Method and apparatus for processing lost frame

• US 9,852,738 B2
• Filed: 12/21/2016
• Issued: 12/26/2017
• Est. Priority Date: 06/25/2014
• 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: Wang, Bin, Liu, Zexin, Miao, Lei
• Primary Examiner(s): YEN, ERIC L
• Application Number:
  US15/385,881
• Publication Number:
  US 20170103764A1
• Time in Patent Office: 370 Days
• 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 19/083 the excitation function being an excitation gain G10L25/90 takes precedence
• CPC Class Codes: G10L 19/24 Variable rate codecs, e.g. for generating different qualities using a scalable representation such as hierarchical encoding or layered encoding
• CPC Class Codes: G10L 2025/932 Decision in previous or following frames
• CPC Class Codes: G10L 21/038 using band spreading techniques
• CPC Class Codes: G10L 21/0388 Details of processing therefor
• CPC Class Codes: G10L 25/93 Discriminating between voiced and unvoiced parts of speech signals G10L25/90 takes precedence

Abstract

Embodiments of the present application provide a method and an apparatus for recovering a lost frame in a received audio signal. The method for recovering a lost frame includes: determining an initial high-frequency band signal of a current lost frame; determining a gain of the current lost frame; determining gain adjustment information of the current lost frame; adjusting the gain of the current lost frame according to the gain adjustment information, to obtain an adjusted gain of the current lost frame; and adjusting the initial high-band signal according to the adjusted gain, to obtain a high-frequency band signal of the current lost frame. The method and the apparatus for recovering a lost frame provided in the embodiments of the present application can be used in an audio signal decoding process for low-loss recovery of a lost frame of the audio signal, resulting in improved performance of an audio signal decoder.

Claims

1. A method for recovering lost frames in a received audio signal, performed by a signal decoding apparatus in an audio signal receiver, wherein the method comprises:

determining an initial high-frequency band signal of a current lost frame in a received audio signal;

determining a gain of the current lost frame according to a gain of a previous frame of the current lost frame;

obtaining adjustment information of the current lost frame for adjusting the gain of the current lost frame;

obtaining an adjusted gain of the current lost frame by adjusting the gain of the current lost frame according to the adjustment information;

obtaining an adjusted excitation adjustment factor according to the adjustment information; and

adjusting the initial high-frequency band signal according to the adjusted gain and the adjusted excitation adjustment factor, to obtain the high-frequency band signal of the current lost frame;

wherein the adjustment information of the current lost frame comprises any one or any combination of;

class information of the current lost frame,

low-frequency band spectral tilt of the current lost frame, and

low-frequency band signal energy of the current lost frame.

2. The method according to claim 1, wherein the adjustment information comprises class information of the current lost frame, and low-frequency band signal energy of the current lost frame, and wherein the adjustment information further comprises a quantity of consecutive frames that are lost, including the current lost frame,

wherein obtaining an adjusted excitation adjustment factor according to the adjustment information comprises:

when the quantity of consecutive frames that are lost is 1, a high frequency excitation energy of the current lost frame is greater than a high frequency excitation energy of a previous frame of the current lost frame, the current lost frame is not in an unvoiced class, and a previous frame before the current lost frame is not in the unvoiced class, adjusting an initial excitation adjustment factor according to a low-frequency band signal energy of the previous frame of the current lost frame and the low-frequency band signal energy of the current lost frame, to obtain the adjusted excitation adjustment factor.

3. The method according to claim 1, wherein the adjustment information comprises class information of the current lost frame, and low-frequency band signal energy of the current lost frame, and wherein the adjustment information further comprises a quantity of consecutive frames that are lost, including the current lost frame,

wherein obtaining an adjusted excitation adjustment factor according to the adjustment information comprises:

when the quantity of consecutive frames that are lost is 1, a high frequency excitation energy of the current lost frame is less than half of a high frequency excitation energy of a previous frame of the current lost frame, a ratio of the low-frequency band signal energy of the current lost frame to a low-frequency band signal energy of the previous frame of the current lost frame is within a preset interval, and the previous frame of the current lost frame is in an unvoiced class, adjusting an initial excitation adjustment factor according to the low-frequency band signal energy of the previous frame of the current lost frame and the low-frequency band signal energy of the current lost frame, to obtain the adjusted excitation adjustment factor.

4. The method according to claim 1, wherein determining the initial high-frequency band signal of the current lost frame comprises:

estimating an encoding parameter of the current lost frame according to an encoding parameter of the previous frame of the current lost frame; and

recovering an initial high-frequency band signal of the current lost frame according to the encoding parameter of the current lost frame.

5. An audio signal decoding apparatus, comprising:

a processor, and a storage medium coupled to the processor and storing programming instructions for execution by the processor,

wherein the programming instructions, when executed by the processor, cause the processor to perform a process of recovering lost frames in a received audio signal,

wherein the process comprises;

determining an initial high-frequency band signal of a current lost frame;

determining a gain of the current lost frame according to a gain of a previous frame of the current lost frame;

obtaining adjustment information of the current lost frame for adjusting the gain of the current lost frame;

obtaining an adjusted gain of the current lost frame by adjusting the gain of the current lost frame according to the adjustment information;

obtaining an adjusted excitation adjustment factor according to the adjustment information; and

adjusting the initial high-frequency band signal according to the adjusted gain and the adjusted excitation adjustment factor, to obtain the high-frequency band signal of the current lost frame;

wherein the adjustment information of the current lost frame comprises any one or any combination of;

class information of the current lost frame,

low-frequency band spectral tilt of the current lost frame, and

low-frequency band energy of the current lost frame.

6. The apparatus according to claim 5, wherein the adjustment information comprises class information of the current lost frame, and low-frequency band signal energy of the current lost frame, and wherein the adjustment information further comprises a quantity of consecutive frames that are lost, including the current lost frame,

wherein obtaining an adjusted excitation adjustment factor according to the adjustment information comprises:

when the quantity of consecutive lost frames is 1, a high frequency excitation energy of the current lost frame is greater than a high frequency excitation energy of a previous frame of the current lost frame, the current lost frame is not in an unvoiced class, and a previous frame before the current lost frame is not in the unvoiced class, adjusting an initial excitation adjustment factor according to the low-frequency band signal energy of the previous frame of the current lost frame and the low-frequency band signal energy of the current lost frame, to obtain the adjusted excitation adjustment factor.

7. The apparatus according to claim 5, wherein the adjustment information comprises class information of the current lost frame, and low-frequency band signal energy of the current lost frame, and wherein the adjustment information further comprises a quantity of consecutive frames that are lost, including the current lost frame,

wherein obtaining an adjusted excitation adjustment factor according to the adjustment information comprises:

when the quantity of consecutive frames that are lost is 1, a high frequency excitation energy of the current lost frame is less than half of a high frequency excitation energy of a previous frame of the current lost frame, a ratio of a low-frequency band signal energy of the current lost frame to a low-frequency band signal energy of the previous frame of the current lost frame is within a preset interval, and the previous frame of the current lost frame is in an unvoiced class, adjusting an initial excitation adjustment factor according to the low-frequency band signal energy of the previous frame of the current lost frame and the low-frequency band signal energy of the current lost frame, to obtain the adjusted excitation adjustment factor.

8. The apparatus according to claim 5, wherein determining the initial high-frequency band signal of the current lost frame comprises:

estimating an encoding parameter of the current lost frame according to an encoding parameter of the previous frame of the current lost frame; and

recovering an initial high-frequency band signal of the current lost frame according to the encoding parameter of the current lost frame.