METHOD OF AND DEVICE FOR ENCODING A HIGH FREQUENCY SIGNAL RELATING TO BANDWIDTH EXPANSION IN SPEECH AND AUDIO CODING

摘要

A method and a device for encoding a high frequency signal, and a method and a device for decoding a high frequency signal are provided, which relate to encoding and decoding technology. The method for encoding a high frequency signal includes: determining a signal class of a high frequency signal of a current frame; smoothing and scaling time envelopes of the high frequency signal of the current frame and obtaining time envelopes of the high frequency signal of the current frame that require to be encoded, if the high frequency signal of the current frame is a NON-TRANSIENT signal and a high frequency signal of the previous frame is a TRANSIENT signal; and quantizing and encoding the time envelopes of the high frequency signal of the current frame that require to be encoded, and frequency information and signal class information of the high frequency signal of the current frame. Signal class information of the TRANSIENT signal is used when the signal class information of the high frequency signal of the current frame is quantized and encoded. Therefore, the performance of the TRANSIENT signal is improved, and the deviation of the characteristics of a restored high frequency signal from the characteristics of an actual high frequency signal is reduced.