"VD hack" needed when (threads > 1) because multithreading also involve encoding lag of VfW as B-frames (and in previous was described decoding lag of VfW). I need mention that "VD hack" option only fix encoding lag not decoding lag (of course you need encode in VirtualDub[Mod] for correct work of this option) but if you decode with DirectShow filter there is not decoding lag (so the decoding lag of B-frames is problem for editing [when using VfW decoder] but not for viewing in DirectShow players).

And about chroma interlaced downsampling bug:
Yes, it treats image as progressive during RGB->YV12 (YUV -> YV12) conversion because during decoding it also treats it as progressive (and if I would make RGB->YV12 conversion in there other way than you will have greater bugs during decoding).

Originally Posted by jagabo
Interlaced mode in the version of x264vfw I have installed (the most recent one from Death the Sheep) doesn't work quite right. The chroma channels are handled incorrectly. You should check yours carefully. The command line version of x264 handled interlace properly.
CLI version support only YV12 as input so it don't make any colorspace conversions. So would you see such bug or not depends of how you make RGB->YV12 colorspace conversion (revert conversion during decoding also important) which you feed to CLI x264.