Xvid post-filter confusion

[chilledinsanity]

Hey, I'm confused by the different options in the post-processing options with Xvid. What the difference between deblocking vertical C and deblocking vertical Y? same for horizontal? and deringing? I tried using all the options, but the image looked too "smudged". Are there any combinations people recommend for quality?

[Manao]

The deblocking options try to smooth the blocks the codec may have created wile compressing. They are four deblocking, two horizontally ( ie it will smooth only horizontally ), two vertically. And for each direction, there is one which works in the chroma plane ( C ), and one in the luma plane ( Y ). If I remember well, the vertical and horizontal process are separated because human eyes is more sensitive to horizontal details than vertical ones.

Deringing tries to eliminate the little dots which may appear in the high contrast zones ( typically the edges of a face ). But it is a very destructive operation : it smoothes a lot.

Usually, I activate only deblocking ( the four ones ). But if the quality of the ripp was good, I deactivate all kind of postprocessing. On the other hand, I may use deringring if the picture shows a lot of ringing artefacts.

You may also want to try ffdshow, which allows other postprocessing methods : add noise and sharpen. They can be very usefull ( especially add noise ), to make the image more reallistic, if you had to filtered it heavily before compression. Moreover, the noise tends to hide the artefacts to the eyes.