Patent ID: 8117027
Filing Date: 2012-02-14
Classification: G10L,H04B,H04H

Abstract:
1. Method for introducing information into a data stream comprising data about spectral values representing a short-term spectrum of an audio signal, the method comprising: processing the data stream to obtain the spectral values of the short-term spectrum of the audio signal; combining the information with a spread sequence to obtain a spread information signal; generating a spectral representation of the spread information signal to obtain a spectral spread information signal; establishing psychoacoustic maskable noise energy as a function of frequency for the short-term spectrum of the audio signal, the psychoacoustic maskable noise energy being variable over frequency, wherein the psychoacoustic maskable noise energy is smaller or the same as the psychoacoustic masking threshold of the short-term spectrum; weighting the spectral spread information signal by using the established psychoacoustic maskable noise energy being varying over frequency to generate a weighted information signal, wherein the energy of the introduced information is varying over frequency and is substantially equal to or below the psychoacoustic masking threshold; summing the weighted information signal with the spectral values of the short-term spectrum of the audio signal to obtain sum spectral values comprising the short-term spectrum of the audio signal and the information; and processing the sum spectral values to obtain a processed data stream comprising the data about the spectral values of the short-term spectrum of the audio signal and the information to be introduced, wherein the processing the data stream, the combining, the generating, the establishing, the weighting, processing the sum spectral values or the summing is performed using a processor wherein the spectral values of the data stream are quantized such that the noise energy introduced by quantizing is smaller than the psychoacoustic masking threshold by a predetermined amount and wherein, in the step of establishing an energy corresponding to the predetermined amount is established: and wherein in the step of weighting the spectral values of the spectral representation of the spread information signal are set such that they have an energy corresponding to the predetermined amount.