Signal encoding and decoding methods and devices

A signal decoding method, comprising:

• determining, according to a quantity of available bits and a first saturation threshold i, a quantity k of subbands to be decoded, wherein i is a positive number, and k is a positive integer;
• selecting, according to decoded envelopes of all subbands, k subbands from all the subbands, or selecting k subbands from all the subbands according to a psychoacoustic model;
• and
• performing a first-time decoding operation, to obtain quantized spectral coefficients of the k subbands.

A signal encoding device, comprising:

• a determining unit, configured to determine, according to a quantity of available bits and a first saturation threshold i, a quantity k of subbands to be encoded, wherein i is a positive number and k is a positive integer;
• a selecting unit, configured to select, according to the quantity k of subbands that is determined by the determining unit, k subbands from all the subbands, or select k subbands from all the subbands according to a psychoacoustic model;
• and
• an encoding unit, configured to perform a first-time encoding operation on spectral coefficients of the k subbands selected by the selecting unit.

A signal decoding device, comprising:

• a first determining unit, configured to determine, according to a quantity of available bits and a first saturation threshold i, a quantity k of subbands to be decoded, wherein i is a positive number, and k is a positive integer;
• a selecting unit, configured to:
• according to the quantity k of subbands that is determined by the first determining unit, select, according to decoded envelopes of all subbands, k subbands from all the subbands, or select k subbands from all the subbands according to a psychoacoustic model;
• and
• a decoding unit, configured to perform a first-time decoding operation, to obtain quantized spectral coefficients of the k subbands selected by the selecting unit.