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

T. Moriya, A. Jin, N. Iwakami, T. Mori

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)


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.

Original languageEnglish
Title of host publication2000 IEEE Workshop on Speech Coding - Proceedings
Subtitle of host publicationMeeting the Challenges of the New Millennium
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages3
ISBN (Electronic)0780364163, 9780780364165
Publication statusPublished - 2000
Externally publishedYes
EventIEEE Workshop on Speech Coding - Delavan, United States
Duration: 2000 Sep 172000 Sep 20

Publication series

Name2000 IEEE Workshop on Speech Coding - Proceedings: Meeting the Challenges of the New Millennium


OtherIEEE Workshop on Speech Coding
Country/TerritoryUnited States


  • Bandwidth
  • Bit rate
  • Digital audio players
  • IEC
  • ISO
  • MPEG 4 Standard
  • Sampling methods
  • Signal design
  • Speech
  • Testing

ASJC Scopus subject areas

  • Signal Processing
  • Software


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