[FFmpeg-user] fieldmatch "marked as interlaced" -- doesn't work

[Mark Filipak (ffmpeg)]

I hoped that "marked as interlaced" [1] meant that

'select=expr=not(eq(interlace_type\,TOPFIRST)+eq(interlace_type\,BOTTOMFIRST))' [2]

would work. However, the 'select' doesn't work. I'm counting on the 'select' working -- not working 
is a complete show stopper.

Is there some other species of "marked as interlaced" that will make the 'select' work?

Thanks,
Mark.

[1] From https://ffmpeg.org/ffmpeg-filters.html#fieldmatch
"The separation of the field matching and the decimation is notably
motivated by the possibility of inserting a de-interlacing filter
fallback between the two. If the source has mixed telecined and real
interlaced content, fieldmatch will not be able to match fields for
the interlaced parts. But these remaining combed frames will be
*marked as interlaced*, and thus can be de-interlaced by a later
filter such as yadif before decimation."

[2] From https://ffmpeg.org/ffmpeg-filters.html#select_002c-aselect
"interlace_type (video only)
"    The frame interlace type. It can assume one of the following values:
"    PROGRESSIVE
"        The frame is progressive (not interlaced).
"    TOPFIRST
"        The frame is top-field-first.
"    BOTTOMFIRST
"        The frame is bottom-field-first."

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