Sets the post-processing mode. This controls how TFM should handle (or not handle)
any combed frames that come out of the field matching process. Possible options
are:
* You can also use the "clip2" parameter to specify an externally deinterlaced clip
from which TFM will take frames instead of doing the deinterlacing itself. See
the clip2 parameter description for more info and to see how the PP settings effect
operation with clip2.
* You can manually control what frames should be marked as combed as well as the
PP option through an overrides file (see the ovr parameter description)