Panasonic was a big player in kickstarting this whole Ultra HD Blu-ray thing. It, alongside Samsung, launched the first player in 2016, aiming high, with the UB900. 

That was a remarkable piece of home entertainment kit and soon after followed the UB700, a step down but none the less remarkable in its performance.

There's subsequently been the announcement of three more players. So what's the difference between all these Panasonic Ultra HD Blu-ray players and which one should you buy?

Let's walk you through it.

This is Panasonic's flagship Ultra HD Blu-ray player. It's built to be the best it can be and commands the highest price as a result. It offers outstanding picture quality when playing the latest Ultra HD Blu-ray discs, but it doubles up on offering audio skills too.

It's around the back that you'll find the biggest thing that marks this player out: it's loaded with analogue 7.1 audio connections above and beyond the dual HDMI you might use for Ultra HD Blu-ray playback. Those analogue audio connections are backed up by high-end audio hardware, aiming to make this player the best audio and video device it can be.

Take a step down to the UB700 and you're presented with a box that's not quite as plushly built, lacking the vibration reducing feet that audiophiles might be interested and a simpler design. 

Again, it's around the back where this story is really told: those 7.1 audio connections are stripped away and you're left with optical audio and those twin HDMI. This isn't designed to be an audio performer like the UB900, but it has the same video processing hardware, so the picture quality is the same. That makes it a solid proposition for those interested in the stunning visuals of Ultra HD Blu-ray.

The next step takes us into the 2017 launches, with the UB400. This makes a big change in design, shifting from the conventional 40mm box width of the 900 and 700, and taking on a smaller format. For purists, this makes the player itself look visually less conventional, but it is more compact, like a mini version of the UB700. 

You get the same video processing engine as the other two players, you also get twin HDMI and Wi-Fi so you can use the apps, like Netflix, to stream more 4K content. It looks like an ideal player, those twin HDMI meaning you can still hook it up to a TV and AV receiver.

There's actually a small software difference in the 2017 players too, that will let you change the level of the HDR effect - meaning you can boost the brightness without losing the detail, for example. (This will be coming to the UB900 and UB700 via a software update.)

The big loss from the UB400 is one of the HDMI sockets, meaning you lose your dedicated HDMI audio channel, although this is still the same compact box design as that other player, although the UB310 and 300 design is slightly more basic than the UB400.

Yes, the video processing engine is the same, so the pictures you get from your Ultra HD Blu-ray are powered by the same hardware as the UB900. There is also a Wi-Fi connection so you can use those apps such as Netflix. 

This is the lowest and least featured of the Ultra HD Blu-ray players that Panasonic offers, but surprise surprise, it uses the same video processing engine, so the picture quality is just as good from those 4K HDR discs as with the other players. 

What you lose in this box is the Wi-Fi connection, so if you want to use Netflix from the box, you'd need a wired connection. Can you live with that? Probably, because the TV you're using probably has its own Netflix player anyway.

The UB900's position was always to satisfy a demanding market and for the average user, it does a lot more than you'll need. At the same time the UB700 is an excellent player, but if you're only after a single HDMI output and the desire to play those discs, you might be satisfied with the UB300. 

There is a consideration however. We've tested the UB900 and the UB700 over a fairly long period of time and during those times we've had a number of updates to the boxes. Some of that is because they are new devices - but at the same time, if you leave your box disconnected, you won't have the benefit of online services or such easy updates. 

As for whether you want to use those internet apps: Panasonic's user interface on these players isn't as slick as it is on many smart TVs, so you'll probably have a much better experience using the apps on your smart TV or via your set-top box, like Sky Q or Virgin TV V6 for example. 

Prices are still to be confirmed, but with five levels of player, we're guessing that the price of getting yourself an Ultra HD Blu-ray player is going to drop substantially.