BT848_E_VDELAY_LO
btwrite(0xfe, BT848_E_VDELAY_LO);
btwrite(geo->vdelay & 0xff, BT848_E_VDELAY_LO+off);
vdelay = btread(BT848_E_VDELAY_LO) + ((crop & 0xc0) << 2);
btwrite(vdelay, BT848_E_VDELAY_LO);