Multi-lag format for audio coding

A method of decoding an audio signal from an encoded representation of the audio signal, the encoded representation including a spectral envelope of the audio signal and autocorrelation information for each of a plurality of subband audio signals generated from the audio signal, wherein the autocorrelation information for a given subband audio signal is based on an autocorrelation function of the subband audio signal, wherein the spectral envelope is determined at a first update rate and the autocorrelation information for the plurality of subband audio signals is determined at a second update rate, and wherein the first update rate is higher than the second update rate, the method comprising:

• receiving the encoded representation of the audio signal;
• extracting the spectral envelope and the autocorrelation information from the encoded representation of the audio signal;
• determining a reconstructed audio signal by spectral synthesis based on the spectral envelope and the autocorrelation information;
• and
• outputting the reconstructed audio signal;
• wherein the autocorrelation information for a given subband audio signal comprises an autocorrelation value for the subband audio signal and a lag value for the given subband audio signal.