Filter is intended for recovering quality of video ripped from DVD (for exmaple, when it contains 4 hours of video data), VideoCD or after decompressing by H.261, H.263, DivX 3, DivX 4, XviD.
Filter automatically determines the blockiness's strength on the frame and in the concrete part of it, preserving the maximum of details. Thus, filter will process marginally when on scenes with slow motion, while it will smooth very hard in the case of fast motion in the same film.
The main advantige of the filter is that it raise the integral quality in the most widespread PSNR metric in comparison with original film. That is, a film after decompression in comparison with original achieves the lower quality than a film after decompression and deblocking. (But for all that the original film is not used nowise, only decompressed data is used.)
