Patent ID: 11894007
Assignee: HUAWEI TECHNOLOGIES CO., LTD.
Field: Computer technology (Electrical engineering)
Classification: CPC G | IPC G

Claim 18:
19. The audio signal encoder of claim 18, wherein when executed by the one or more processors, the program instructions cause the audio signal encoder to be configured to:
calculate an energy ratio according to the following first equation:

Ratio=Energy1−Energy0,, wherein Ratio is the energy ratio, wherein Energy0 is a first maximum energy in decibel (dB) in a first frequency region [0, FMIN], wherein Energy1 is a second maximum energy in dB in a second frequency region [FMIN, 900], wherein FMIN is a predetermined minimum frequency in Hertz (Hz), and wherein 900 Hz is a predetermined maximum frequency;
adjust the energy ratio using an average normalized pitch correlation of the current frame to obtain an adjusted energy ratio according to the following second equation:

Ratio ⇐Ratio·Voicing,, wherein Voicing is the average normalized pitch correlation, wherein Ratio on a right side of the second equation is the energy ratio before being adjusted, and wherein Ratio on a left side of the second equation is the adjusted energy ratio;
calculate a smoothed energy ratio of the current frame using the adjusted energy ratio; and
determine that the current frame lacks low-frequency energy when the smoothed energy ratio is greater than a first threshold or the adjusted energy ratio is greater than a second threshold.