Julian has bought a new 42in HDTV with Freeview and wants to record programmes. Does he need to buy a digital video recorder?

I’ve just bought a Sony 42in Full HD TV. It’s connected to Freeview via an aerial. I want to record programmes. Most of the recording devices seem to include a Freeview tuner, but my TV has a Freeview tuner built in. I’m confused. Presumably I don’t need a machine with a tuner? Any ideas? Julian

You don’t need a machine with a Freeview tuner. In fact, you probably don’t need a machine at all. However, you may still want to buy one …

In the old days, people who wanted to record TV programmes bought a VCR or video cassette recorder to connect to their TV sets. The VCR had its own analogue TV tuner, so it didn’t actually record from the TV: it recorded programmes from the signal it got from the TV aerial. Indeed, this was a vital part of the VCR’s appeal: you could record something while watching a different TV programme.

Fast forward to today: the government has closed down analogue TV broadcasting and replaced it with a form of digital TV based on DVB-T (standard definition) and DVB-T2 (high definition). The digital signal that probably arrives through the same TV aerial has to be decoded by a Freeview or Freeview HD tuner, and Freeview tuners have been included in all TV sets sold in the UK since 2008.

Some TV sets allow users to record TV programmes directly to a USB hard drive, without using a VCR or DVR (digital video recorder). This involves plugging a USB memory stick or external hard drive into the correct USB port. In Sony Bravia TVs, this is the second USB port, labelled HDD Rec. See the section on USB HDD Recording in the Bravia’s European online i-Manual (versions for other regions may vary).

Be sure to use an external hard drive with its own power supply, rather than using the power available via the USB socket.

On its website, Sony lists 14 Bravia TVs that can record to an external hard drive, and 41 models that can play back from an external hard drive. There’s a good chance that your TV can record programmes, but it’s not guaranteed.

When you attach a USB storage device for recording purposes, the TV set will format it, and this will delete everything that’s already on the drive. For playback, Sony TVs can recognise FAT and exFAT file systems, but – unlike some other TVs – not Windows’ NTFS file system.

The biggest drawback with most Freeview TVs is that they only have one tuner. That’s fine if you use the timer to record something when you’re out, but not if you want to record one programme while watching another. To do this, you need two Freeview tuners.

However, there are other drawbacks with the USB recording technology, as generally implemented. (I can’t speak from experience of specific Sony Bravia models, so you’ll have to check what applies to your TV.)

The drawbacks mostly derive from the content providers’ war on copying, which they almost always regard as “piracy”. For a start, Sony’s i-Manual says that “Recording is not possible if the programme is not authorised by the operator”. Even if it is, the content providers don’t want you to be able to record a programme from a TV and then plug that into a PC. Sony and presumably other TVs therefore format USB devices using partitions that PCs can’t handle.

As a result, programmes recorded via USB may be digitally “locked” to that TV set. If so, you will not be able to “top and tail” or otherwise edit them, copy them to a different hard drive, or play them in another room or at a friend’s house. These were all things you could do with old-fashioned video tape.

And if your TV set dies, your recordings presumably won’t work on your new TV set, or not without some form of online registration. (I haven’t run into this, but please comment below if you have.)

To sum up: USB recording should work well for time-shifting and recording programmes when you’re out, using the Freeview EPG (electronic programme guide). However, USB drives don’t replace a VCR. For that, you need a DVR or PVR (personal video recorder).

The main advantage of having a DVR/PVR is that it will have one or two built-in Freeview tuners, so you can record one programme while watching another. Most also support “series link”, so you can elect to record every edition of Dr Who or whatever, rather than “taping” each one separately. Also, most work as DNLA servers, and can stream programmes to other DNLA-compatible Blu-ray players and TV sets over your home network.

Most PVRs allow you to back up recorded programmes to an external hard drive -- essential when you run out of space -- and some Panasonic models can record to, or copy programs to, DVD. However, there may be limitations on copying files off a PVR, and it could reformat your external hard drive, much like a TV set. In general, high-definition content and HDMI connections have more restrictions than standard-definition content.

Finally, there’s playback. Your Sony Bravia TV will play digital videos from your PC or other sources if you copy them to a USB memory stick or external hard drive in the FAT or preferably exFAT format. However, PVRs will generally handle a wider range of video and audio formats. Check the specs if you want to play back files in avi, DivX, Xvid and so on.

As far as I can see, the movie industry is driving us towards systems that can only be used for time-shifting and streaming. If you want to watch something more than once, you’ll have to buy it on DVD/Blu-ray or pay-per-view.