This of course could be done in multiple ways. I am assuming you have a video capture card on your computer and are using Windows. This simplest of methods of course is to just hit the input button on your remote to switch between the TV and the player. BUT besides that, you could just create a campaign that has multiple timelines where one is a full screen. Here you will place VLC on a common channel that will show your TV content. On the next timeline, you will have the screen to match your needs for your signage stuff like your menu specials. I would also keep a small viewer window for the VLC on here so you can monitor when the commercial is over and know when to hit the button. Now you should also download the other exe file I mentioned in this other article, so that you can either mute or lower the volume for the TV content when you are on the other timeline and have it un-mute when you switch back to the VLC timeline.
So as far as the Audrino is concerned, follow the video tutorials and they will show you how to switch between timeline with the triggers and events. You could also do this with a mobile phone or tablet as well. Those are just a few thoughts that I think could be easy for you to do
