By Darren Waters
Technology editor, BBC News website
The first high definition DVD system, Blu-ray, has gone on sale in the UK promising a revolution in home cinema.
Blu-ray has hit the shops and HD-DVD is not far behind in the UK
The technology is expected to usher in the high definition era but there are many questions that pepole want answered before purchasing a player - or the rival format HD-DVD.
We answer a representative batch of questions sent to the BBC News website:
Is the time taken to retreive the data from one of these new disks any greater than what it is with current CDs and DVDs?
Steve Cassidy, Hampshire, UK
The loading time is longer than conventional DVD players for the first generation models. Read speeds on DVD players and DVD-Roms will improve over time.
Presumably, hi-def players will be backwards compatible and play all our old DVDs but will these players allow them to be "upscaled" (rendered at a higher picture quality)? Many current, standard definition machines do this so it would seem perverse if new ones did not.
Timothy Spence, Greenwich, London
The Samsung BD-P1000 we tested can upscale current DVD format movies to 1080p, offering significantly better viewing than stand alone DVD movies. But it should be remembered that upscaling to higher resolutions will not result in a picture as good as high definition. There is simply not enough picture information on an ordinary DVD.
If most film companies support Blu-ray and Blu-ray can hold far more data, what is the point of HD-DVD?
Jeff Culshaw, Liverpool, UK
A HD-DVD disk does hold less data than a Blu-ray equivalent. Supporters of the HD-DVD format say the 30GB disk has more than enough capacity for high definition movies.
Blu-ray supporters have said one disk can hold many different versions of a film including more extras but as yet few Blu-ray disks are being pushed to their limit.
HD-DVD has less supporters in the film studio world but some analysts feel the two technologies will achieve a stalemate, resulting in studios supporting both formats.
HD-DVD players are also considerably cheaper than Blu-ray players - in some cases less than half the price.
What price can we expect the players to fall to by 2012?
Rob Popay, Fetcham, Leatherhead, UK
That's a good question and one impossible to predict accurately. But I think it is fair to say that by 2012 the cost of a Blu-ray player will be much closer to the cost of an ordinary DVD player today.
I'd like to know why the Samsung player is more than twice the cost in the UK compared to America? £900.00 compared to $740.00
Mike, Torquay, UK
We asked Samsung and they told us: "The US market is a single market allowing the introduction of a single model produced, distributed, and sold in large volumes. Europe on the other hand requires the introduction of several model variants which will be produced and sold in lower volumes. There are also differences in purchases taxes between the two regions."
Does that answer your question?
Will either or both or these formats involve the farce that is region coding?
Rich, Turks and Caicos
Both Blu-ray and HD-DVD disks are expected to carry regional encoding - so that disks bought in one region will not work in another.
Hardware manufacturers lay this decision firmly at the feet of film studios and content producers.
Is HDTV required to reap the full benefits of HD-DVD/Blu-Ray's HD capabilities? If so, then what does this mean for me and other non-HDTV owners?
CyberKnight, Michigan, USA
I'm afraid you will need a HDTV to enjoy the benefits of Blu-ray or HD-DVD. So that's another considerable expense to think of.
What if neither take off, what's next?
Adeeb Ashfaq, Bradford,UK
Most analysts predict that one or both of the formats will be accepted into the mainstream.
While it is likely that in the long term films with even greater resolution will be available to buy on an as yet unspecified format, TVs too will also have to be made that can display these even higher definition pictures. But that is a long, long way off.
The other thing to consider is that high definition content will one day be widely available for download via the net to your PC or media extender box connected to your TV.
But with HD films requiring lots and lots of data, most people's broadband isn't yet equipped for the HD age.
How many times do movie studios expect us to buy the same movies in different formats?
John Dow, United Kingdom
We asked Samsung that question. They can only speak as a hardware firm and not as a film studio but they said: "It is perhaps better to look at it as blu-ray will give the consumers more choice.
Consumers will still be able to use traditional DVDs if they prefer as Samsung's Blu-Ray player allows existing DVD to be upscaled to 1080p - there will be no need to replace an entire movie library to use the Samsung BD-P1000."
