[mus422] Lecture on Monday Jan 25th at 12:15 Please plan to attend!

[Marina Bosi]

Cosine Modulated Filterbanks and Bases -
A Historical Perspective.









 
The problem of developing time-frequency representations has received
considerable attention in the Engineering, Mathematics and


Scientific literature. Depending on the application, there are various
properties of such a representation which are important. One of the most


interesting and challenging problems is to create a representation that is
an orthogonal basis and has good time-frequency localization. Such
representations are incredibly useful in signal compression.





Until the latter part of the 1970's there were no known solutions to this
problem. However, starting in the late 1970's, inspired by the


development of Quadrature Mirror Filters, researchers

 found first approximate, and then exact solutions which were both
computationally
efficient, and provided excellent time-frequency localization. The
development of solutions and extensions happened almost simultaneously
within the Signal Processing community, and the Mathematics community,
with some cross pollination of ideas, but in some cases completely
independently.  

In this talk I will walk through the historical development of the
particular class of computationally efficient solutions called Cosine
Modulated Filterbanks, or Local Cosine Bases, which have become ubiquitous
in audio compression. My goal is to provide a background to the problem,
the key ideas that inspired solutions, and also point out the various
dependent and independent developments, partially disguised under
different names, that are essentially identical.

 

 

John Princen graduated with a B. Eng. in Electrical Engineering (1984),
and an M. Eng. in Digital Signal Processing (1986) from RMIT, Australia,
and a PhD in the area of Computer Vision (1990) from the University of
Surrey, UK.

Since then he has held positions at Telecom Australia Research Labs, Bell
Labs in Murray Hill, and Silicon Graphics in Mountain View. He is
currently a Vice President at BroadOn Communications Corp, Mountain View,
CA where he directs a team working on hardware and software for consumer
products. In the audio community he is best known for the development of
what is now known as the MDCT. The MDCT is a core part of many audio
compression systems, including MP3, ATRAC, AC3 and AAC.

 

 

Marina Bosi

Consulting Professor, Department of Music

Stanford University

 

Computer Center for Research in Music and Acoustics

The Knoll,  660 Lomita Court

Stanford, California 94305-8180, USA

http://ccrma.stanford.edu

mbosi at stanford.edu

 

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