Encoding and decoding methods, and encoding and decoding apparatuses for stereo signal

An encoding method for a stereo audio signal, comprising:

• determining an inter-channel time difference in a current frame;
• performing interpolation processing based on the inter-channel time difference in the current frame and an inter-channel time difference in a previous frame of the current frame, to obtain an inter-channel time difference after the interpolation processing;
• performing delay alignment on a stereo audio signal in the current frame based on the inter-channel time difference in the current frame, to obtain a stereo audio signal after the delay alignment;
• performing time-domain downmixing processing on the stereo audio signal after the delay alignment, to obtain a primary-channel signal and a secondary-channel signal in the current frame;
• quantizing the inter-channel time difference after the interpolation processing, and writing the quantized inter-channel time difference into a bitstream;
• and
• quantizing the primary-channel signal and the secondary-channel signal in the current frame, and writing the quantized primary-channel signal and the quantized secondary-channel signal into the bitstream;
• wherein the inter-channel time difference after the interpolation processing is calculated according to a formula A=(1−β)·B+β·C, wherein
• A is the inter-channel time difference after the interpolation processing, B is the inter-channel time difference in the current frame, C is the inter-channel time difference in the previous frame of the current frame, β is a second interpolation coefficient, and 0<β<1;
• wherein the second interpolation coefficient β is directly proportional to an encoding and decoding delay, and is inversely proportional to a frame length of the current frame, wherein the encoding and decoding delay comprises an encoding delay in a process of encoding, by an encoding end, the primary-channel signal and the secondary-channel signal that are obtained after the time-domain downmixing processing, and a decoding delay in a process of decoding, by a decoding end, the bitstream to obtain a primary-channel signal and a secondary-channel signal.

An encoding apparatus, comprising:

• at least one processor;
• and
• one or more memories coupled to the at least one processor and storing programming instructions for execution by the at least one processor to:
• determine an inter-channel time difference in a current frame;
• perform interpolation processing based on the inter-channel time difference in the current frame and an inter-channel time difference in a previous frame of the current frame, to obtain an inter-channel time difference after the interpolation processing;
• perform delay alignment on a stereo audio signal in the current frame based on the inter-channel time difference in the current frame, to obtain a stereo audio signal after the delay alignment;
• perform time-domain downmixing processing on the stereo audio signal after the delay alignment, to obtain a primary-channel signal and a secondary-channel signal;
• and
• quantize the inter-channel time difference after the interpolation processing, and write the quantized inter-channel time difference into a bitstream;
• and quantize the primary-channel signal and the secondary-channel signal, and write the quantized primary-channel signal and the quantized secondary-channel signal into the bitstream;
• wherein the inter-channel time difference after the interpolation processing is calculated according to a formula A=α·B+(1−α)·C, wherein
• A is the inter-channel time difference after the interpolation processing, B is the inter-channel time difference in the current frame, C is the inter-channel time difference in the previous frame of the current frame, a is a first interpolation coefficient, and 0<α<1;
• wherein the first interpolation coefficient α is inversely proportional to an encoding and decoding delay, and is directly proportional to a frame length of the current frame, wherein the encoding and decoding delay comprises an encoding delay in a process of encoding, by an encoding end, the primary-channel signal and the secondary-channel signal that are obtained after the time-domain downmixing processing, and a decoding delay in a process of decoding, by a decoding end, the bitstream to obtain a primary-channel signal and a secondary-channel signal.

An encoding apparatus, comprising:

