Method and apparatus for controlling audio frame loss concealment
AssigneeTelefonaktiebolaget LM Ericsson (publ)
InventorsStefan BRUHN, Jonas SVEDBERG
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Abstract
In accordance with an example embodiment of the present invention, disclosed is a method and an apparatus thereof for controlling a concealment method for a lost audio frame of a received audio signal. A method for a decoder of concealing a lost audio frame comprises detecting in a property of the previously received and reconstructed audio signal, or in a statistical property of observed frame losses, a condition for which the substitution of a lost frame provides relatively reduced quality. In case such a condition is detected, the concealment method is modified by selectively adjusting a phase or a spectrum magnitude of a substitution frame spectrum.
Claims1
A frame loss concealment method, wherein a segment of a previously synthesized audio signal is used as a prototype frame in order to create a substitution frame for a lost audio frame, the method comprising:
- transforming the prototype frame into a frequency domain;
- applying a sinusoidal model to the prototype frame to identify the frequency of a sinusoidal component of the audio signal;
- calculating a phase shift θk for the sinusoidal component;
- shifting a phase of all spectral coefficients in the prototype frame included in an interval Mk around a sinusoid k by the phase shift θk while retaining a magnitude of those spectral coefficients;
- randomizing phases of spectral coefficients that are not phase shifted;
- and
- creating the substitution frame by performing an inverse frequency transform of a frequency spectrum of the prototype frame.
Dependencies are inferred from the claim text.