Video sample?

Hi,

it is possible to output video with a arduino.

Do you think it is also possible to sample video? I dont think about a full frame capture of course, just a few color pixel scattered over the screen. Would be nice to make some DIY TV ambient light...

Carsten

At 16mhz and about a k of ram, the standard arduino is far from capable of serious video, unfortunately. As far as generating video sources, its somewhat possible, but not very powerful, if your just interested in simple generation, you might want to check these out:

http://dailyduino.com/archives/368

http://little-scale.blogspot.com/2009/04/how-to-use-arduino-to-generate-glitchy.html

hope these can get you started, you might wanna poke around the forums, i recall someone cooking up a video shield. If you want some serious video generation, check out the parallax propellor chips which can natively output color graphics.

Of course I don't want to sample a whole screen.

Would be enough to sample one Line (or even parts of it). If the next sample is the next frame that would be tolerable.

However, it seems that the color information is packed in a very tricky way into a scanline which I dont understand for now.

But the reason for asking is also to gather information and ideas, maybe someone knows an external chip which can be used for such a thing...

Carsten

Did you take a look at these threads? http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1236984140/13#13 http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1220054359/0

Yes, I found theese topics during my search, very intresting, however I cant see how this could help me with my "problem".

Maybe I should go for getting the signal from a RGB (SCART) connection, however that would limit the project to DVD->TV (because thats the only path where I have RGB signals).

Carsten

Sounds like you're trying to implement an Ambilight. If so, I recall seeing a thread on that, too. For that, you basically want something to average the whole frame down to something like 3x3 pixels, and then send those colors to the lamps.

http://www.welivelikethis.net/2007/07/diy_ambilight.html

http://blog.makezine.com/archive/2008/06/build_your_own_ambilight.html

I don't know if you can sample video on the Arduino itself, especially if you're talking about faster HD rather than slow NTSC. One issue is when there's a tiny little spot of yellow in a big blue scene, you don't want the tiny yellow pixel to be chosen for the ambilight. That's why the other sources downsample to get good dominant colors. So, if you're playing video from your PC instead of a dedicated player, these solutions sample the PC's video output and talk to the Arduino Ambilight circuits directly.