Patent ID: 8457951
Filing Date: 2013-06-04
Classification: G10L

Abstract:
1. A method of detecting the presence of auxiliary information in an audio signal, wherein the auxiliary information is imparted onto the audio signal by emphasizing one or more frequency components of the audio signal, the method comprising: sampling the audio signal to create an audio block in a buffer having a buffer size; storing one or more components of a frequency domain representation of the audio block in a spectral characteristics table; receiving a subsequent sample of the audio signal; adjusting the stored components in the spectral characteristics table in accordance with elapsed time since generating the frequency domain representation to form a modified frequency domain representation; removing a spectral effect of an oldest sample in the audio block from the modified frequency domain representation stored in the spectral characteristics table; adding a spectral effect of the subsequent sample of the audio signal to the modified frequency domain representation stored in the spectral characteristics table to form an updated frequency domain spectrum in the spectral characteristics table; analyzing the updated frequency domain spectrum to determine emphasis of one or more frequency components; and determining auxiliary information corresponding to the emphasis of one or more frequency components.