[noggin]

Just tried the update on a native interlaced 576/50i DVD.

Results for various deinterlace modes :

Software-ffmpeg - almost 50Hz motion but horrible vertical line artefacts and some jerkiness.
Software-blend - smeary motion, but without the vertical artefacts. Still some underlying jerkiness.
Deinterlace half - 25Hz motion with very poor vertical resolution (as though one field is being doubled and repeated and the other discarded)
YADIF - poor vertical resolution, jerkiness, and not convinced I'm seeing clean 50Hz motion - possibly the best solution.
Bob - very odd, very jerky as though fields/frames are being dropped left right and centre.
Bon Inverted - as above.
(This is very odd - if Bob and Bob-Inverted look the same then they aren't doing what they are supposed to) One of them should present fields in reverse (inverted) order. This isn't happening.

YADIF is an improvement - but nothing delivering the quality I'd get from a Raspberry Pi or a Chromebox. (Or the C2 when showing MPEG2 in a non-VOB wrapper...)

DD and DTS both being passed through. DTS has the drop outs. Haven't heard a DD drop out yet.

*EDIT - yep - DD drop outs too *