Design of an MPEG-4 general audio coder for improving speech quality

Author

Moriya, Takehiro ; Jin, Akio ; Iwakami, N. ; Mori, Takeshi

Author_Institution

NTT Labs., Tokyo, Japan

fYear

2000

fDate

2000

Firstpage

139

Lastpage

141

Abstract

This paper proposes a design for an ISO/IEC MPEG-4 general audio encoder to improve the speech quality at low bit rates. The main contributions to the improvement are using i) a higher sampling rate to get higher time resolution for a given frame length and ii) adaptive preprocessing to reduce the bandwidth. Listening tests at 8 and 16 kbit/s showed that compared with a conventional audio coder and a speech-specific coder, the proposed coder provided better speech quality than the conventional audio coder (MP3) while keeping the quality for music. For speech signals, however, the speech-specific coder (MPEG-4 CELP) produced significantly better quality than the audio coders. The proposed design will be especially useful for low-bit-rate audio-visual delivery applications which may include both speech and music signals

Keywords

audio coding; audio-visual systems; linear predictive coding; music; signal resolution; signal sampling; speech coding; 16 kbit/s; 8 kbit/s; CELP; ISO/IEC audio encoder; MPEG-4 general audio coder; adaptive preprocessing; audio-visual delivery applications; higher sampling rate; higher time resolution; listening tests; low bit rate coding; music signals; speech quality improvement; Bandwidth; Bit rate; Digital audio players; IEC; ISO; MPEG 4 Standard; Sampling methods; Signal design; Speech; Testing;

fLanguage

English

Publisher

ieee

Conference_Titel

Speech Coding, 2000. Proceedings. 2000 IEEE Workshop on

Conference_Location

Delavan, WI

Print_ISBN

0-7803-6416-3

Type

conf

DOI

10.1109/SCFT.2000.878429

Filename

878429