Concerning r6388, I think video_filter16 should look like this:
INT32 leftuppix = - hres - 2;//not -4 now, it's in pixels now, not bytes
//and so on
...
INT32 leftupcvg = - hres - 2;//still -2
...
pix = vbuff[leftuppix ^ WORD_ADDR_XOR];
cvg = hbuff[leftupcvg ^ BYTE_ADDR_XOR] & 3;
...
leftupcvg++;//these two may be merged now
leftuppix++;