Method and device for decoding signal

• US 10,236,002 B2
• Filed: 10/18/2017
• Issued: 03/19/2019
• Est. Priority Date: 12/06/2012
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: Liu, Zexin, Qi, Fengyan, Miao, Lei
• Primary Examiner(s): Yen, Eric
• Application Number:
  US15/787,563
• Publication Number:
  US 20180040326A1
• Time in Patent Office: 517 Days
• CPC Class Codes: G10L 19/002 Dynamic bit allocation for perceptual audio coders G10L19/032
• CPC Class Codes: G10L 19/005 Correction of errors induced by the transmission channel, if related to the coding algorithm
• CPC Class Codes: G10L 19/0204 using subband decomposition
• CPC Class Codes: G10L 19/028 Noise substitution, i.e. substituting non-tonal spectral components by noisy source comfort noise for discontinuous speech transmission G10L19/012

Abstract

A method and device for decoding a signal. The method for decoding a signal includes: obtaining spectral coefficients of sub-bands from a received bitstream by means of decoding; classifying sub-bands in which the spectral coefficients are located into a sub-band with saturated bit allocation and a sub-band with unsaturated bit allocation; performing noise filling on a spectral coefficient that has not been obtained by means of decoding and is in the sub-band with unsaturated bit allocation, so as to restore the spectral coefficient that has not been obtained by means of decoding; and obtaining a frequency domain signal according to the spectral coefficients obtained by means of decoding and the restored spectral coefficient. Therefore, a sub-band with unsaturated bit allocation in a frequency domain signal may be obtained by classification, thereby improving signal decoding quality.

Claims

1. A method for decoding an audio signal, comprising:

decoding, by a decoder comprising a processor, a bitstream representing the audio signal to obtain at least one spectral coefficient of a current frame of the audio signal, wherein the current frame comprises a plurality of sub-bands;

classifying, by the decoder, whether a sub-band of the current frame is a bit allocation un-saturated sub-band or a bit allocation saturated sub-band according to an average quantity of allocated bits per spectral coefficient of the sub-band;

when the sub-band is classified as the bit allocation un-saturated sub-band, reconstructing, by the decoder, at least one spectral coefficient of the sub-band; and

obtaining, by the decoder, a frequency domain audio signal according to the obtained at least one spectral coefficient of the current frame and the reconstructed at least one spectral coefficient of the sub-band.

2. The method according to claim 1, wherein classifying whether the sub-band is the bit allocation un-saturated sub-band or the bit allocation saturated sub-band comprises:

comparing the average quantity of allocated bits per spectral coefficient of the sub-band with a classification threshold; and

classifying the sub-band as the bit allocation un-saturated sub-band when the average quantity of allocated bits per spectral coefficient of the sub-band is less than the classification threshold.

3. The method according to claim 2, wherein the average quantity of allocated bits per spectral coefficient of the sub-band is a ratio of a quantity of bits allocated for the sub-band to a quantity of spectral coefficients in the sub-band.

4. The method according to claim 2, wherein the method further comprising:

classifying another sub-band of the current frame as a bit allocation saturated sub-band when an average quantity of allocated bits per spectral coefficient of the another sub-band is not less than the classification threshold.

5. The method according to claim 2, wherein the classification threshold is greater than 0.

6. The method according to claim 1, wherein the reconstructed at least one spectral coefficient of the sub-band had been filled with 0 when the bitstream is decoded.

7. The method according to claim 2, wherein the method further comprising:

classifying another sub-band of the current frame as a bit allocation un-saturated sub-band, wherein each spectral coefficient of the another sub-band had been filled with 0 when the bitstream is decoded.

8. A method for decoding an audio signal, comprising:

decoding, by a decoder, a bitstream representing the audio signal to obtain at least one spectral coefficient of a current frame of the audio signal, wherein the current frame comprises a plurality of sub-bands;

calculating, by the decoder, an average quantity of allocated bits per spectral coefficient of a sub-band of the current frame;

comparing, by the decoder, the average quantity of allocated bits per spectral coefficient of the sub-band with a classification threshold;

when the average quantity of allocated bits per spectral coefficient of the sub-band is less than the classification threshold, reconstructing, by the decoder, at least one spectral coefficient of the sub-band; and

obtaining, by the decoder, a frequency domain audio signal according to the obtained at least one spectral coefficient of the current frame and the reconstructed at least one spectral coefficient of the sub-band.

