Page 74 of the ADV212 user's guide describes the VDATA format for 8-bit pixel data with BT.656 EAV/SAV codes. The tables on that page seem to suggest that VDATA[3:0] must be driven with '1111' data whenever the EAV/SAV start code 0xff is to be represented. This conflicts with other information in the ADV212 documentation that says VDATA[3:0] should be pulled low for 8-bit pixel data. I would like to know whether or not the user's guide Table 72 is correct or not. The BT.656 specification does not require the unused lower bits to have any particular value.
EDIT: Just found this on the forum: Re: EAV/SAV in ADV212 VDATA Bus
Hopefully this post is correct.