The effective (or logical) size of the encoder buffer in a video transmission system is varied with the transmission bit-rate. Also, a minimum fill level is maintained in the encoder buffer whenever the transmission rate is too high to assure otherwise that the decoder buffer will not overflow or underflow....http://www.google.de/patents/US5566208?utm_source=gb-gplus-sharePatent US5566208 - Encoder buffer having an effective size which varies automatically with the channel bit-rate
