[MEncoder-users] crop, filmdint vs. filmdint=crop (or filmdint, crop)

[Jason Simpson]

I am attempting to transcode some ATSC MPEG-2 captures that have extra
non-video data in the top eight lines (the original streams are
1920x1088 pixels). These video streams are also very frequently hybrid
interlace/telecined content and the original streams include MPEG-2
field flags.

If I crop and detelecine/deinterlace using -vf
crop=1920:1080:0:8,filmdint, I get a clean picture but very bad motion
with speedups and slowdowns because the crop appears to have stomped
on the MPEG-2 field flags that filmdint wants to see to do a good job
on mixed content.

If I use put filmdint first and use its built-in crop (or if I follow
filmdint with crop) using -vf filmdint=crop=1920:1080:0:8, I get
smooth output (for the 24fps parts at least, which is what I want),
but I get green and purple chroma artifacts at the top of the video
frame, presumably from the influence of the data that has been
cropped. (These same chroma artifacts appear just below the lines I
want to crop if the crop option is left out.)

Is there an alternative way to do this that will allow filmdint to see
the field flags, but to also crop the frames without artifacts?

   Thanks.
   -jrs