A converting portion converts each of blocks of an input digital audio signal into a number of spectral frequency-band components, the blocks being produced from the signal along a time axis. A bit-allocating portion allocates coding bits to each frequency band. A scalefactor is determined in accordance...http://www.google.com/patents/US6456963?utm_source=gb-gplus-sharePatent US6456963 - Block length decision based on tonality index