Will any of these new fantastic formats iron-out the unacceptable inherent and noticable four percent speed-up problem which is currently found on every PAL DVD movie? (incured as a film transfer side -effect)
Will we be able to watch films at the correct speed (i.e 24 frames ber second) as the movie director originally intended?
Graham Mcdonald, Addlestone, Surrey
That's a very technical question and one we put to Samsung. Their answer was short: "No".
Is the difference from DVD a significant reason to upgrade? The advantages DVD had over VHS were great, e.g. higher quality visuals and audio, menus and extra features, optional audio and subtitle langauges, compact for storage, disks don't wear away etc etc... is it just video quality that makes the new formats better?
Tom Handon, Brighton, UK
Proponents of high definition DVD point to the better picture quality primarily but also say the disks will be able to offer more extras and features.
It's a question of whether or not you are satisfied with the picture quality of a standard DVD.
Why wasn't there a similar format war with DVD?
Stuart M, London, UK
All the hardware firms involved agreed standards before players were launched onto the market. This has not happened this time.
Is it true that Blu-ray disks are more likely to break then HD-DVD disks?
Mark Canner, Derbyshire, UK
I've heard of no evidence about one format's disk being more fragile than the other.
Will there be a significant cost difference between the players and movie releases for the two formats?
Liam Shelley, Birmingham, UK
HD-DVD players are about half the cost of a Blu-ray player. Movie prices are roughly the same.
Would it pass the "Mum" test? i.e. Would my Mum see an obvious and striking difference between a Blu-Ray and a HD-DVD picture? Technophiles may drool over the minutiae but it's consumers at "Mum" level who decide the format winner.
Richard Ross, Egginton, UK
That's a good question. My wife felt there was no great difference between current DVD and the Blu-ray movies. But to me there was an obvious improvement.
Often I think the factor is the size of your TV. TV screens over 32 inches tend to have the biggest impact.
Will this technology be helpful in preventing piracy?
Sameer Rafi, Karachi, Pakistan
Hardware manufacturers are confident that the anti-piracy measures on the new technologies are strong than those on DVD.
We will wait and see what happens...
I want to know which format will give me better quality video, which of the two have cheaper disc formats and which one is going to be more reliable?
Aiman Saleem, Quetta, Pakistan
The image quality on both players should be virtually indistinguishable and reliability is unlikely to be much of a factor.
The key issue will be content. Are your favourite movies supported by Blu-ray, HD-DVD or both? That's the big question.
How long will normal DVDs remain available? I'm perfectly happy with what I have at the moment, and don't want to be forced in to upgrading just because the films are no longer available in standard DVD format.
Tim Jinkerson, UK
Rest assured that DVDs will remain the dominant format for many years to come. Screen Digest predicts that only a quarter of all video disc sales will be high definition formats by 2010 - so that means DVD will remain in pole position for a long while yet.
So which format is better? We all know that Betamax was better than VHS, but that VHS won because it was marketed better. Could we see the same thing happen here?
Jon Boxall, London
Better is a value judgement. Both machines will support the highest possible picture quality.
My opinion - based on the reports of many analysts - is that both formats will co-exist for many years to come.
When will the player that supports both formats be available? Dual licensing should not be a problem. Otherwise, the constant tug-o-war will result in half the consumers being out of pocket, just like the old betamax-VHS-philips 2000 wars of the late 70's.
Richard Beaumont, Shipley, West Yorkshire
A number of firms have demonstrated disk technology that can support both formats. It remains to be seen if a dual format player becomes widely available and if it can license the technology from the competing camps.
What happens when one dies out and you've got the one that dies out? What do you do then?
Damien Pantony, Southwick, UK
Sell it on Ebay in 10 years time? The serious answer is that no-one honestly knows the outcome of the HD DVD war. If you are cautious, I'd advise waiting at least 12 months. It's very early days for the technology yet.
Will either of the new HD formats play the current DVD standard definition format, and home recorded DVDs (-R,+R and so forth)? And if not, are there any plans to produce dual format players which can cope with the current DVD formats.
Stephen J Haywood, Worksop, UK
Both formats are backwards compatible. Whether or not the players support formats such as DVD- or DVD+ depends on the individual manufacturer. Check before buying.