Getting rid of all my remote controls with one device (total newbie)

I am a total newbie, and want to create an automatic input switcher so I don't have to use any remotes to manually switch anymore.

Basically it will detect an active input and switch to that. I will have 3 HDMI inputs and one stereo rca input >going to> one HMDI out and one Coaxial audio out. RCA audio input is for my sonos, so when I start playing music it should auto play to the stereo without having to manually change inputs.

I've attached a diagram of my design. I have a couple questions.
Is this design good/feasible?
What Arduino parts should I be getting to make this work?

I've searched for such an existing device, but haven't found anything that works for me, and searched Arduino projects but haven't found anything quite like what I'm looking for.

Thanks for any input!

Searched for Arduino + video"?

no matter what search terms I use, I am unable to find any very relevant information.

Arduinos in general will not handle video signals. Maybe there are add on boards that can do it, and the Arduino is controlling that board.

Railroader:
Arduinos in general will not handle video signals. Maybe there are add on boards that can do it, and the Arduino is controlling that board.

It's also re-inventing the wheel. Plenty of HDMI matrixes on the market at low prices.

Even better!

AJLElectronics:
It's also re-inventing the wheel. Plenty of HDMI matrixes on the market at low prices.

Could you point me to one that switches automatically and also accepts an audio only input?

swordfish7:
Could you point me to one that switches automatically and also accepts an audio only input?

As you want digital output, you would use an analogue to digital converter before it goes into the matrix. Then you are only dealing with digital signals.

AJLElectronics:
As you want digital output, you would use an analogue to digital converter before it goes into the matrix. Then you are only dealing with digital signals.

So, there is one that accepts digital audio inputs?