I think it will depend on price and capability. Most of the commercial video overlay chips have been discontinued but BOB-II and OSD-232 offer black & white overlays with reasonably sized letters. BasicAtom has a video overlay but it's fairly crude. I haven't seen a color chip. Will this be NTSC, PAL or both? Canl it overlay the picture or does it need a channel of its own? What's the expected cost?