The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 16, 2014
Filed:
Mar. 07, 2012
Timothy B. Terriberry, Mountain View, CA (US);
Jean-marc Valin, Montreal, CA;
Timothy B. Terriberry, Mountain View, CA (US);
Jean-Marc Valin, Montreal, CA;
Abstract
Embodiments are directed to an audio coding scheme implemented in a codec that eliminates birdie artifacts generated by transform coding methods. A frequency coefficient spreading method invertibly rotates a spectrum of coefficient values based on a defined rotation angle, The rotated spectrum is then quantized, and the rotation operation is then reversed so that a previously sparse spectrum (i.e., one with few non-zero values) becomes one that has many non-zero values. The method arranges the coefficients for a particular partition into a linear array and computes a gain factor for the partition. A rotation angle of between 0 and π/4 for successive pairs of coefficients of the linear array based on the gain factor is then derived. One or more rotation operations are then applied to successive pairs of coefficients in the linear array using a specific rotation angle and a stride length for each rotation operation.