What are the advantages of Blu-ray discs over DVDs? Which TV do you need to tap into the new disc's full potential? Can Blu-ray players also play back DVDs in decent quality? Here, we answer some of the most important questions for Blu-ray beginners.

Blu-ray is named after the blue laser that players use to read the discs.

Blu-ray discs are more expensive than traditional DVDs, but are they better? Is now the time to make the switch? And, if so, what kind of TV will you need? Is "HD Ready" enough, or does it simply have to be "full HD"? There are loads of possible questions - we'll answer some of them in this Blu-ray special.

Like the DVD, Blu-ray is also a digital, optical storage medium. It is capable of storing five times as much data as a DVD, meaning it can contain a full movie in HD quality, along with multichannel sound and masses of bonus material.

The Blu-ray takes its name from the blue laser that players use to read the disc's data. The first Blu-ray discs hit the market in fall 2006, coinciding with the release of the first Blu-ray player, the Samsung BD-P 1000.

Yes. Sharpness, detail reproduction, color - everything is better! The five-fold increase in resolution results in a huge qualitative gain. Every Blu-ray disc we've tested so far has comprehensively trounced its DVD counterpart. Even the less clued-in users will notice the difference immediately, and the bigger the screen, the more obvious the difference will be.

It's not always the same. Extremely expensive, elaborate Blu-ray productions, such as "Casino Royale" or "Mission: Impossible 3", will beat the corresponding DVDs by light-years. Blu-ray versions of older movies, such as "The Silence of the Lambs" or "Rocky", often show only a slight improvement over the DVD, unless the movie been remastered.

Setup options: Not all Blu-ray players have adjustable picture controls, such as those seen here in Pioneer's BD-LX91.

The playback quality of movies shows only minimal variation. The player doesn't actually have to do very much in this case - after all, it simply has to relay the data present on the disc (a 1080p picture at 24 Hz), something all players can manage without problems. Some devices, however, have an additional video equalizer that you can use to spruce up poorly mastered discs.

The situation is different for documentaries and concert recordings, since these are often mastered in the qualitatively poorer 1080i format, meaning either the player or the TV needs to de-interlace the signal. The ability of individual players to handle this task varies hugely. For this reason, our test laboratory evaluates 1080p and 1080i material separately during visual testing.

Yes, if the Blu-ray was produced with HD sound in the form of Dolby True HD, DTS-HD Master Audio, DTS-HD High Resolution or multichannel PCM. With these formats, you can hear the difference even on middle-of-the-range sound systems. If, on the other hand, the Blu-ray only uses normal Dolby or DTS audio, the sound is only marginally better than that of a DVD.

Yes - besides the higher purchase price, there's one further disadvantage: It takes significantly longer for the player to start up from standby mode and to load discs. This is to do with the complexity of the material and the significantly larger amounts of data involved. Fast-forward and rewind are also not as fast as with DVDs.

Yes, they can, but DVD playback exhibits considerable differences in quality compared to Blu-ray playback. No wonder: Here, the device has to both de-interlace the signal and up-scale it to 1080p.

Very few Blu-ray players play back DVDs in top quality, and those that can are largely found in the higher price range. An insider's tip: The PlayStation 3 plays back both DVDs and Blu-rays excellently.

High-end players, such as the Denon DVD-3800 BD (pictured here), are top-notch for DVD playback.

No, they can't. This has to do with the laser that's used to read the disc. The data tracks on a Blu-ray are much finer, meaning the laser beam must also be significantly smaller. For the DVD, players use a laser with a wavelength of 650 nanometers, while Blu-rays require a laser with a wavelength of 405 nanometers.

Yes, now is a good time. New Blu-ray players are now very sophisticated and well beyond the teething problems of the early models.

Blu-ray players from well-known manufacturers currently range from around 180 GBP all the way up to more than 1,800 GBP.

Bargain hunting: You can occasionally find Blu-ray movies for as little as 13 GBP.

Between about 18 and 26 GBP. Chain-stores frequently offer blockbusters, such as "Quantum of Solace" or "I Am Legend", for between 18 and 26 GBP. Bargain hunters can really get their money's worth.

You needn't worry about the supply of movies, since all major movies are now also released on Blu-ray - around 50 releases per month. Lesser-known productions and niche-market movies, on the other hand, will often appear later, or not at all, on Blu-ray. Underground-movie fans, in particular, should take their time about getting rid of their DVD player.

