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A Preprocessing Approach to Improving the Quality of the Music Produced by the EVRC  

남영한 (와이더덴닷컴(주) 기술연구소)
하태균 (와이더덴닷컴(주) 기술연구소)
전윤호 (와이더덴닷컴(주) 기술연구소)
김재수 (와이더덴닷컴(주) 기술연구소)
박섭형 (한림대학교 정보통신공학부)
Publication Information
The Journal of Korean Institute of Communications and Information Sciences / v.28, no.5C, 2003 , pp. 476-485 More about this Journal
Abstract
This paper proposers a preprocessing approach to improving the quality of the music produced by the EVRC(enhanced variable rate codec) which is one of the CDMA(Code Division Multiple Access) voice codecs. Since the EVRC is optimized only for speech signals, it can deteriorate the quality of the music passed through it. One of the problems with the EVRC-coded music is time-clipping, which usually occurs when subsequent frames are encoded at Rate l/8. Since the EVRC determines the bit rate for an input frame based on the long-term prediction gain, we increase the long-term prediction gain in order for the most of the frames to be encoded at Rate 1 or Rate 1/2. Experimental results show that the approach works well on music signals and the number of time-clipped frames is considerably reduced.
Keywords
EVRC; preprocessing; music enhancement; pitch harmonics enhancement; time-clipping;
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