• at least one processor;
• and
• one or more memories coupled to the at least one processor and storing programming instructions for execution by the at least one processor to:
• determine an inter-channel time difference in a current frame;
• perform interpolation processing based on the inter-channel time difference in the current frame and an inter-channel time difference in a previous frame of the current frame, to obtain an inter-channel time difference after the interpolation processing;
• perform delay alignment on a stereo audio signal in the current frame based on the inter-channel time difference in the current frame, to obtain a stereo audio signal after the delay alignment;
• perform time-domain downmixing processing on the stereo audio signal after the delay alignment, to obtain a primary-channel signal and a secondary-channel signal;
• and
• quantize the inter-channel time difference after the interpolation processing, and write the quantized inter-channel time difference into a bitstream;
• and quantize the primary-channel signal and the secondary-channel signal, and write the quantized primary-channel signal and the quantized secondary-channel signal into the bitstream;
• wherein the inter-channel time difference after the interpolation processing in the current frame is calculated according to a formula A=(1−β)·B+β·C, wherein
• A is the inter-channel time difference after the interpolation processing, B is the inter-channel time difference in the current frame, C is the inter-channel time difference in the previous frame of the current frame, β is a second interpolation coefficient, and 0<β<1;
• wherein the second interpolation coefficient β is directly proportional to an encoding and decoding delay, and is inversely proportional to a frame length of the current frame, wherein the encoding and decoding delay comprises an encoding delay in a process of encoding, by an encoding end, the primary-channel signal and the secondary-channel signal that are obtained after the time-domain downmixing processing, and a decoding delay in a process of decoding, by a decoding end, the bitstream to obtain a primary-channel signal and a secondary-channel signal.

A non-transitory computer-readable storage medium storing computer instructions, that when executed by one or more processors, cause the one or more processors to perform operations comprising:

• determining an inter-channel time difference in a current frame;
• performing interpolation processing based on the inter-channel time difference in the current frame and an inter-channel time difference in a previous frame of the current frame, to obtain an inter-channel time difference after the interpolation processing;
• performing delay alignment on a stereo audio signal in the current frame based on the inter-channel time difference in the current frame, to obtain a stereo audio signal after the delay alignment;
• performing time-domain downmixing processing on the stereo audio signal after the delay alignment, to obtain a primary-channel signal and a secondary-channel signal in the current frame;
• quantizing the inter-channel time difference after the interpolation processing, and writing the quantized inter-channel time difference into a bitstream;
• and
• quantizing the primary-channel signal and the secondary-channel signal in the current frame, and writing the quantized primary-channel signal and the quantized secondary-channel signal into the bitstream;
• wherein the inter-channel time difference after the interpolation processing is calculated according to a formula A=α·B+(1−α)·C, wherein
• A is the inter-channel time difference after the interpolation processing, B is the inter-channel time difference in the current frame, C is the inter-channel time difference in the previous frame of the current frame, a is a first interpolation coefficient, and 0<α<1;
• wherein the first interpolation coefficient α is inversely proportional to an encoding and decoding delay, and is directly proportional to a frame length of the current frame, wherein the encoding and decoding delay comprises an encoding delay in a process of encoding, by an encoding end, the primary-channel signal and the secondary-channel signal that are obtained after the time-domain downmixing processing, and a decoding delay in a process of decoding, by a decoding end, the bitstream to obtain a primary-channel signal and a secondary-channel signal.

A non-transitory computer-readable storage medium storing computer instructions, that when executed by one or more processors, cause the one or more processors to perform operations comprising:

• determining an inter-channel time difference in a current frame;
• performing interpolation processing based on the inter-channel time difference in the current frame and an inter-channel time difference in a previous frame of the current frame, to obtain an inter-channel time difference after the interpolation processing;
• performing delay alignment on a stereo audio signal in the current frame based on the inter-channel time difference in the current frame, to obtain a stereo audio signal after the delay alignment;
• performing time-domain downmixing processing on the stereo audio signal after the delay alignment, to obtain a primary-channel signal and a secondary-channel signal in the current frame;
• quantizing the inter-channel time difference after the interpolation processing, and writing the quantized inter-channel time difference into a bitstream;
• and
• quantizing the primary-channel signal and the secondary-channel signal in the current frame, and writing the quantized primary-channel signal and the quantized secondary-channel signal into the bitstream;
• wherein the inter-channel time difference after the interpolation processing in the current frame is calculated according to a formula A=(1−β)·B+β·C, wherein
• A is the inter-channel time difference after the interpolation processing, B is the inter-channel time difference in the current frame, C is the inter-channel time difference in the previous frame of the current frame, β is a second interpolation coefficient, and 0<β<1;
• wherein the second interpolation coefficient β is directly proportional to an encoding and decoding delay, and is inversely proportional to a frame length of the current frame, wherein the encoding and decoding delay comprises an encoding delay in a process of encoding, by an encoding end, the primary-channel signal and the secondary-channel signal that are obtained after the time-domain downmixing processing, and a decoding delay in a process of decoding, by a decoding end, the bitstream to obtain a primary-channel signal and a secondary-channel signal.