NardJ:
- cost < $50
I think that is rather fanciful.
The only reason Pi is so cheap and does so much is mass production.
For PAL or NTSC generation you are better off using a custom chip.
In the past i have worked with video codecs and they are not trivial or cheap to build from scratch.
NardJ:
chips don't have the horsepower to generate HDMI. .
Thet cannot generate PAL/NTSC either.
You will need a video generator for your display.
A bit like the graphics card on a PC.