标题: MPEG-4 HE-AAC中耦合编码之设计
Design of Coupling Coding in MPEG-4 HE-AAC
作者: 张家铭
Chia-Ming Chang
刘启民
李文杰
Chi-Min Liu
Wen-Chieh Lee
资讯科学与工程研究所
关键字: 耦合编码;耦合转换;Coupling Coding;HE-AAC;SBR
公开日期: 2005
摘要: SBR的耦合编码机制乃藉由转换资料的纪录方式,以去除资料的相关性,达到节省位元的目的。然而,碍于耦合编码的先天限制,若干原先独立的资讯必须被双声道共用。由于资讯的共用,产生两项关系到品质的设计议题,其中包含时频格子与啾声参数。再者,量化处理所造成的品质衰退的风险,也必须进一步的审视。本论文考虑可能产生的人工缺陷,来考量共用参数的决定,并提出一个兼顾高频品质及需求位元数的耦合转换方法。在品质的量测上,除了主观的聆听评量之外,并采用ITU所发展的PEAQ测试系统来评估音讯压缩后的改良程度。
The coupling coding in SBR is adapted to transform the data domain to de-correlation and save more bits. However, because of the inherent constraint of the coupling coding, some side information need to be shared by the stereo channels. There are two considerable issues related to quality due to the sharing, including the determining of the shared T/F grid and the shared chirp factor. On the other hand, the quantization process causes of the risk of quality degradation also need to be inspected. This thesis considers the possible artifacts to examine the decision of the shared parameter, and proposes a coupling decision method for the tradeoff between high band quality and demand bits. Both subjective and objective tests are conducted to check the quality improvement. The objective test measures used is the recommendation system by ITU-R Task Group 10/4.
URI: http://140.113.39.130/cdrfb3/record/nctu/#GT009317600
http://hdl.handle.net/11536/78811
显示于类别:Thesis


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