Added field=-3/-4.
Changed back the behavior of field=-2/-1.
Set output GetParity.
Fixed processing when BFF.
Added parameter `pass`.
Fixed double rate mode.
Added parameter `thr`.
Added parameter `debug`.
Added support to read frame property _FieldBased.
Set frame property _FieldBased to 0.
Added parameter edeint.
Fixed double rate.
Added field option -2.
Port of the VapourSynth plugin Bwdif.