My DV capture device generates bad frames frequently (about 1/min).
These frames have colourful blocks (16x16 pixels) inside with some regular patterns.When I frameserv such a clip to VDub with AviSynth, I can see solid green (0x008600) areas, which consist of 2 or more 16x16 blocks.These areas are only green, when I go directly to the bad frame (^G and frame#).
When I play or preview the clip around the bad frame, the green color is completly gone and replaced by random blocks of the last frame before or after in the clip.It looks like, as if these areas are sort of "transparent" or unrendered by the DV codec.
Does someone know, what's happening here?

I'm asking, because I wanted to write a VDub filter for locating such bad frames by analysing solid areas of the specific colour.It made me curious to know the reason of this strange behaviour.

(I'm using now an AviSynth script, which can surely find such bad frames, but it's quite slow- works only in realtime).