Method and Apparatus for Decoding Speech/Audio Bitstream

Patent metadata

Field	Value
Publication number	US-2016343382-A1
Application number	US-201615197364-A
Country	US
Kind code	A1
Filing date	Jun 29, 2016
Priority date	Dec 31, 2013
Publication date	Nov 24, 2016
Grant date	—

Abstract

A method and an apparatus for decoding a speech/audio bitstream are disclosed, where the method for decoding a speech/audio bitstream includes determining whether a current frame is a normal decoding frame or a redundancy decoding frame, obtaining a decoded parameter of the current frame by means of parsing when the current frame is a normal decoding frame or a redundancy decoding frame, performing post-processing on the decoded parameter of the current frame to obtain a post-processed decoded parameter of the current frame, and using the post-processed decoded parameter of the current frame to reconstruct a speech/audio signal.

First claim

1 . A method for decoding a speech/audio bitstream, comprising:
determining whether a current frame is a normal decoding frame or a redundancy decoding frame; parsing a bitstream to obtain a decoded parameter of the current frame when the current frame is the normal decoding frame or the redundancy decoding frame; performing post-processing on the decoded parameter of the current frame to obtain a post-processed decoded parameter of the current frame; and setting the post-processed decoded parameter of the current frame to recover reconstruct a speech/audio signal.

2 . The method according to claim 1 , wherein the decoded parameter of the current frame comprises a spectral pair parameter of the current frame, and wherein performing the post-processing on the decoded parameter of the current frame comprises setting the spectral pair parameter of the current frame and a spectral pair parameter of a previous frame of the current frame to obtain a post-processed spectral pair parameter of the current frame.

3 . The method according to claim 2 , wherein the post-processed spectral pair parameter of the current frame is obtained through calculation using the formula lsp[k]=α*lsp_old[k]+δ*lsp_new[k], wherein 0≦k≦M, wherein lsp[k] is the post-processed spectral pair parameter of the current frame, wherein lsp_old[k] is the spectral pair parameter of the previous frame, wherein lsp_new[k] is the spectral pair parameter of the current frame, wherein M is an order of spectral pair parameters, wherein α is a weight of the spectral pair parameter of the previous frame, wherein δ is a weight of the spectral pair parameter of the current frame, wherein α≧0 , wherein δ≧0, and wherein α+δ=1.

4 . The method according to claim 2 , wherein the post-processed spectral pair parameter of the current frame is obtained through calculation using the formula lsp[k]=α*lsp_old[k]+β*lsp_mid[k]+δ*lsp_new[k], wherein 0≦k≦M, wherein lsp[k] is the post-processed spectral pair parameter of the current frame, wherein lsp_old[k] is the spectral pair parameter of the previous frame, wherein lsp_mid[k] is a middle value of the spectral pair parameter of the current frame, wherein lsp_new[k] is the spectral pair parameter of the current frame, wherein M is an order of spectral pair parameters, wherein α is a weight of the spectral pair parameter of the previous frame, wherein β is a weight of the middle value of the spectral pair parameter of the current frame, wherein δ is a weight of the spectral pair parameter of the current frame, wherein a α≧0, wherein β≧0, wherein δ≧0, and wherein α+β+δ=1.

5 . The method according to claim 4 , wherein when the current frame is the redundancy decoding frame and a signal class of the current frame is not unvoiced, and when a signal class of a next frame of the current frame is unvoiced, a value of β is 0 or is less than a preset threshold.

6 . The method according to claim 4 , wherein when the current frame is the redundancy decoding frame and a signal class of the current frame is not unvoiced, a spectral tilt factor of the previous frame of the current frame is less than a preset spectral tilt factor threshold, a value of β is 0 or is less than a preset threshold.

7 . The method according to claim 4 , wherein when the current frame is the redundancy decoding frame and a signal class of the current frame is not unvoiced, a signal class of a next frame of the current frame is unvoiced and a spectral tilt factor of the previous frame of the current frame is less than a preset spectral tilt factor threshold, a value of β is 0 or is less than a preset threshold.

