few questions on blu-ray

[oxygenuk]

a few simple to answer questions for some of you i think, anyway here goes :P ..

1. will all blu-ray players support dvd playback? or will there be dual laser blu-ray players thast u need so u can play dvd format?
2. will there be home cinema/hifi systems wth blu-ray integregated like dvd home cinema/hifi systems nowdays, and how longer after the public release of blu-ray in the uk u think?
3. how much diffrence in picture and sound will there be? :P :P

[Blu-Wave]

Hi O2UK,

Although not mandatory, all existing Blu-ray machines support DVD playback - in fact, Panasonic's new 50GB machine can also record on DVD-RAM and DVD-R. In recognition of the fact that there are rather a lot of CDs and DVDs about, and that for some recording purposes a cheaper, lower capacity disc such as a DVD or CD is all that is required (even 1.44MB floppy discs are still being used), Sony and Philips have developed three laser optical heads - 405nm for BD, 560nm for DVD and 780nm for CD. This ensures that full compatibility with virtually all recognised CD-sized formats is achievable. Whilst Sony's three laser head integrates all three lasers on to the same substrate, so should eventually become more compact and cheaper, Philips' head uses three standard laser diodes - so it can be optimised for various purposes by varying each laser output -for example, a machine which only reads DVDs and CDs need less power than one which writes, and lower power laser diodes are typically cheaper. Philips' new head is also roughly the same size as one of its current DVD heads. Both types of head can potentially playback and record BD, DVD and CD, and Sony is even developing a universal machine for PCs that can handle HD-DVDs too! :shock:

As one of the primary objectives of BD is to provide high quality high definition (1920 by 1080p24 or better) in the home, and backwards compatibility with DVD and CD is the norm, it is likely that a high end unit would act like a modern universal machine - assuming DVDA and SACD support too, of course. There are still "sound" arguments for employing a dedicated CD/SACD machine too, or even a dedicated CD machine if you have few SACDs, but most people would be happy a mid-range universal machine of this type, whilst lower cost machines that might offer playback only of BD but record to DVD, say - and even some with a hard drive too, would be pretty acceptable to many. LG have been talking about releasing a combined BD/HD machine (with a 200GB hard drive) since the end of last year, and it was due this month, but as it's all gone a bit quiet and they have consistently refused to discuss BD capacity, they may have had to re-engineer it for 50GB dual-layer in the light of Panasonic's 50GB machine. Incidently, the 50GB Panasonic DMR-E700BD is described as the top model of their Diga DVD Recorder range, and as mentioned earlier, it can also record on DVD-RAM and DVD-R. All existing BD machines can handle both HD and SD, so a 50GB disc could potentially hold around a day's worth of high quality DVD standard video. A big difference between DVD and BD is that as a consequence of the added complexity of and video circuitry within DVD machines, dedicated CD players can easily outperform DVD players playing CDs, ceteris paribus, but BD machines are largely DVD machines, but better, so as long as they support SD and maybe write to DVD too there is no real reason not to buy a BD machine as an upgrade of DVD except for the minor detail of cost. As before, however, for the maximum quality with CDs and SACDs a separate dedicated machine is desirable. I would expect that BD machines will be marketed and sold as an upgraded DVD machine that offers cinema quality pictures and better than cinema quality sound (although the studios won't like it - still, as DTS has developed a new lossless 96kHz/24bit 7.1 codec for cinemas perhaps it will persuade them to upgrade ...

