1. A method for generating a set of filter coefficients for an audio signal, comprising:obtaining a set of subband filter coefficients for each subband, wherein the set of subband filter coefficients is obtained from a set of time domain binaural room impulse response (BRIR) filter coefficients;
obtaining average reverberation time information of each subband by using a reverberation time extracted from the set of subband filter coefficients for a corresponding subband;
obtaining one or more coefficients for curve fitting the average reverberation time information;
obtaining flag information indicating whether a length of the set of time domain BRIR filter coefficients is larger than a predetermined value;
determining a filter order of each subband, wherein the filter order is determined, based at least in part on the flag information, by using the average reverberation time information or by using the coefficients for curve fitting, and wherein the filter order is determined to be variable in a frequency domain; and
truncating the set of subband filter coefficients by using the filter order of a corresponding subband.