[FFmpeg-user] Objectively best deinterlacer?

[Leo Izen]

Is there any filter which is objectively best at deinterlacing? I like 
the results from -filter:v 'pp=fd' but I didn't know if some others such 
as -filter:v 'w3fdif' were objectively better. Is there some kind of metric?

Also, when deinterlacing a fully-interlaced video with -filter:v w3fdif, 
the filter doubles the framerate. I have been dealing with this (rather 
than dropping the frames) via
-filter:v 'w3fdif,select=outputs=2:expr=mod(n\,2)+1,blend'
although I'm not sure if this is the right way to do this. (Although I 
appreciate that FFmpeg is smart enough to realize that select outputs 
two streams and blend takes two as an input, so I don't have to futz 
with [v] stuff.)

Should I go about this with w3fdif? Should I be happy with -filter:v 
pp=fd? I noticed that w3fdif is very slow, as in I got 13 fps filter 
time on a 1080p/60i input, where yadif and pp=fd encoded as fast as the 
encoder would work (which is faster than realtime.)

Thanks,

Leo Izen