[FFmpeg-user] How to force input-fieldorder and other fieldorder questions

[Christoph Gerstbauer]

Hello I want to use this filter:

https://ffmpeg.org/ffmpeg-filters.html#fieldorder

But for that I have to tell ffmpeg that the inputvideo has field order X 
to get fieldorder Y at the output. But how can I do that?
(I dont want to reencode the content with -vf "setfield=X".)
Example: I want to transcode a TFF source to a BFF target by shifting 
the picture one line.
At the yadif filter I can "say" to the filter that the incoming video 
has field order X.
How can I do that generally for ffmpeg?


Is this list correct?

#  -vf "fieldorder=tff" / -vf "fieldorder=bff"      -> transforms the 
field order by shifting the picture
#  -vf "setfield=tff"/-vf "setfield=bff"      -> just sets the field 
order of the frame without changing the frame

Some questions:

#  -top 0 / -top 1      -> is this a debrectaed version of the 
"fieldorder" filter? Or does this something else?
#  -ildct        -> is this only for DCT based codecs or can this flag 
also be used for ffv1 (wavelet) for example?

Best Regards
Christoph