1. A method of encoding an audio signal, the method comprising: generating at least one audio data frame having at least one channel, wherein each channel is divided into a plurality of blocks; selecting a sub-block partitioning scheme; selecting a number of sub-blocks into which the block is to be partitioned, the selected number of sub-blocks being chosen from numbers of sub-blocks available for the selected sub-block partitioning scheme; partitioning the block of audio data into sub-blocks according to the selected number of sub-blocks; and coding the partitioned sub-blocks according to a selected entropy coding scheme.