@AmigaPixel,
Actually the DCTV worked its magic on either 3bit or 4bit, not 4bit and 8bit, Amiga images and animations depending on which setting was selected. An amazing bit of hardware and software that was never fully taken advantage of. 3bit and 4bit animations could fly on an A3000 with a Warp Engine 040/40mHz.
Since most HDTV's will also display the older NTSC format, there is not much need or demand for a device that can convert the NTSC format to a HDTV signal.