Audio frame loss concealment
First Claim
1. A frame loss concealment method, wherein a segment from a previously received or reconstructed 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 in the frequency domain to identify frequencies of sinusoidal components of the audio signal;
calculating a phase shift θ
kfor the identified sinusoidal components;
phase shifting the identified sinusoidal components of the prototype frame by the phase shift θ
k; and
creating the substitution frame by performing an inverse frequency transform of a frequency spectrum of the prototype frame after phase shifting the identified sinusoidal components of the prototype frame;
wherein phase shifting the identified sinusoidal components comprises shifting a phase of all spectral coefficients in the prototype frame included in an interval Mk around a sinusoid k by the phase shift θ
k;
wherein phases of spectral coefficients that are not phase shifted are randomized and the spectral coefficients that are not phase shifted include spectral coefficients in a gap outside the interval Mk; and
wherein a magnitude of the spectral coefficients is kept unchanged while the phases of the spectral coefficients are shifted.
1 Assignment
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Accused Products
Abstract
Concealing a lost audio frame of a received audio signal by performing a sinusoidal analysis of a part of a previously received or reconstructed audio signal, wherein the sinusoidal analysis involves identifying frequencies of sinusoidal components of the audio signal, applying a sinusoidal model on a segment of the previously received or reconstructed audio signal, wherein said segment is used as a prototype frame in order to create a substitution frame for a lost audio frame, and creating the substitution frame for the lost audio frame by time-evolving sinusoidal components of the prototype frame, up to the time instance of the lost audio frame, in response to the corresponding identified frequencies.
21 Citations
23 Claims
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1. A frame loss concealment method, wherein a segment from a previously received or reconstructed audio signal is used as a prototype frame in order to create a substitution frame for a lost audio frame, the method comprising:
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transforming the prototype frame into a frequency domain; applying a sinusoidal model to the prototype frame in the frequency domain to identify frequencies of sinusoidal components of the audio signal; calculating a phase shift θ
kfor the identified sinusoidal components;phase shifting the identified sinusoidal components of the prototype frame by the phase shift θ
k; andcreating the substitution frame by performing an inverse frequency transform of a frequency spectrum of the prototype frame after phase shifting the identified sinusoidal components of the prototype frame; wherein phase shifting the identified sinusoidal components comprises shifting a phase of all spectral coefficients in the prototype frame included in an interval Mk around a sinusoid k by the phase shift θ
k;wherein phases of spectral coefficients that are not phase shifted are randomized and the spectral coefficients that are not phase shifted include spectral coefficients in a gap outside the interval Mk; and wherein a magnitude of the spectral coefficients is kept unchanged while the phases of the spectral coefficients are shifted. - View Dependent Claims (2, 3, 17, 18, 19, 20, 21)
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4. An apparatus for creating a substitution frame for a lost audio frame, the apparatus comprising:
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a processor; and memory communicatively coupled to the processor, said memory comprising instructions executable by the processor, which cause the processor to; generate a prototype frame from a segment of a previously received or reconstructed audio signal; transform the prototype frame into a frequency domain; apply a sinusoidal model to the prototype frame in the frequency domain to identify frequencies of sinusoidal components of the audio signal; calculate a phase shift θ
k for the identified sinusoidal components;phase shift the identified sinusoidal components of the prototype frame by the phase shift θ
k; andcreate the substitution frame by performing an inverse frequency transform of a frequency spectrum of the prototype frame after phase shifting the identified sinusoidal components of the prototype frame; wherein phase shifting the identified sinusoidal components comprises shifting a phase of all spectral coefficients in the prototype frame included in an interval Mk around a sinusoid k by θ
k;wherein phases of spectral coefficients that are not phase shifted are randomized and the spectral coefficients that are not phase shifted include spectral coefficients in one or more gaps between intervals in the interval Mk; and wherein a magnitude of the spectral coefficients is kept unchanged while the phases of the spectral coefficients are shifted. - View Dependent Claims (5, 6, 22, 23)
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7. 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:
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transforming the prototype frame into a frequency domain; applying a sinusoidal model to the prototype frame in the frequency domain to identify a frequency of a sinusoidal component of the audio signal; calculating a phase shift θ
k for the sinusoidal component;phase shifting the sinusoidal component by the phase shift θ
k; andcreating the substitution frame by performing an inverse frequency transform of a frequency spectrum of the prototype frame after phase shifting the sinusoidal component of the prototype frame; wherein phase shifting the sinusoidal component comprises shifting a phase of all spectral coefficients in the prototype frame included in an interval Mk around a sinusoid k by the phase shift θ
k;wherein phases of spectral coefficients that are not phase shifted are randomized and the spectral coefficients that are not phase shifted include spectral coefficients in a gap outside the interval Mk; and wherein a magnitude of the spectral coefficients is kept unchanged while the phases of the spectral coefficients are shifted. - View Dependent Claims (8, 9, 10, 11)
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12. An apparatus for creating a substitution frame for a lost audio frame, the apparatus comprising:
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a processor; and memory communicatively coupled to the processor, said memory comprising instructions executable by the processor, which cause the processor to; generate a prototype frame from a segment of a previously synthesized audio signal; transform the prototype frame into a frequency domain; apply a sinusoidal model to the prototype frame in the frequency domain to identify a frequency of a sinusoidal component of the audio signal; calculate a phase shift θ
k for the sinusoidal component;phase shift the sinusoidal component of the prototype frame by the phase shift θ
k; andcreate the substitution frame by performing an inverse frequency transform of a frequency spectrum of the prototype frame after phase shifting the sinusoidal component of the prototype frame; wherein phase shifting the sinusoidal component comprises shifting a phase of all spectral coefficients in the prototype frame included in an interval Mk around a sinusoid k by the phase shift θ
k;wherein phases of spectral coefficients that are not phase shifted are randomized and the spectral coefficients that are not phase shifted includes spectral coefficients in a gap outside the interval Mk; and wherein a magnitude of the spectral coefficients is kept unchanged while the phases of the spectral coefficients are shifted. - View Dependent Claims (13, 14, 15, 16)
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Specification