There are a growing number of devices around that can play back H.264 encoded video, but unless you have a very fast computer, it can be time-consuming converting existing files.

Elgato’s Turbo.264 is intended for Mac users who want to take content with them or play it on an AppleTV.

It’s a USB2 device that’s a little larger than a first-generation iPod shuffle and leaves you free to get on with work while it crunches through your video files. At its simplest, you just install the software, then drag files onto the application, choose one of two iPod settings, PSP or AppleTV, and away it goes. It also works with most Quicktime software and files appear automatically in iTunes.

In our tests, we found that encoding took roughly 1.5 times the running time of a video file - a 58-second clip with lots of action encoded in one minute 25 seconds. By comparison, on our PowerBook G4 1.67GHz, encoding the same file in software took between five and eight-and-a-half minutes; obviously, faster processors won’t see such a benefit.

If time is the most important thing to you, then the Turbo.264 is a great bit of kit, but the files it produced weren’t shrunk that much compared to the MPEG2 originals with just the preset options – there’s no room for tweaking. Using MPEG Streamclip instead, for example, we achieved almost half the size (12.7MB instead of 21.5MB), albeit via a process five times longer.

Tools like Ffmpeg will offer you much more control, potentially giving a slightly better picture.That said, the results are perfectly watchable, and aspect ratios are retained. If you’ve got a lot of content you want to convert, an older Mac and file size isn’t too much of a worry, and £70 could be well worth the time this device will save you.