8 . The method according to claim 3 , wherein when a signal class of the current frame is unvoiced, the previous frame of the current frame is the redundancy decoding frame, and a signal class of the previous frame of the current frame is not unvoiced, a value of α is 0 or is less than a preset threshold.

9 . The method according to claim 3 , wherein when the current frame is the redundancy decoding frame and a signal class of the current frame is not unvoiced, when a signal class of a next frame of the current frame is unvoiced, a value of δ is 0 or is less than a preset threshold.

10 . The method according to claim 3 , wherein when the current frame is the redundancy decoding frame and a signal class of the current frame is not unvoiced, a spectral tilt factor of the previous frame of the current frame is less than a preset spectral tilt factor threshold, a value of δ is 0 or is less than a preset threshold.

11 . The method according to claim 3 , wherein when the current frame is the redundancy decoding frame and a signal class of the current frame is not unvoiced, a signal class of a next frame of the current frame is unvoiced and a spectral tilt factor of the previous frame of the current frame is less than a preset spectral tilt factor threshold, a value of δ is 0 or is less than a preset threshold.

12 . The method according to claim 6 , wherein the spectral tilt factor may be positive or negative, and wherein a smaller spectral tilt factor indicates the signal class, which is more inclined to be unvoiced, of a frame corresponding to the spectral tilt factor.

13 . The method according to claim 1 , wherein the decoded parameter of the current frame comprises an adaptive codebook gain of the current frame, and wherein when the current frame is the redundancy decoding frame, when a next frame of the current frame is an unvoiced frame, or a next frame of the next frame of the current frame is the unvoiced frame and an algebraic codebook of a current subframe of the current frame is a first quantity of times an algebraic codebook of a previous subframe of the current subframe or an algebraic codebook of the previous frame of the current frame, performing the post-processing on the decoded parameter of the current frame comprises attenuating an adaptive codebook gain of the current subframe of the current frame.

14 . The method according to claim 1 , wherein the decoded parameter of the current frame comprises an adaptive codebook gain of the current frame, and wherein when the current frame or a previous frame of the current frame is the redundancy decoding frame, when a signal class of the current frame is generic and a signal class of a next frame of the current frame is voiced or a signal class of the previous frame of the current frame is generic and the signal class of the current frame is voiced, and an algebraic codebook of one subframe in the current frame is different from an algebraic codebook of a previous subframe of the one subframe by a second quantity of times or the algebraic codebook of one subframe in the current frame is different from the algebraic codebook of the previous frame of the current frame by the second quantity of times, performing post-processing on the decoded parameter of the current frame comprises adjusting an adaptive codebook gain of a current subframe of the current frame according to at least one of a ratio of an algebraic codebook of the current subframe of the current frame to an algebraic codebook of a neighboring subframe of the current subframe of the current frame, a ratio of the adaptive codebook gain of the current subframe of the current frame to an adaptive codebook gain of the neighboring subframe of the current subframe of the current frame, and a ratio of the algebraic codebook of the current subframe of the current frame to the algebraic codebook of the previous frame of the current frame.

15 . The method according to claim 1 , wherein the decoded parameter of the current frame comprises an algebraic codebook of the c

Assignees

• Huawei Tech Co Ltd

Inventors

• Liu Zexin
• Zhang Xingtao
• Miao Lei

Classifications

• G10L19/008

  Multichannel audio signal coding or decoding using interchannel correlation to reduce redundancy, e.g. joint-stereo, intensity-coding or matrixing · CPC title

• G10L19/005 Primary

  Correction of errors induced by the transmission channel, if related to the coding algorithm · CPC title

• G10L19/167 Primary

  Audio streaming, i.e. formatting and decoding of an encoded audio signal representation into a data stream for transmission or storage purposes · CPC title

• G10L2025/932

  Decision in previous or following frames · CPC title

• G10L19/06

  Determination or coding of the spectral characteristics, e.g. of the short-term prediction coefficients · CPC title