[FFmpeg-user] Wanted: Fields-to-frames filter that does not add cosmetics

pdr0 pdr0 at shaw.ca
Fri Mar 5 17:35:09 EET 2021

Mark Filipak (ffmpeg) wrote
> 'yadif=mode=send_field' is one way to convert fields to frames at the same
> frame size and twice the 
> FR. It does it by repeating fields, but it also adds cosmetics -- it is,
> after all, a motion 
> interpolation filter.
> I seek a fields-to-frames filter that does not add cosmetics. In my
> pursuit, I look for such a 
> filter every time I peruse the filter docs for anything. I've yet to find
> such a filter.
> Do you know of a fields-to-frames filter that does not add cosmetics?

Yadif is not a motion interpolation filter

Motion interpolation implies resampling new data points in time - such as
optical flow (e.g. minterpolate or svpflow) when new "in-between" frames are
inserted using motion vectors. In contrast, yadif's interpolation is 1)
spatial, not temporal, and  2) Existing fields are not resampled in time
when converted to frames. ie. The motion characteristics are the same as the
input. eg. 59.94 samples/s interlaced source still has 59.94 same samples/s
progressive in the output, not some other retimed number . Or 23.976 samples
in 3:2 pulldown, still has 23.976 samples progressive in the output with
triplicates and duplicates. It's the same motion characteristics at the same
temporal positions - there is no "interpolation" of motion.

It sounds like you want a bob filter with simple spatial interpolation, such
as line doubling for the spatial interpolation (e.g.  nearest neighbor) ?
When you have missing scan lines, there is always some "cosmetics" . You
can't get something from nothing. Some type of spatial interpolation +/-
temporal interpolation (using data from adjacent fields) is always involved
to fill in the missing scan lines. Clarify how you want this to be done. 

Or, did you want field matching with decimation instead ?  eg. reconstruct
the original progressive frames that were organized in fields with pulldown
pattern , and decimating the duplicates. AKA "inverse telecine" ?

What kind of "fields to frames" did you want ?

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