TV Video Overlay circuitry?

[mitch]

I need to produce a simple, very low cost product which is a TV set-top
box to be connected inline with the TV signal cable that will generate
simple preprogrammed animated overlays. The TV program image will not
be affected, just overlaid.

I have Googled this but only find add-on graphics cards for PCs which
cost several hundred dollars. I need something which can be mass
produced cheaply.

Could this be manufactured cheaply (say under $10-$20)?
What kind of circuitry/chips would I need?
How do I program the animations?
Where can I find out about this?

Could someone please point me in the right direction?

Thanks in advance.

Mitch

 

[Matthias Melcher]

mitch wrote:

I have Googled this but only find add-on graphics cards for PCs which
cost several hundred dollars. I need something which can be mass
produced cheaply.

Google for 'OSD' or On Screen Display, Character Generator and Genlock.
These chips are usually used for Closed Captioning or Videotext, so they
are limited to rendering text and simple block graphics, sometimes in
color. The communications standard is serial protocol via i2c bus.

There are also projects out there using PIC's to generate video images.
Using this technique for overlays would be possible, too. Google for
"pic-pong".

 

[Pooh Bear]

mitch wrote:

I need to produce a simple, very low cost product which is a TV set-top
box to be connected inline with the TV signal cable

Which type of signal ? ( see below )

that will generate
simple preprogrammed animated overlays. The TV program image will not
be affected, just overlaid.

I have Googled this but only find add-on graphics cards for PCs which
cost several hundred dollars. I need something which can be mass
produced cheaply.

Could this be manufactured cheaply (say under $10-$20)?
What kind of circuitry/chips would I need?
How do I program the animations?
Where can I find out about this?

Could someone please point me in the right direction?

First off you need to determine if the set-top box is doing the overlay to
an RF signal or simply a video signal. Or indeed demodulating a RF signal
and supplying a video signal to the TV set.

There's 3 common ways to get a picture signal into a TV set.

1. RF signal ( using an aerial / antenna connector )
2. Composite video ( usually on an RCA jack )
3. RGB input ( in Europe this would be on a SCART connector - dunno
about USA - the mini-DIN 'SVHS connector' also does RGB )

All of these possibilites require differerent levels of complexity. RF in /
out requires an RF receiver and re-modulator for example where as the other
2 don't.

If you need to ask these questions I seriously hope you don't plan to
attempt the project yourself.

Graham

 

[mitch]

Hugely many thanks for your replies. As you can see, my knowledge in
this area is minimal.

I don't intend to attempt this project myself, although I may program
the animations if its not too tricky.

At this stage I'm simply trying to find out if its possible and what
sort of costs might be involved, both for product development and
manufactured unit cost.

Ideally I want this to work with broadcast TV anywhere in the developed
world, but I recognise that the product would probably have to be made
in market-specific (NTSC / PAL) versions. And then there's digital TV
which presumably is different again?

The animations will be amorphous shapes, not text.

I was hoping to be able to use the antenna connector as it seems the
simplest for the consumer to connect. My VCR/DVD recorder has the
antenna cable going into it, and then coming out to the TV. I envisage
a similar arrangement with my product receiving the cable from a
VCR/DVD and then coming out to the TV. This presumably would then allow
my product to work with live TV broadcasts as well as recorded
material?

What unit costs might an RF receiver & re-modulator be in production? I
have absolutely no idea?

Thanks

Mitch