Method and apparatus for encoding or decoding an audio signal that is processed using multiple subbands and overlapping window functions

In MPEG-1 Audio Layer 3 following the 'window_switching_flag', the corresponding 2-bit value of 'block_type' is sent repeatedly although the decoder knows already from the occurrence of the parameter 'window_switching_flag' that a sequence of 'start block', 'short windows', 'stop block' and 'long window' will follow. Therefore transmitting the changing parameter 'block_type' several times is redundant information. According to the invention the superfluous parameter 'block_type' flag is not sent for block type signalling purposes. Instead, the two corresponding bits are used for signalling to the decoder differing subband signal window switching configuration types. These configuration types define in which of the total number of subbands used the window switching is affected, or not affected, by above parameter 'window_switching_flag'. These configuration types can further define different subbands groups fixed or variable within the total number of subbands, that are affected by the parameter 'window_switching_flag'.