has to be less than some specified maximum in order to prevent decoder buffer overflow and underflow this requirement is illustrated by the following example consider the case in which all the activity in a picture corresponds exactly to only those stripes coded by sub coder i in this case the i sub buffer would be full and the remaining sub buffers all empty in such a case albeit an unlikely one equivalence to a system with only one coding path and buffer store would only be achieved if each sub buffer was as large as the buffer in the single buffer coder of course the above example is extreme the optimum size of the sub buffer is not as large as that of the single buffer coder and may suffer a small loss of picture quality performance compared with a single loop coder implementation in an alternative embodiment to the multi sub buffer solution all sub coder loops feed into one common buffer store one stripe at a time however this embodiment has the disadvantage that the common buffer store would have to accept a data input at a maximum rate of 32 bit words at 144 mhz clock rate.