[PD] signal continuity and filtering with block~ 2*N 2

I have been designing some externals for subband adaptive filtering, and I realized there was something wrong with my approach.

I needed the block~ 2*N 2 inside a subpatch, to get a block of N new samples, while holding the N old samples for filtering. The actual filtering operation works on only the N new samples, leaving the N old samples the same.

So, the thing is, I want to circumvent the addition of overlapping blocks, and have the output based only on the samples which have been filtered. I came up with one method, called reformat~, which does this:

signal : | N old samples | N new samples | output: | N new samples | zeros--------------|

It just moves N samples from the front to the back. This is resulting in clicking and brief cuts in the output.

So far, I have coded all necessary parts, except the adaptation of filter coefficients. There may still be something wrong with the convolution routine, but (when not using reformat~) the signal shows good continuity and no clicks.

Any thoughts? Suggestions?

Chuck