Patent ID: 7761303

Claim:
A method of decoding an audio signal performed by an audio coding system, comprising: receiving an audio signal including at least one frame, the frame comprising at least one time slot and at least one parameter set; determining whether a Low Frequency Enhancement (LFE) mode is selected, the LFE mode being different from a normal mode for an LFE channel; extracting time slot information in variable bit length, the time slot information indicating a time slot to which a parameter set is applied; extracting LFE parameter band information in fixed bit length, the LFE parameter band information indicating a number of parameter bands for the LFE channel; and decoding the audio signal by applying the parameter of the parameter set to a parameter band of the time slot, based on the LFE parameter band information and the time slot information, wherein the process of extracting the time slot information comprises: extracting a number of time slots and a number of parameter sets from the audio signal to identify the time slot information; determining a bit length of the time slot information, the bit length being variable according to the number of time slots and the number of parameter sets; and extracting the time slot information based on the bit length, wherein a number of time slot information is equal to the number of parameter sets.