서지주요정보
G.729A와 SMV 음성 부호화기를 위한 파라미터 직접 변환 방식의 상호부호화 알고리즘에 관한 연구 = A novel transcoding algorithm for G.729A and SMV speech codecs via direct parameter transformation
서명 / 저자 G.729A와 SMV 음성 부호화기를 위한 파라미터 직접 변환 방식의 상호부호화 알고리즘에 관한 연구 = A novel transcoding algorithm for G.729A and SMV speech codecs via direct parameter transformation / 장달원.
저자명 장달원 ; Jang, Dal-Won
발행사항 [대전 : 한국과학기술원, 2003].
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등록번호

8014619

소장위치/청구기호

학술문화관(문화관) 보존서고

MEE 03121

SMS전송

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초록정보

In this thesis, a novel transcoding algorithm for G.729A and Seletable Mode Vocoder (SMV) speech codecs is proposed. As in tandem transcoding which transcodes by synthesizing speech via decoding of the bit stream using the decoder of the source codec and then re-encoding using the encoder of the target codec, the proposed algorithm directly transforms the parameters of source codec to those of the target codec without performing the encoding and decoding processes twice and completely synthesizing the speech in process. Since G.729A and SMV are both based on Code Excited Linear Prediction (CELP), the parameters of both are similar. Therefore the parameters of one can be transformed to those of the other directly. The transformation of these parameters is the main theme of this thesis. Line Spectral Pairs (LSP) are converted via linear interpolation. The search space for pitch delay of target codec is confined to a small interval around the pitch delay of source codec. Whereas a fixed frame rate is used in G.729A, SMV varies the transmission rate of each frame depending on both the characteristic of the frame and the input from the network. When transcoding from G.729A to SMV, a novel rate selection algorithm is used to determine the characteristic of the frame and the frame rate. The transcoder is implemented using C programming language. The program works on the Win32 platform but uses fixed-point format for the digital signal processor (DSP) implementation. The performance of proposed algorithm is evaluated using various measures. The evaluation results show that the speech quality of proposed algorithm is equivalent to that of tandem transcoding algorithm while requiring less computational load and shorter delay.

서지기타정보

서지기타정보
청구기호 {MEE 03121
형태사항 viii, 63 p. : 삽도 ; 26 cm
언어 한국어
일반주기 저자명의 영문표기 : Dal-Won Jang
지도교수의 한글표기 : 유창동
지도교수의 영문표기 : Chang-D. Yoo
학위논문 학위논문(석사) - 한국과학기술원 : 전기및전자공학전공,
서지주기 참고문헌 : p. 61-63
주제 상호 부호화
G.729A
SMV
음성부호화기
Transcoding
G.729A
SMV
Speech codec
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