(Pocket-lint) - Nvidia has introduced all-new 4K HDR Shield TV media streaming devices, to replace its 2017 models.

As heavily rumoured and recently leaked, there are two new streamers - both of which now available through numerous retailers.

The cheaper of the two, the standard Nvidia Shield TV (reviewed here) has been dramatically redesigned, with its form factor now resembling a black cylinder that is best suited for hiding out of view around the back of a television.

It has Gigabit Ethernet and power ports on one end, HDMI 2.0 on the other. Wi-Fi (802.11ac) and Bluetooth 5.0 connectivity are included for wireless use, while a microSD card slot is available to extend its built-in storage beyond the included 8GB.

As well as the aesthetic, this year's entry-level model gains the new Nvidia Tegra X1+ processor and a 256 core GPU. This enables it to offer more features than ever before - and run more swiftly.

The headline new feature is AI Upscaling, which upconverts video to 4K, whether it be 480i or 1080p. It works on several key applications, including Netflix, Amazon Prime Video and YouTube and, having seen it in action ourselves, we have to say it can produce subtle, yet impressive results - without adding unwanted picture artefacts or motion smoothing.

The device comes with a new remote that takes AAA batteries, so doesn't need recharging, is backlit and also works as a microphone for Google Assistant support. It doesn't come with a game controller this time around, though. Instead, it is compatible with the existing Nvidia controller or an Xbox One or PS4 DualShock 4 equivalent.

The Shield TV runs the latest version of Android TV (currently 9 Pie) and therefore has Chromecast built-in and access to the thousands of apps on the Google Play Store. It is also compatible with Alexa, if you have an Echo device in the vicinity. And, Dolby Vision HDR and Dolby Atmos sound standards are both supported.

The same is true of the new step-up model, the Nvidia Shield TV Pro.

It also comes with the new remote and numerous other features detailed about. However, it adds more RAM - 3GB - and bigger storage - 16GB.

It can be used as a Plex media server (like the last generation Shield TV) with 1080p video transcoding ability, is Samsung Smartthings Hub-ready and is compatible with Lightspeed Studios games and Twitch broadcasting.

The Pro design is very similar to the former Shield devices, with two USB 3.0 ports on the rear.

Both Shield TVs are available now, with the standard model costing £149.99 (€159.99), while the Shield TV Pro will set you back £50 more, at £199.99 (€219.99).

Writing by Rik Henderson.