Preprocessing method, preprocessing apparatus and coding device

• US 8,831,961 B2
• Filed: 06/10/2013
• Issued: 09/09/2014
• Est. Priority Date: 03/13/2009
• 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: Miao, Lei, Qi, Fengyan, Xu, Jianfeng, Zhang, Dejun, Zhang, Qing
• Primary Examiner(s): Saint Cyr, Leonard
• Application Number:
  US13/914,206
• Publication Number:
  US 20130275141A1
• Time in Patent Office: 456 Days
• Field of Search: 704216-219, 704500-504
• US Class Current: 704/500
• 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 19/09 Long term prediction, i.e. removing periodical redundancies, e.g. by using adaptive codebook or pitch predictor
• CPC Class Codes: G10L 19/18 Vocoders using multiple modes
• CPC Class Codes: G10L 21/06 Transformation of speech into a non-audible representation, e.g. speech visualisation or speech processing for tactile aids G10L15/26 takes precedence

Abstract

The present disclosure relates to coding and decoding technologies, and discloses a preprocessing method, a preprocessing apparatus, and a coding device. The preprocessing method includes: obtaining characteristic information of a current frame signal; identifying whether the current frame signal requires no coding operation of removing LTC according to the characteristic information of the current frame signal and preset information; and if identifying that the current frame signal requires no coding operation of removing LTC, performing the coding operation of removing STC for the current frame signal; and if identifying that the current frame signal requires the coding operation of removing LTC, performing the coding operations of removing both LTC and STC for the current frame signal. Through the technical solution provided herein, the coding operation of removing LTC is performed for only part of the input frame signals.

Claims

1. A preprocessing method, comprising:

obtaining characteristic information of a current frame signal;

identifying whether the current frame signal requires no coding operation of removing Long Term Correlation (LTC) according to the characteristic information of the current frame signal and preset information; and

if the current frame signal requires no coding operation of removing the LTC, performing a coding operation of removing Short Term Correlation (STC) for the current frame signal;

if the current frame signal requires the coding operation of removing the LTC, performing coding operations of removing both the LTC and the STC for the current frame signal;

wherein the characteristic information of the current frame signal is a periodicity factor parameter of the current frame signal;

and wherein the identifying of whether the current frame signal requires no coding operation of removing LTC according to the characteristic information of the current frame signal and the preset information comprises;

judging whether the periodicity factor parameter is greater than a periodicity factor threshold; and

identifying that the current frame signal requires no coding operation of removing LTC if the periodicity factor parameter is less than or equal to the periodicity factor threshold.

2. The preprocessing method according to claim 1, wherein before identifying that the current frame signal requires no coding operation of removing LTC, the method further comprises:

judging whether several frame signals prior to the current frame signal comprise any Long Term Prediction (LTP) frame, wherein the number of the frame signals prior to the current frame signal corresponds to the frame length of the current frame signal; and

identifying that the current frame signal requires no coding operation of removing LTC if none of the several frame signals prior to the current frame signal comprises the LTP frame.

3. A preprocessing apparatus, comprising:

an obtaining unit, of a coding device, configured to obtain characteristic information of a current frame an identifying unit, configured to identify whether the current frame signal requires no coding operation of removing Long Term Correlation (LTC) according to the characteristic information of the current frame signal obtained by the obtaining unit and preset information; and

an operating unit, configured to perform coding operations of removing both the LTC and Short Term Correlation (STC) for the current frame signal if the identifying unit identifies that the current frame signal requires the coding operation of removing the LTC;

or perform the coding operation of removing the STC for the current frame signal if the identifying unit identifies that the current frame signal requires no coding operation of removing the LTC;

wherein the obtaining unit comprises a calculating unit which is configured to calculate an energy value or a periodicity factor parameter of the current frame signal;

wherein the identifying unit comprises;

a judging unit, configured to judge whether the periodicity factor parameter calculated out by the calculating unit is greater than a periodicity factor threshold; and

a processing unit, configured to identify that the current frame signal requires no coding operation of removing LTC if the judging unit identifies that the periodicity factor parameter is less than or equal to the periodicity factor threshold, and identify that the current frame signal requires the coding operation of removing LTC if the judging unit identifies that the periodicity factor parameter is greater than the periodicity factor threshold.

4. A coding device, comprising:

a preprocessing apparatus, configured to obtain characteristic information of a current frame signal;

identify whether the current frame signal requires no coding operation of removing Long Term Correlation (LTC) according to the characteristic information of the current frame signal and preset information;

perform a coding operation of removing Short Term Correlation (STC) for the current frame signal if the current frame signal requires no coding operation of removing the LTC, or perform coding operations of removing both the LTC and the STC for the current frame signal if the current frame signal requires the coding operation of removing the LTC; and

an entropy coding apparatus, configured to perform entropy coding for the current frame signal by using a result of each of the coding operation;

wherein, the preprocessing apparatus comprises;

an obtaining unit, configured to calculate a periodicity factor parameter of the current frame signal;

an identifying unit, configured to judge whether the periodicity factor parameter calculated out by the obtaining unit is greater than a periodicity factor threshold; and

an operating unit, configured to perform coding operations of removing both the LTC and STC for the current frame signal if the identifying unit identifies that the periodicity factor parameter is greater than the periodicity factor threshold, or perform the coding operation of removing STC for the current frame signal if the identifying unit identifies that the periodicity factor parameter is less than or equal to the periodicity factor threshold.