You can add any file extension you want to the list of file types that will be transcoded, so you should be able to get any common format to work with your chosen streaming device. MKV video files, for example, can prove tricky for machines running Windows, as well as Xbox 360 and Playstation 3 games consoles. In order to make this function work you have to download the Media Station application for your NAS and then enable transcoding. This ability is important for those with large and varied media libraries using media centre applications that can't open all types of files.

On-the-fly video and audio transcoding is where this device should excel, thanks to its dual-core, 1.6GHz Intel Atom processor and 1GB of RAM.

A pair of cooling fans output hot air at the rear of the case, so you'll want to make sure there is ample space behind the NAS to ensure peak performance. These include three USB2 ports - one on the front and two at the back - and a pair of high-speed USB3 ports on the rear. It's larger than some 4-bay enclosures, but you get the more ports you'd expect from a NAS. In typical Synology style, the DS415play is a plain but handsome-looking device.

You don't need tools to fit 3.5in disks, but you'll need a screwdriver if you're fitting 2.5in disks. Fitting disks is easy: you remove the front panel, push a lever and pull on the handle at the front of each caddy to slide them out. Our DS415play came as an enclosure without disks, as usual with Synology NAS drives, so we used four 3TB WD Red NAS disks for our tests.

This ability returns with the DS415play, although the version we're testing has double the number of drive bays, which could make it the ultimate media server for anyone with a vast library. Last year's media-focused Synology DS214play was a resounding success in our tests, with its powerful processor able to transcode video on the fly to stream them to devices that would otherwise not able to play them.

Plex media server synology ds415+