(19) United States
(12) Patent Application Publication (io) Pub. No.: US 2003/0231774 Al
Schildbach et al. (43) Pub. Date: Dec. 18,2003
(54) METHOD AND APPARATUS FOR
PRESERVING MATRIX SURROUND
INFORMATION IN ENCODED AUDIO/VIDEO
(76) Inventors: Wolfgang A. Schildbach, Seattle, WA (US); Kenneth Edward Cooke, Seattle, WA (US)
SCHWABE, WILLIAMSON & WYATT, P.C.
PACWEST CENTER, SUITES 1600-1900
1211 SW FIFTH AVENUE
PORTLAND, OR 97204 (US)
(21) Appl. No.: 10/295,582
(22) Filed: Nov. 14, 2002
Related U.S. Application Data
(60) Provisional application No. 60/375,289, filed on Apr. 23, 2002.
A method and apparatus for preserving matrix-surround information in encoded audio/video includes a receiver operative to receive matrix-surround encoded audio signals via a modem, separate the audio signals into a frequency spectrum having discrete audio frequencies, and determine a cutoff threshold used to encode the matrix-surround encoded audio signals. The method and apparatus further includes a decoder operative to decode a first set of the audio frequencies below the determined cutoff threshold using a first matrix-surround preserving audio encoding method and to decode a second set of audio frequencies above the cutoff threshold using a second non matrix-surround preserving audio encoding method.