SPEECH/AUDIO BITSTREAM DECODING METHOD AND APPARATUS

• US 20160372122A1
• Filed: 09/02/2016
• Published: 12/22/2016
• Est. Priority Date: 03/21/2014
• 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: Zhang, Xingtao, Liu, Zexin, Miao, Lei
• Granted Patent: US 10,269,357 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G10L 19/005 Correction of errors induced by the transmission channel, if related to the coding algorithm
• CPC Class Codes: G10L 19/06 Determination or coding of the spectral characteristics, e.g. of the short-term prediction coefficients
• CPC Class Codes: G10L 19/167 Audio streaming, i.e. formatting and decoding of an encoded audio signal representation into a data stream for transmission or storage purposes
• CPC Class Codes: G10L 19/26 Pre-filtering or post-filtering
• CPC Class Codes: G10L 2019/0002 Codebook adaptations

Abstract

The present invention disclose a speech/audio bitstream decoding method including: acquiring a speech/audio decoding parameter of a current speech/audio frame, where the foregoing current speech/audio frame is a redundant decoded frame or a speech/audio frame previous to the foregoing current speech/audio frame is a redundant decoded frame; performing post processing on the acquired speech/audio decoding parameter according to speech/audio parameters of X speech/audio frames, where the foregoing X speech/audio frames include M speech/audio frames previous to the foregoing current speech/audio frame and/or N speech/audio frames next to the foregoing current speech/audio frame; and recovering a speech/audio signal by using the post-processed speech/audio decoding parameter of the foregoing current speech/audio frame. The technical solutions of the present invention help improve quality of an output speech/audio signal.

Claims

1. A speech/audio bitstream decoding method, comprising:

acquiring a decoding parameter of a current frame, wherein the current frame is a redundant decoded frame or a frame previous to the current frame is a redundant decoded frame;

performing post processing on the decoding parameter of the current frame according to parameters of X frames, to obtain a post-processed decoding parameter of the current frame, wherein the X frames comprise M frames previous to the current frame and/or N frames next to the current frame, and wherein M and N are positive integers; and

recovering a signal of the current frame by using the post-processed decoding parameter of the current frame.

2. The method according to claim 1, wherein the decoding parameter of the current frame comprises a spectral pair parameter of the current frame, and wherein the performing post processing comprises:

performing post processing on the spectral pair parameter of the current frame according to at least one of a signal class, a spectrum tilt factor, an adaptive codebook gain, or a spectral pair parameter of the X frames, to obtain a post-processed spectral pair parameter of the current frame.

3. The method according to claim 1, wherein

the decoding parameter of the current frame comprises an adaptive codebook gain of the current frame, and the performing post processing comprises:

performing post processing on the adaptive codebook gain of the current frame according to at least one of a signal class, an algebraic codebook gain, or an adaptive codebook gain of the X frames, to obtain a post-processed adaptive codebook gain of the current frame.

4. The method according to claim 3, wherein a particular frame previous to the current frame is a redundant decoded frame, wherein the performing post processing on the adaptive codebook gain comprises:

attenuating an adaptive codebook gain of a current subframe of the current frame when the current frame is a redundant decoded frame, a signal class of the current frame is not unvoiced, a signal class of at least one of two frames next to the current frame is unvoiced, and an algebraic codebook gain of the current subframe of the current frame is greater than or equal to an algebraic codebook gain of the particular frame previous to the current frame.

5. The method according to claim 4, wherein:

the current frame is a redundant decoded frame, wherein the signal class of the current frame is not unvoiced, wherein the signal class of at least one of two frames next to the current frame is unvoiced, and wherein the algebraic codebook gain of the current subframe of the current frame is greater than or equal to an algebraic codebook gain of a subframe previous to the current subframe, and wherein the method further comprises;

attenuating an adaptive codebook gain of the current subframe.

6. The method according to claim 1, wherein the decoding parameter of the current frame comprises an algebraic codebook of the current frame, and wherein the performing post processing on the decoding parameter comprises:

performing post processing on the algebraic codebook of the current frame according to at least one of a signal class, an algebraic codebook, or a spectrum tilt factor of the X frames, to obtain a post-processed algebraic codebook of the current frame.

7. The method according to claim 1, wherein the decoding parameter of the current frame comprises a bandwidth extension envelope of the current frame, and wherein the performing post processing on the decoding parameter of the current frame comprises:

performing post processing on the bandwidth extension envelope of the current frame according to at least one of a signal class, a bandwidth extension envelope, or a spectrum tilt factor of the X speech/audio frames, to obtain a post-processed bandwidth extension envelope of the current frame.

