A post-processing manager provides reconstructed block based picture
post-processing that is uncoupled from picture decoding by dividing a
reconstructed image that was encoded using block based processing into
non-overlapping blocks, creating a DC image by computing the DC value of
each block, creating a zero mean image by subtracting the DC value of
each block from the corresponding pixels of that block, filtering the DC
image and adding the filtered DC image to the zero mean image. A weak
filtering operation can be applied to reduce blocking artifacts, and a
strong filtering operation can be applied to smooth luminance
transitions.