Audio signal encoding method and mobile phone

An audio signal encoding method, comprising:

• obtaining, by a mobile phone, a digital audio signal in time domain;
• transforming, by the mobile phone, the digital audio signal in time domain to an audio signal in frequency domain, wherein the audio signal in frequency domain comprises a current frame, and the current frame comprises a subband i, a subband j, a subband x and a subband y;
• obtaining, by the mobile phone, an average energy of the subband i, an average energy of the subband j, a spectral peak of the subband x, a spectral average of the subband x, a spectral peak of the subband v, and a spectral average of the subband y;
• encoding, by the mobile phone and using a high quality transform coding (HQ) algorithm, the current frame to obtain an encoded audio signal when:
• a product of the spectral peak of the subband x multiplied by the spectral average of the subband y is less than a product of the spectral peak of the subband y multiplied by the spectral average of the subband x multiplied by a first constant (T44), and the spectral peak of the subband y is greater than a product of the spectral average of the subband y multiplied by a second constant (T45);
• or
• the product of the spectral peak of the subband x multiplied by the spectral average of the subband y is greater than a product of the spectral peak of the subband y multiplied by the spectral average of the subband x multiplied by a third constant (T46), and the spectral peak of the subband y is less than a product of the spectral average of the subband y multiplied by the T45;
• and
• transmitting, by the mobile phone, the encoded audio signal via a network.

A mobile phone, comprising:

• a hardware circuit, configured to obtain a digital audio signal in time domain;
• a memory storing program instructions;
• and
• at least one processor coupled to the memory, wherein the program instructions cause the at least one processor to be configured to:
• transform the digital audio signal in time domain to an audio signal in frequency domain, wherein the audio signal in frequency domain comprises a current frame, and the current frame comprises a subband i, a subband j, a subband x and a subband y;
• obtain an average energy of the subband i, an average energy of the subband j, a spectral peak of the subband x, a spectral average of the subband x, a spectral peak of the subband y, and a spectral average of the subband y;
• and
• encode, using a high quality transform coding (HQ) algorithm, the current frame to obtain an encoded audio signal when the average energy of the subband j is greater than a product of the average energy of the subband i multiplied by a first constant (T4), a product of the spectral peak of the subband x multiplied by the spectral average of the subband y is greater than a product of the spectral peak of the subband y multiplied by the spectral average of the subband x and multiplied by a lowest value of a first interval (R1), and the product of the spectral peak of the subband x multiplied by the spectral average of the subband y is less than a product of the spectral peak of the subband y multiplied by the spectral average of the subband x and multiplied by a highest value of the R1;
• and
• a network interface, configured to transmit the encoded audio signal via a network.

A mobile phone, comprising:

• a hardware circuit, configured to obtain a digital audio signal in time domain;
• a memory storing program instructions;
• and
• at least one processor coupled to the memory, wherein the program instructions cause the at least one processor to be configured to:
• transform the digital audio signal in time domain to an audio signal in frequency domain, wherein the audio signal in frequency domain comprises a current frame, and the current frame comprises a subband i, a subband j, a subband x and a subband y;
• obtain an average energy of the subband i, an average energy of the subband j, a spectral peak of the subband x, a spectral average of the subband x, a spectral peak of the subband y, and a spectral average of the subband y;
• and
• encode, using a high quality transform coding (HQ) algorithm, the current frame to obtain an encoded audio signal when:
• a product of the spectral peak of the subband x multiplied by the spectral average of the subband y is less than a product of the spectral peak of the subband y multiplied by the spectral average of the subband x multiplied by a first constant (T44), and the spectral peak of the subband y is greater than a product of the spectral average of the subband y multiplied by a second constant (T45);
• or
• the product of the spectral peak of the subband x multiplied by the spectral average of the subband y is greater than a product of the spectral peak of the subband y multiplied by the spectral average of the subband x multiplied by a third constant (T46), and the spectral peak of the subband y is less than a product of the spectral average of the subband y multiplied by the T45;
• and
• a network interface, configured to transmit the encoded audio signal via a network.

An audio signal encoding method, comprising:

• obtaining, by a mobile phone, an analog audio signal;
• converting, by the mobile phone, the analog audio signal into a digital audio signal in time domain;
• transforming, by the mobile phone, the digital audio signal in time domain to an audio signal in frequency domain, wherein the audio signal in frequency domain comprises a current frame, and the current frame comprises a plurality of subbands;
• obtaining, by the mobile phone, reference parameters of the plurality of subbands;
• encoding, by the mobile phone and using a high quality transform coding (HQ) algorithm, the current frame to obtain an encoded audio signal when the reference parameters meet a preset parameter condition;
• and
• transmitting, by the mobile phone, the encoded audio signal via a network;
• wherein:
• the current frame comprises a subband x and a subband y;
• wherein the reference parameters comprise a spectral peak of the subband x, a spectral average of the subband x, a spectral peak of the subband y, and a spectral average of the subband y;
• wherein the preset parameter condition comprises:
• a product of the spectral peak of the subband x multiplied by the spectral average of the subband y is less than a product of the spectral peak of the subband y multiplied by the spectral average of the subband x multiplied by a first constant (T44), and the spectral peak of the subband y is greater than a product of the spectral average of the subband y multiplied by a second constant (T45);
• or
• the product of the spectral peak of the subband x multiplied by the spectral average of the subband y is greater than a product of the spectral peak of the subband y multiplied by the spectral average of the subband x multiplied by a third constant (T46), and the spectral peak of the subband y is less than a product of the spectral average of the subband y multiplied by the T45.

An audio signal encoder, comprising:

• at least one microphone, configured to obtain an analog audio signal;
• an analog-digital convertor coupled to the at least one microphone, configured to convert the analog audio signal into a digital audio signal in time domain;
• a memory storing program instructions;
• and
• at least one processor coupled to the memory, wherein the program instructions cause the at least one processor to be configured to:
• transform the digital audio signal in time domain to an audio signal in frequency domain, wherein the audio signal in frequency domain comprises a current frame, and the current frame comprises a plurality of subbands;
• obtain reference parameters of the plurality of subbands;
• and
• encode, using a high quality transform coding (HQ) algorithm, the current frame to obtain an encoded audio signal when the reference parameters meet a preset parameter condition;
• and
• a network interface, configured to transmit the encoded audio signal via a network;
• wherein the current frame comprises a subband x and a subband y;
• wherein the reference parameters comprise a spectral peak of the subband x, a spectral average of the subband x, a spectral peak of the subband y, and a spectral average of the subband y;
• wherein the preset parameter condition comprises:
• a product of the spectral peak of the subband x multiplied by the spectral average of the subband y is less than a product of the spectral peak of the subband y multiplied by the spectral average of the subband x multiplied by a first constant (T44), and the spectral peak of the subband y is greater than a product of the spectral average of the subband y multiplied by a second constant (T45);
• or
• the product of the spectral peak of the subband x multiplied by the spectral average of the subband y is greater than a product of the spectral peak of the subband y multiplied by the spectral average of the subband x multiplied by a third constant (T46), and the spectral peak of the subband y is less than a product of the spectral average of the subband y multiplied by the T45.