View Full Version : Graphical A/V Switcher

02-04-2007, 07:56 AM
I've been searching for quite a while for a solution to my request. I want to make an on-screen digital A/V switcher using some kind of microcontroller, and the Propeller seems like it is capable.

This switch would need to take 4-8 inputs of component video and analog audio and somehow create a graphical (on-tv) interface to switch between the A/V inputs.

Does this seem possible? Hopefully you get what I'm trying to make here, if you don't, do tell.


02-04-2007, 08:24 AM
Hi Skyler

The Prop will do that easily.
Most high end commercial AV switcher units use high quality relay's to do the actual switching.
So do not feed the Audio and Video signals thru the Propeller .. that is a no no.

Use VB or Delphi to create the application..

Saw an application the other day that was developed by PowerBasic for Windows.
Looks pretty good as well ... fast .. www.powerbasic.com

Ronald Nollet Australia

Graham Stabler
02-04-2007, 08:29 AM
it can output video (for menu elements) and could control analogue switches or relays to I don't see why not. There are some threads where people have done video overlay, that might be a nice touch.


02-04-2007, 08:38 AM

Good suggestion Graham .. if Skyler wants to use a little LCD screen .
If he is going to use a PC with a monitor I personally would not brother.. too much stuffing around.

But as a self contained (totally standalone solution) the Prop would be awesome as it has Video capability.

Ronald Nollet Australia 40 C here now its Hot Damm Hot

02-05-2007, 03:08 AM
Thanks for the responses guys. :)

I forgot to mention that I'll be using this on a pretty large plasma, so it might be hard to make this look good. I hadn't thought about a relay, I'll look into it.

Thanks :)

T Chap
02-05-2007, 04:06 AM
Are you saying you want to be able to press a TV button to call up the graphic, say for example the Propeller graphic is on antenae B, you go to B, and there are your menu choices for all audio and vid? At that point you scroll though with some cursors and select the choices and press enter?

The computer interface would be ultra simple in Realbasic, but my guess is you are trying to do this while watching the TV, with minimal external hardware. The Prop could sit in a small box with the relays, 8 inputs from vid, 16 inputs from audio(8 stereo), 2 audio outs and 1 vid out from the relay matrix, one vid out from the Prop for graphics/menu.

Post Edited (originator) : 2/4/2007 9:31:29 PM GMT

02-05-2007, 04:09 AM
Just overlay text or graphics onto the switched video using Bean's video overlay object. The object will probably require some tweaking to work with component video, but other than that it should work fine.

One issue about overlaying on component video is that the overlay signal will be either green, red, or blue depending on what signal you overlay on. You may also be forced to overlay on the green signal since I believe that signal carries the video sync information.


02-05-2007, 04:41 AM
Originator has the idea. I want this to be as cheap as possible, which is why I think the propeller would be grand. Except, I want this to be a menu for when you turn on the TV, you can select inputs (TiVo, DVD, CD player, etc).

I don't need to do anything with overlay, although it would be pretty cool.

What I'm asking now, really, is how well do you think I could get the graphics looking? Also, at what resolution can the propeller output?

T Chap
02-05-2007, 05:47 AM
You would only need to get a ULN2803 transistor array which is an 8 channel device that will sink the low side of 8 relays, so you'd need one for the 8 vid in relays, one for the 8 stereo in relays, some bnc or rca connectors in a box with a Propeller and thats about it. There are a few different Prop dev boards you could use to save making boards.

The graphics will be marginal in my opinion compared to your TV's built in graphics "look and feel". Graphics on a PC could be much slicker, but then requires a PC sitting around at all times. Actually, I wouldn't even do the graphics on TV, I'd use a box with all the i/o's, with an LCD. You could have several cursor buttons, a write button, input your device names in the LCD menu, scroll through on the LCD and choose the device. This way, you elminate a step to click over to a "menu" channel to select inputs.

To get fancy, add an Xbee tranceiver to the remote and run it wirelessly to the relay board, adds cost, and hardware, but much cooler system.

Post Edited (originator) : 2/4/2007 10:51:22 PM GMT

02-05-2007, 06:43 AM
Thanks for the suggestions, yet again. This project is not for myself, really, but for a client.

I'll keep looking into it, I might just buy an integrated microITX board and take that route, just for the graphics.