I’ll be running 2 CAT5 cables from TV to a main hub where the DVD & Sky/Freesat box will be. Do I need a CAT5 to HDMI box for each feed (so 4 in total) or will 2 do?

Looking at these and they have 2 CAT5 inlet ports?
http://www.amazon.co.uk/gp/aw/d/B002ECYEYA/ref=redir_mdp_mobile?ref_=cm_sw_em_r_am_ip_am_gb

These systems normally use one cat 5 feed for power and one for signal which is why they have two cat 5 ports.

Is there a similar product that will do two devices (Sky & DVD) in one?

Why would you do this?

There are ones which can switch between two sources. I would avoid them personally, can be a nightmare to use – HDMI is designed so that the source and the destination have a little chat about what they will show. Switching two sources can make all that turn into a mess.

Also, whilst I know you can control some features of connected HDMI devices using the TV remote, does that work okay for fancy pants things like SKY+, or do you need something that relays remotes too?

HDMI cable doesn’t like long runs (so I’ve been told) so you run cat5 then use the converter boxes.

The cat 5 carries the HD picture and a standard co-ax runs the remote/magic eye.

It’s a while since I looked into so this may not be up to date but a couple of years ago there was two ways of doing what you want;

First an all singing all dancing 4×2 switch with HDBaseT outputs which will give you the option to connect 4 HDMI sources to 2 TV’s. Something like this;
http://www.hdconnectivity.com/hdmi-matrix/hybrid-4×2-hdbaset-matrix.html

Or a HDMI switch which will have inputs for 4 or 5 HDMI sources and a single HDMI output, which you then feed into some balluns like the ones you linked to.
http://www.hdconnectivity.com/5×1-hdmi-switch/hdmi-switch.html
http://www.hdconnectivity.com/extenders/hdmi-over-cat5-cat6-with-ir-extender.html

Controlling the whole thing can get clumsy though, juggling remote controls and other people in different rooms switching the wrong input/output.

Distributing multiple HDMI sources to multiple locations can be very tricky. Use CAT6 cable of the highest quality, make sure the cables are run with no other cables (particularly mains power) near it and with no sharp bends.

The HD Connectivity products are a minimum of what we would spec, cheaper extenders may work but it’s more hit and miss. Take in to account the maximum distances that the extenders can be run, even then there can be problems, we have had systems not working on only 20m before because of certain sources and displays. The HD Connectivity extenders will pass IR through for remote control of your source equipment.

Good luck.

The HD Connectivity products are a minimum of what we would spec

Sorry I should have made it clear in my post. I wasn’t recomending those specific components (I’ve never used them so no idea if they are good or bad), just using them as the first Google hit examples.

One thing is for sure, if you want to switch HDMI and reliably send it any distance it gets expensive very quickly.

Yes expensive is definitely the word!

Nothing wrong with the HD Connectivity stuff, we use it all the time, I just wouldn’t spend less than that.

Cat5 already installed in the wall – just looking for a definitive product that will take a signal from Sky box to TV and a DVD player to tv – It’s not multiple locations it’s just one tv in one room.

Don’t suppose you can just put the sources in the room and re-run the satellite cable? You’ve got cat5 for any networking you need, and that way all the complications of running video & IR signals a long distance are solved.

On the other hand, you have a house with 4 cat5 cables already installed in the walls, that is pretty handy!

I’ve also seen HDMI over gigabit lan, for if you have an existing network. I think it is quite expensive though (it is lossy compression, but almost certainly unnoticeable if your video is coming from something like a blueray disk or TV).

Don’t suppose you can just put the sources in the room and re-run the satellite cable? You’ve got cat5 for any networking you need, and that way all the complications of running video & IR signals a long distance are solved.

I could but didn’t want to as we would prefer not to have any cables etc showing hence the reason the cat5s, coax, etc are buried in the wall.

Basically Looking to see if this cat5 to hdmi converter is what I need at both the source end (sky box) and tv end…

It might work, it might not. In theory, it should, but with HDMI in theory is not the same as in practice, which depends on what device is at both ends and the ethernet cable in the middle. Only way you can find out is to buy and try and send it back if it doesn’t work.

Even fancy expensive kit can be hard to get going; we had a *very* expensive HDMI -> cat6 balun pair, going along something ludicrous like a 200m run of paired cat6 cables, which in theory would work even if one cable failed, with a very expensive cinema projector at one end, and that was an absolute pig to get working.