Lots! The PS3 is one of the best players on the market. This is partly to do with its numerous firmware updates, which ensure that the software is always in line with the latest technology. The disadvantages: It's still very expensive, uses a lot of power, and only outputs HD sound-formats in PCM format - that is, not in the better-sounding bitstream form.

Excellent playback of Blu-rays and DVDs: Sony's PlayStation 3.

Yes. You can already buy the first recorders in Japan, the USA, and France, but, at about 900 GBP, these are still rather expensive. When it comes to models for the UK market, there's a cagey silence from the various major manufacturers.

So far, only Panasonic has announced any actual plans - the manufacturer's first two models are expected to cost about 900 and 1,000 GBP, depending on the size of the hard disk, when they're released early this summer.

It's impossible to say. For sure, Blu-ray will be replaced at some point, but it's unlikely to disappear from the marketplace for a significant amount of time. We're seeing the same thing with DVD, whose sales remain huge despite competition from Blu-ray.

If you want to watch movies on Blu-ray, you'll need a modern flat-panel TV bearing the HD Ready logo or - better yet - with full HD resolution. Old CRT TVs cannot display the high-definition picture at all.

HD Ready TVs render excellent picture quality with Blu-rays, although the quality is still nowhere near as good as on full HD models. Only the latter can display the Blu-ray's full-HD-resolution picture (1920 x 1080 pixels) without scaling. HD Ready TVs can display "only" 1280 x 720 pixels, so they must down-scale higher resolutions.

Even older players, such as the Sony BDP-S300, can output Blu-rays in 24p format.

Yes - or at least all that are currently on sale. When buying a new TV, therefore, you should check that it is compatible with 24p, as almost all new models are. 24p is a signal format that was designed especially for Blu-ray - using this format, Blu-ray movies should appear "judder-free" and in the originally recorded frame rate. This, however, is often not the case in reality: A "micro-judder" becomes visible, especially during slow, horizontal camera pans.

The solution: Choose to output in 24p format in the Blu-ray player's menu. This should give more fluid playback, but is still no guarantee: While all new TVs accept 24p signals, they may also modify them using electronic video processing. Refer to our individual TV tests to find out whether a display handles 24p-playback perfectly.

Using the HDMI connection. The "High Definition Multimedia Interface" is the consumer-electronics sector's first, fully digital, universal interface for transmitting audio and video data.

The HDMI connection permits transmission of uncompressed picture and sound information. In short, the HDMI cable does it all: audio, video, and control. It also makes it possible to enjoy new Blu-ray audio formats such as DTS-HD High Resolution, Dolby Digital Plus and Dolby TrueHD.

HDMI: The do-it-all cable.

Yes, there are three different codes, for the regions A, B, and C. Europe belongs to Region B, alongside Africa and Australia. This is much clearer than for DVDs, which are divided into no less than eight region codes. Furthermore, neither Warner nor Paramount nor Universal currently uses country-restrictions on its Blu-ray releases, meaning, for example, that a Blu-ray from the USA will generally play fine on German players.

One world, three regions: Blu-ray doesn't split the globe up quite as dramatically as DVD does.

Now, yes. Initially, movie companies would even sometimes put less bonus material on them than on DVDs, but the tables have turned: The Blu-ray will almost always adopt the DVD bonus material and then sweeten it with a few tasty extras.

Bonus View features are productions that use both of the player's video decoders in order to display two images simultaneously, allowing picture-in-picture display. These picture-in-picture tracks can display scenes from the movie studio or interviews with the starring actors while the movie itself plays.

BD-Live is an interactive feature that makes it possible for Blu-ray players to download additional content from the Internet, such as interviews or deleted scenes. The player must support the BD 2.0 profile, which requires a local storage capacity of one gigabyte and a network connection. Most of the time, you can recognize compatible devices by the BD-Live logo on the front. Other Blu-ray players can be made internet-capable via firmware updates.

This logo indicates that a player supports BD-Live.

A player's operating software is known as "firmware", and is responsible for handling all of the player's tasks. Firmware updates improve and extend the player's performance - as in the PC sector, for example - and keep the device up to date.

Technically demanding Blu-rays with many features may either not run at all on old players or will do so only with certain limitations. Then, it's necessary to update the firmware. The updates can come via the network interface, or you can burn them onto a CD and load them into the player that way.