If you have never owned a digital video recorder before, choosing your first DVR can be a daunting task. Or maybe you have owned a Sky+ or similar device but you have never had to think about the features you might want or need.

The first thing to think about is how you are going to receive your television channels.

Freesat is a relatively new offering from a sister company to freeview which provides free satellite broadcast channels with no subscription required. A satellite dish is required for freesat and will need to be budgeted for if you do not have one already.

Freeview is the digital television broadcast system that is in current use across the UK and will have completely replaced the old analogue signals entirely by 2012. If you can already receive freeview through your current aerial then no further equipment will be needed.

Most people can already receive freeview channels and is likely to be the choice for the vast majority. However freesat does have a number of advantages, primarily that it carries HD channels. Although freeview HD will be arriving late in 2009 to some areas there are no available freeview HD digital video recorders on the market currently.

Convergence is an oft used term in consumer electronics, namely the practise of making a single product that performs many roles. The iPhone is an example, taking an mp3 player and adding mobile telephone functionality. If you don’t have a DVD player, or yours is a little long in the tooth and doesn’t support up-scaling then a combined DVR and DVD player could be the answer. Similarly if you would like a DVD recorder or would like the ability to transfer recording made on your digital video recorder to a DVD for later viewing, or viewing in another room then a DVR with a built in DVD recorder is likely to save you money.

Although the number of DVR’s integrating a blu-ray player is limited, in the future I expect to see them more common place. With backwards compatibility with DVD’s a DVR with blu-ray functionality makes perfect sense for the high definition film buff.

To get the best from a digital video recorder I would recommend one with at two tuners. This will allow you to record one channel while watching another, or record two programmes at once while watching a previous recording. However if you are unlikely to need to record more than one thing at a time and your television has a built in tuner you can manage without a twin tuner.

If you own a high definition television set, it is worthwhile looking for digital video recorders that are capable of up-scaling. Up-scaling is the process of taking a standard definition television programme and using computational techniques to enlarge the image. Although many HD televisions can up-scale, the results from up-scaling digital video recorders and DVD players are frequently superior.

At the time of writing no terrestrial digital (freeview) recorders are available as HD freeview broadcasts have yet to start and apparently there is still some discussion ongoing about the specific implementation details. If you are a freesat user, there are a range of HD capable digital video recorders, many of which feature integrated blu-ray players.

The size of the in-built hard drive governs the number of recordings your digital video recorder can hold before you have to start deleting things. Although recordings will vary in size depending upon which channel the programme was recorded from, a rule of thumb is that you can store roughly half the number of hours of recordings as the hard disc size in GB. For instance a DVR with a 320GB hard disc should store around 160 hours of programmes. The size you look for will depend on the amount of television you watch and how much recording you intend to do, but for most people 320GB should give you plenty of space.