The overlap buffer behaves like a shift-register chain of a traditional filter. The key difference is that the data in the overlap buffer does not shift but the pointers do after every iteration. The initial value of the overlap buffer should be all zeros. To simplify the manipulation of the overlap buffer, the depth of the overlap buffer is set to an integer power of two. The depth of overlap buffer is given by the following equation.
For example, an 89-tap filter has an overlap buffer of 128 samples.