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Enhanced Pre echo Control Algorithm for MPEG Audio Coders  

Lee Chang-Joon (Dept. of Electrical & Electronic Eng., Yonsei University)
Lee Jae-Seong (Dept. of Electrical & Electronic Eng., Yonsei University)
Park Young-Cheol (Computer and Telecommunications Eng. Division, Yonsei University)
Publication Information
Journal of Broadcast Engineering / v.11, no.2, 2006 , pp. 191-199 More about this Journal
Abstract
This paper presents an efficient pre echo control scheme for MPEG Audio coders based on the psychoacoustic model II (PAM-II). Pre echo control is the final step for the calculation of masking threshold in the PAM II. It is to minimize the spread of quantization error over the processing frame. In the conventional encoders, pre echo is reduced by restricting the estimated masking threshold not to exceed the one obtained in the previous frame. The conventional method performs pre echo control not only for short blocks but also for long blocks, which lowers the masking threshold in long blocks and, in turn, increases the quantization noise level of corresponding blocks. This paper proposes an efficient pre echo control process. The test result shows a mean enhancement of more than 0.4 especially for complex signals on the ITU R 5 point audio impairment scale.
Keywords
pre-echo; PAM; MPEG Audio;
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  • Reference
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