8. The method according to claim 7, wherein the performing post processing on the bandwidth extension envelope of the current frame,

wherein the frame previous to the current frame is a normal decoded frame, wherein a signal class of the frame previous to the current frame is the same as that of a frame next to the current frame, and wherein the performing post processing on the bandwidth extension envelope of the current frame comprises:

obtaining the post-processed bandwidth extension envelope of the current frame based on a bandwidth extension envelope of the frame previous to the current frame and the bandwidth extension envelope of the current frame.

9. The method according to claim 8, wherein

the current frame is a prediction form of redundancy decoding, the method further comprising:

obtaining the post-processed bandwidth extension envelope of the current frame based on the bandwidth extension envelope of the frame previous to the current frame and the bandwidth extension envelope of the current frame.

10. The method according to claim 8, wherein

a signal class of the current frame is not unvoiced, a signal class of the frame next to the current frame is unvoiced, and a spectrum tilt factor of the frame previous to the current frame is less than or equal to a tenth threshold, the method further comprising:

modifying the bandwidth extension envelope of the current frame according to the bandwidth extension envelope or the spectrum tilt factor of the frame previous to the current frame, to obtain the post-processed bandwidth extension envelope of the current frame.

11. The method according to claim 8, wherein a modification factor for modifying the bandwidth extension envelope of the current frame is inversely proportional to the spectrum tilt factor of the frame previous to the current frame, and is proportional to a ratio of the bandwidth extension envelope of the frame previous to the current frame to the bandwidth extension envelope of the current frame.

12. The method according claim 1, wherein the decoding parameter of the current frame comprises a pitch period of the current frame, and wherein the performing post processing on the decoding parameter of the current frame comprises:

performing post processing on the pitch period of the current frame according to the signal classes and/or pitch periods of the X speech/audio frames, to obtain a post-processed pitch period of the current frame.

13. A decoder for decoding a speech/audio bitstream, comprising:

a memory storing instructions, and a processor coupled to the memory executes the instructions to;

acquire a decoding parameter of a current frame, wherein the current frame is a redundant decoded frame or a frame previous to the current frame is a redundant decoded frame;

perform post processing on the decoding parameter of the current frame according to speech/audio parameters of X frames, to obtain a post-processed decoding parameter of the current frame, wherein the X frames comprise M frames previous to the current frame and/or N frames next to the current frame, and wherein M and N are positive integers; and

recover a signal of the current frame by using the post-processed decoding parameter of the current frame.

14. The decoder according to claim 13, wherein the decoding parameter of the current frame comprises a spectral pair parameter of the current frame;

and

wherein the processor is configured to;

perform post processing on the spectral pair parameter of the current frame according to at least one of a spectral pair parameter, an adaptive codebook gain, a spectrum tilt factor, or a signal class of the X frames, to obtain a post-processed spectral pair parameter of the current frame.

15. The decoder according to claim 13, wherein the decoding parameter of the current frame comprises an adaptive codebook gain of the current frame;

the processor is configured to;

perform post processing on the adaptive codebook gain of the current frame according to at least one of a signal class, an algebraic codebook gain, or an adaptive codebook gain of the X frames, to obtain a post-processed adaptive codebook gain of the current frame.

16. The decoder according to claim 13, wherein the decoding parameter of the current frame comprises a bandwidth extension envelope of the current frame, and the processor is configured to:

perform post processing on the bandwidth extension envelope of the current frame according to at least one of a signal class, a bandwidth extension envelope, or a spectrum tilt factor of the X frames, to obtain a post-processed bandwidth extension envelope of the current frame.

17. The decoder according to claim 13, wherein the processor is configured to:

when the frame previous to the current frame is a normal decoded frame, and the signal class of the frame previous to the current frame is the same as that of the frame next to the current frame, obtain the post-processed bandwidth extension envelope of the current frame based on a bandwidth extension envelope of the frame previous to the current frame and the bandwidth extension envelope of the current frame.

18. The decoder according to claim 17, wherein the processor is further configured to

when the current frame is a prediction form of redundancy decoding, obtain the post-processed bandwidth extension envelope of the current frame based on a bandwidth extension envelope of the frame previous to the current frame and the bandwidth extension envelope of the current frame.

19. The decoder according to claim 17, wherein a modification factor used by the processor for modifying the bandwidth extension envelope of the current frame is inversely proportional to the spectrum tilt factor of the frame previous to the current frame, and is proportional to a ratio of the bandwidth extension envelope of the frame previous to the current frame to the bandwidth extension envelope of the current frame.

20. The decoder according to claim 13, wherein the decoding parameter of the current frame comprises a pitch period of the current frame, and the processor is specifically configured to:

perform post processing on the pitch period of the current frame according to at least one of the signal class or a pitch period of the X frames, to obtain a post-processed pitch period of the current frame.