Decoder for audio signal including generic audio and speech frames
A method for decoding audio frames includes producing a first frame of coded audio samples, producing at least a portion of a second frame of coded audio samples, generating audio gap filler samples based on parameters representative of a weighted segment of the first frame of coded audio samples or a weighted segment of the portion of the second frame of coded audio samples, and forming a sequence including the audio gap filler samples and the portion of the second frame of coded audio samples.
1. A method for decoding audio frames, the method comprising:
producing, using a first decoding method, a first frame of coded audio samples;
producing, using a second decoding method, at least a portion of a second frame of coded audio samples;
generating audio gap filler samples based on parameters representative of a weighted segment of the first frame of coded audio samples or a weighted segment of the portion of the second frame of coded audio samples;
forming a sequence including the audio gap filler samples and the portion of the second frame of coded audio samples; and
generating the audio gap filler samples based on parameters representative of both the weighted segment of the first frame of coded audio samples and the weighted segment of the portion of the second frame of coded audio samples;
wherein the parameters are based on an expression:
ŝ g =α·ŝ s (− T 1 )+β· ŝ a ( T 2 )
wherein α is a first weighting factor of a segment of the first frame of coded audio samples ŝ s (−T 1 ), β is a second weighting factor for a segment of the portion of the second frame of coded audio samples ŝ α (T 2 ), and ŝ s corresponds to the audio gap filler samples.
2. The method of claim 1 further comprising forming the sequence including the first frame of coded audio samples, wherein the audio gap filler samples at least partially fill an audio gap between the first frame of coded audio samples and the portion of the second frame of coded audio samples.
3. The method of claim 1 , wherein:
the weighted segment of the first frame of coded audio samples includes a first weighting parameter and a first index for the weighted segment of the first frame of coded audio samples; and
the weighted segment of the portion of the second frame of coded audio samples includes a second weighting parameter and a second index for the weighted segment of the portion of the second frame of coded audio samples.
4. The method of claim 3 , wherein:
the first index specifies a first time offset from the audio gap filler sample to a corresponding sample in the first frame of coded audio samples; and
the second index specifies a second time offset from the audio gap filler sample to a corresponding sample in the portion of the second frame of coded audio samples.
5. The method of claim 3 , wherein:
the first index is based on a correlation between a segment of the first frame of coded audio samples and a segment of reference audio gap samples in the sequence of frames; and
the second index is based on a correlation between a segment of the portion of the second frame of coded audio samples and the segment of reference audio gap samples.
6. The method of claim 1 wherein the parameters are based on a distortion metric that is a function of a set of reference audio gap samples, wherein the distortion metric is a squared error distortion metric.
7. The method of claim 1 wherein the parameters are based on a distortion metric that is a function of a set of reference audio gap samples, wherein the distortion metric is based on an expression:
D=|s g −ŝ g | T ·|s g −ŝ g |
where s g is representative of the set of reference gap filler samples.
8. The method of claim 1 further comprising producing the portion of the second frame of coded audio samples using a generic audio coding method.
9. The method of claim 8 further comprising producing the first frame of coded audio samples using a speech coding method.
10. The method of claim 1 , wherein the parameters are based on a distortion metric that is a function of a set of the reference gap filler samples.
11. The method of claim 1 further comprising producing the portion of the second frame of coded audio samples using a generic audio coding method.
12. The method of claim 11 further comprising producing the first frame of coded audio samples using a speech coding method.
13. The method of claim 1 , further comprising generating the audio gap filler samples based on parameters selected to reduce distortion between the audio gap filler samples and a set of reference audio gap samples.