Today's standard audio coders are mostly based on subband coding, using filter banks for the spectral analysis and decomposition of the audio signal. So far the applications of these coders were mostly in areas, where signal delay is not of high importance, as in broadcast or storage. Recently the demand for high quality teleconferencing or virtual presence scenarios is increasing. Here the end-to-end signal delay becomes more important, and it turns out that many wide-spread standard audio coders have too much encoding/decoding delay for these applications. Hence it would be interesting to see if we can reduce the delay of these coders. One of the main sources of their delay is the system delay of their filter banks. The talk will describe ways to design new filter banks which have a lower system delay while still keeping the same number of subbands and comparable frequency responses, with only a slight increase in computational complexity. These new filter banks can then be used to replace the previous, "orthogonal" filter banks, to obtain coders with a reduced encoding/decoding delay. An example is the MPEG Enhanced Low Delay AAC coder.
Dr. Gerald Schuller is a full professor at the Insitute for Media Technology of the Technical University of Ilmenau, since 2008, and head of the Audio Coding for Special Applications group of the Fraunhofer Institute for Digital Media Technology in Ilmenau, Germany, since January 2002. Before joining the Fraunhofer Institute, he was a Member of Technical Staff at Bell Laboratories, Lucent Technologies, and Agere Systems, a Lucent Spin-off, from 1998 to 2001. There he worked in the Multimedia Communications Research Laboratory. He received his Diplom degree in Electrical Engineering from the Technical University of Berlin in 1989, and his Ph.D. (Dr.-Ing.) degree from the University of Hanover in 1997, studied at the Massachusetts Institute of Technology in 1989/90 and at The Georgia Institute of Technology in 1993. He was Associate Editor of the IEEE Transactions on Speech and Audio Processing from 2002 until 2006, and is Associate Editor of the IEEE Transactions on Signal Processing since 2006, and of the IEEE Transactions on Multimedia since 2008. He is recipient of the 2006 IEEE Best Paper Award in the Audio and Electroacoustics Area. Web site: http://www.idmt.fhg.de/schuller.html