Patent ID: 7783494

Claim:
A method of decoding an audio signal performed by an audio coding system, the audio signal including at least one frame, the frame comprising at least one time slot and at least one parameter set, comprising: extracting a number of time slots and a number of parameter sets from the audio signal to identify time slot information, the time slot information indicating a time slot to which a parameter set is applied; determining a bit length of time slot information, the bit length being variable according to the number of time slots, the number of parameter sets and previous time slot information associated with a previous parameter set; extracting the time slot information based on the bit length; and decoding the audio signal by applying the parameter set to the time slot corresponding to the time slot information, wherein the number of time slot information is equal to the number of parameter sets and the time slot information includes an absolute value for indicating a time slot to which a first parameter set is applied or a difference value for indicating a time slot to which a following parameter set of the first parameter set is applied, and wherein the absolute value is determined within a first maximum range, the first maximum range being calculated using the number of parameter sets and the number of time slots, and wherein the difference value is determined within a second maximum range, the second maximum range being calculated according to the previous time slot information.