not sure, but i think uyvy decoding in ffdshow is b0rk when decoding to yuy2 in avisynth. chroma comes out fine, luma comes out twice the width, interleaved with flat grey samples. avisynth reports the resulting pitch as 1440 instead of 720.
also, yv12 output with uyvy input will use progressive downsampling (which i guess isn't really a bug)
[edit]
disregard that... i installed the latest build and all's well.
false alarm (i'm all happy now
)