Patent ID: 7555432
Filing Date: 2009-06-30
Classification: G10L

Abstract:
1. A method of embedding data in a host audio signal, comprising: defining a set of frames of said host audio signal; for each frame, determining a plurality of masked frequencies, those being spectral points having a power level below a masking threshold for the frame; selecting the two most commonly occurring masked frequencies f modifying a representation of each frame, using an audio steganography processor, at said masked frequencies f excluding frames with less than a minimum number of spectral points having a power level below the masking threshold for the frame; and normalizing the sound pressure level of each frame prior to determining said masking threshold; wherein said masking threshold for each frame varies in level with frequency, and wherein said modifying includes obtaining a cepstrum of each frame and modifying the frame cepstrum to produce complementary changes of the spectrum at said masked frequencies f