Yeah people create all kind of complexitys that are just to much for sane Hardware Decoders
these block failures look exactly like the ones i experience with some X264 content and CoreAVC though might be not of the same nature but indeed ffdshow (libavcodec) doesn't show these kind of errors as it has a very primative error correction and can hide stream errors to some degress it seems (same for Mainconcepts Decoder) and these errors can also directly happen in the encoder not only because the stream has been damaged @ the transport. So i guess it would hide such occasional block errors very well from the viewer, CoreAVC can't do this but i guess Nvidias Hardware Decoder should also be able todo it like libavcodec does, as they expected it's being used for DVB watching