FRAME LOSS CONCEALMENT FOR THE LOW-FREQUENCY EFFECTS CHANNEL

Claims

1. A method for generating a replacement frame for a lost audio frame of an audio signal, comprising the steps of determine an audio filter based on discrete samples of a valid audio frame preceding the lost audio frame; generate a replacement frame based on an audio filter and discrete samples of a valid audio frame preceding the lost audio frame; downsampling the discrete samples of the valid audio frame before generating the replacement discrete samples of the replacement frame; and perform upsampling of the replacement discrete samples of the replacement frame after generating the replacement frame.

2. The method according to claim 1, wherein the step of generating a replacement frame based on an audio filter and discrete samples of a reliable audio frame includes a step of initializing the filter memory of said audio filter with discrete samples of a reliable audio frame.

3. The method according to claim 1 or 2, further comprising the step of determining a modified audio filter based on said audio filter, wherein the modified audio filter replaces said audio filter, and wherein generating a replacement frame based on the audio filter includes generating a replacement frame based on the modified audio filter and discrete samples of a valid audio frame.

4. The method of claim 3, wherein the step of determining the modified audio filter includes narrowing the bandwidth.

5. The method according to any one of the preceding claims, wherein said audio filter is an all-pole filter.

6. The method according to any one of the preceding claims, wherein said audio filter is obtained from an all-pass filter operating on at least a discrete sample of a valid frame.

7. The method according to claim 6, comprising the step of determining said audio filter based on the denominator of the polynomial of the transfer function of the all-pass filter.

8. The method according to any one of the preceding claims, comprising the step of determining the magnitudes and frequencies of the poles of said audio filter using a root finding method.

9. A system for generating a replacement frame for a lost audio frame of an audio signal, comprising: one or more processors; and a non-transitory machine-readable medium storing instructions that, when executed by one or more processors, cause one or more processors to perform the operations of any one of paragraphs 1-8.

10. A non-transitory machine-readable medium storing instructions that, when executed by one or more processors, cause one or more processors to perform the operations of any one of paragraphs 1-8.