard. In this paper we derive sinusoidal recursive formulas for transforming kernels of the MDCT/MDST and IMDCT/IMDST. Then we efficiently implement MDCT/MDST and IMDCT/IMDST of the general length using the regressive structure derived from the sinusoidal recursive formulas. The proposed regular structure is particularly suitable for parallel VLSI realization. Our solution requires significantly less operations as well as less hardware compared with a recently proposed one. 相似文献
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This letter presents an algorithm for selecting a low delay for the modified discrete cosine transform (MDCT) and inverse MDCT (IMDCT). The implementation of conventional MDCT and IMDCT requires a 50% overlap‐add (OLA) for a perfect reconstruction. In the OLA process, an algorithmic delay in the frame length is employed. A reduced overlap window and MDCT/IMDCT phase shifting is used to reduce the algorithmic delay. The performance of the proposed algorithm is evaluated by applying the low‐delay MDCT to the G. 729.1 speech codec. 相似文献
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数字音频压缩中的变换编码算法 总被引:11,自引:3,他引:8
变换编码是音频压缩中的一个重要部分,文中叙述MPEG音频编码标准中的变换编码技术,包括改进余弦变换和反变换(MDCT和IMDCT)时域混叠抵消与自适应窗选择,详细推导了MDCT和IMDCT的快速算法。 相似文献