High quality audio communication is a current challenge addressed by the standardisation committees. In this context, ITU and MPEG recently issued standards for high quality coding of both speech and music contents. Transform coding is used and allows quality commensurate with bit rates regardless of the audio content. Up to now, only constant transform sizes were used in these coding schemes since time varying transform needed lookahead for perfect reconstruction, hence adding further delay. In this paper we demonstrate how variable transform sizes can be used without affecting the coding delay. Based on the filterbank theory, a framework avoiding lookahead is presented. The quality improvement offered by the proposed solution is illustrated in the context of MPEG-4 Enhanced Low Delay AAC.
Authors:
Kovesi, Balazs; Philippe, Pierrick; Virette, David
Affiliation:
France Telecom
AES Convention:
124 (May 2008)
Paper Number:
7333
Publication Date:
May 1, 2008
Subject:
Low Bit-Rate Audio Coding
Click to purchase paper as a non-member or you can login as an AES member to see more options.
No AES members have commented on this paper yet.
To be notified of new comments on this paper you can subscribe to this RSS feed. Forum users should login to see additional options.
If you are not yet an AES member and have something important to say about this paper then we urge you to join the AES today and make your voice heard. You can join online today by clicking here.