[follower]

In the past I've thought about overlaying Twitter on live TV but don't watch live TV enough these days to be particularly motivated to follow through.

I even picked up a "Breakout Board for MAX7456 On Screen Display" http://www.sparkfun.com/products/9168 which combined with a networked Arduino should be enough to get something happening.

(I am available for consulting if you want someone else to do all the fun work for you. :) )

[downx3]

That's pretty cool. I was thinking about something similar. Just the ability to easily blend video signals. Say two inputs on the TV.

It would be good to then plugin a 'computer' something like the Raspberry Pi, that would overlay the existing signal, or merge two video inputs (Would this be simple digitally?).

It would be nice if there was meta info available alongside a program, that you could hook into somehow, so you could do something useful with it. A cue sheet or something. Having meta info about a playing scene could be useful. Digitized credits would be nice.

[follower]

The biggest issue is with the move to digital from analogue TV signals. Then you have the issue that any significant high resolution image manipulation requires decent processing power.

Even more complications arise when you also factor in control technologies like HDCP.

I was about to mention work that had been done by a guy "bunnie" and discovered it's actually advanced from a hack to an actual product:

* http://kosagi.com/w/index.php?title=NeTV_Main_Page

* http://adafruit.com/products/609

Looks like that could be exactly what you're looking for. :)