9. The method according to claim 8, wherein the average quantity of allocated bits per spectral coefficient of the sub-band is a ratio of a quantity of bits allocated for the sub-band to a quantity of spectral coefficients in the sub-band.

10. The method according to claim 8, wherein the classification threshold is greater than 0.

11. The method according to claim 8, wherein the reconstructed at least one spectral coefficient of the sub-band had been filled with 0 when the bitstream is decoded.

12. The method according to claim 8, further comprising:

when the average quantity of allocated bits per spectral coefficient of the sub-band is no less than the classification threshold, no reconstructing is performed on the sub-band.

13. A decoder for decoding an audio signal, comprising:

a non-transitory memory for storing computer-executable instructions; and

a processor operatively coupled to the non-transitory memory, the processor being configured to execute the computer-executable instructions to;

decode a bitstream representing the audio signal to obtain at least one spectral coefficient of a current frame of the audio signal, wherein the current frame comprises a plurality of sub-bands;

classify, according to an average quantity of allocated bits per spectral coefficient of a sub-band of the current frame, whether the sub-band is a bit allocation un-saturated sub-band or a bit allocation saturated sub-band;

when the sub-band is classified as the bit allocation un-saturated sub-band, reconstruct at least one spectral coefficient of the sub-band; and

obtain a frequency domain audio signal according to the obtained at least one spectral coefficient of the current frame and the reconstructed at least one spectral coefficient of the sub-band.

14. The decoder according to claim 13, wherein when classify whether the sub-band is the bit allocation un-saturated sub-band or the bit allocation saturated sub-band, the processor being configured to execute the computer-executable instructions to:

compare the average quantity of allocated bits per spectral coefficient of the sub-band with a classification threshold; and

classify the sub-band as the bit allocation un-saturated sub-band when the average quantity of allocated bits per spectral coefficient of the sub-band is less than the classification threshold.

15. The decoder according to claim 14, wherein the average quantity of allocated bits per spectral coefficient of the sub-band is a ratio of a quantity of bits allocated for the sub-band to a quantity of spectral coefficients in the sub-band.

16. The decoder according to claim 14, wherein the processor being further configured to execute the computer-executable instructions to:

classify another sub-band of the current frame as a bit allocation saturated sub-band when an average quantity of allocated bits per spectral coefficient of the another sub-band is not less than the classification threshold.

17. The decoder according to claim 14, wherein the classification threshold is greater than 0.

18. The decoder according to claim 13, wherein the reconstructed at least one spectral coefficient of the sub-band had been filled with 0 when the bitstream is decoded.

19. The decoder according to claim 14, wherein the processor being further configured to execute the computer-executable instructions to:

classify another sub-band of the current frame as a bit allocation un-saturated sub-band, wherein each spectral coefficient of the another sub-band had been filled with 0 when the bitstream is decoded.

20. A decoder for decoding an audio signal, comprising:

a non-transitory memory for storing computer-executable instructions; and

a processor operatively coupled to the non-transitory memory, the processor being configured to execute the computer-executable instructions to;

decode a bitstream representing the audio signal to obtain at least one spectral coefficient of a current frame of the audio signal, wherein the current frame comprises a plurality of sub-bands;

calculate an average quantity of allocated bits per spectral coefficient of a sub-band of the current frame;

compare the average quantity of allocated bits per spectral coefficient of the sub-band with a classification threshold;

when the average quantity of allocated bits per spectral coefficient of the sub-band is less than the classification threshold, reconstruct at least one spectral coefficient of the sub-band; and

obtain a frequency domain audio signal according to the obtained at least one spectral coefficient of the current frame and the reconstructed at least one spectral coefficient of the sub-band.

21. The decoder according to claim 20, wherein the average quantity of allocated bits per spectral coefficient of the sub-band is a ratio of a quantity of bits allocated for the sub-band to a quantity of spectral coefficients in the sub-band.

22. The decoder according to claim 20, wherein the classification threshold is greater than 0.

23. The decoder according to claim 20, wherein the reconstructed at least one spectral coefficient of the sub-band had been filled with 0 when the bitstream is decoded.

24. The decoder according to claim 20, wherein the processor being further configured to execute the computer-executable instructions to:

when the average quantity of allocated bits per spectral coefficient of the sub-band is no less than the classification threshold, no reconstructing is performed on the sub-band.