[57] A method of reproducing multichannel audio, comprising: receiving a bitstream including a plurality of discrete front audio channels that carry at least left, right and center front audio signals and discrete left and right surround-sound audio channels that carry a mix of left, right and center surround-sound audio signals in a predetermined discrete multichannel audio format and a discrete surround-sound extension channel that carries the center surround-sound audio signal as extension bits appended to said predetermined discrete multichannel audio format; reading out the bits in the predetermined discrete multichannel audio format; decoding the bits in the predetermined discrete multichannel audio format to reproduce said discrete front audio channels and said discrete left and right surround-sound audio channels; reading out the extension bits; decoding the extension bits to provide the discrete surround-sound extension channel; mix decoding the discrete left and right surround-sound audio channels using the surround-sound extension channel to provide discrete left, right and center surround-sound audio channels that carry the left, right and center surround-sound audio signals, respectively; applying the discrete front audio channels and the discrete left, right and center surround-sound audio channels to respective speaker channels to reproduce the front audio signals and discrete left, right and center surround-sound audio signals.