On an appropriate display, true 720p (1280 by 720 pixels progressive, probably using a data rate of at least 10Mbps with MPeg4 FRExt), the improvement over 480i [DVD] is stunning. But true 1080p quality (1920 by 1080 pixels progressive, probably around 16Mbps) on a true 1920 by 1080p display is shockingly good with well recorded material – probably better than quite a few cinemas, where projector focusing is not always the most accurate. Sound quality is a different matter, though. A 25GB disc has enough space for around 2h 40m of 1080p24 (the frame rate of almost all films) with SACD [DSD] quality 5.1 sound, 2h 15m with DSD 14.2 channel sound or 2h with DSD 22.2 channel sound (10 surround, 9 above, 3 below and 2 subwoofers). Whether we get this, of course, depends on the masters and some may consider 22.2 channels over the top – but with so many speakers sharing the acoustic load most can be pretty compact, and amplifiers can be relatively low power. I’d certainly like to hear it – imagine a live concert in 1080p24 and 22.2 lossles audio… But I guess that ultimately the public will decide …

[oxygenuk]

thanks bluwave on taking your time to make a big post like that and reply, much appriciated 8) , so your saying bd will require 1920 x 1080pixel tv to run properly? what kind of tv would this be? plasma or the expensive hdtv im guessing, and do you know any cheap placeas for tv's like that(sony plz) in the uk? comet and rgb direct is quite cheap but i know there has to be much cheaper out there somewhere

[Blu-Wave]

Cheers O2UK,

unfortunately, the vast majority of current displays are not capable of 1920 by 1080p24 and higher resolution. Many claim to be high definition capable or high definition compatible, but have a native resolution that is nowhere near. Fairly common are displays based on 702p panels which can accept a 1080i input. A 1280 by 720 pixel or similar panel which accepts 1080p could still look pretty impressive if the scaling is good, but the one to one pixel mapping of 1920 by 1080 pixel BD-ROM material on to a 1920 by 1080 pixel progressive scan display can make you realise that whilst 720p is wonderful compared to 480i, in the end it's not that special. :roll:

Now that "full" high definition players and pre-recorded material is on its way, many display manufacturers are developing displays at this resolution. Most PDPs and many LCDs have a lower native resolution, but a number of true 1920 by 1080p resolution LCD displays do exist - but they're currently not cheap - I've seen a 57" 1920 by 1080 p60 capable LCD display for around £15,000. But flat panel displays are improving rapidly at the moment, and with all the high definition changes going on too, now is not a good time to buy one if you can avoid it ...

[oxygenuk]

ok thanks, i wasnt really of thinking of buying one for a couple of years yet anyway around the ps3/blu-ray public release in uk :P, but are lcd tv's a good option to go for in the near future? or should i defiently pick a plasma over lcd whichever one id like them to have hdtv support as i think thats wat will be needed judging by wat we been saying :P

[Blu-Wave]

LCD panels tend to be thinner than PDPs, and to use less power. They also tend to offer higher spatial resolution too, and don't suffer from the "burn-in" problem of PDPs. Whilst both have there pros and cons, notably black-level often not being black enough with LCDs, both are improving rapidly. Now that LCD panel are available in similar sizes to PDPs they are starting to sell more quickly than PDPs in the UK, and although OLED panels (which can be much thinner again and use less than half the power of LCDs for similar levels of brightness) are expected to take over from LCDs eventually, two years is not that long to catch the moving target that is LCD. Another display type, the Surface Conduction Electron-Emitter Display [SED] - which is effectively a panel version of the traditional CRT, also shows promise, but large high quality commercial products are probably a few years further away again. Reflective LCDs, which use less power again by relying upon ambient lighting, may make a re-appearance for environmental reasons and outdoor use if nothing else ...

As you say, assuming that the display device is capable of high quality, to get the best results with blue laser based pre-recorded high definition software, progressive scan displays with a native spatial resolution of 1920 by 1080 pixels are required that can support a minimum of 24 frames per second. As it will be difficult to upgrade commercial spatial resolution beyond 1080 for quite some time, Sony and others are looking at the option increasing the frame rate in subsequent releases. IMAX HD, for example, runs at 48fps, whilst UHDV runs at 60fps. This would increase the realism of sports programmes, etc., but means that, ideally, one should go for high definition displays which can properly handle at least 60fps. In practice, such displays are likley to have a response time of around 10ms or less.

[oxygenuk]

so u saying i should maybe wait a few more years instead of a couple would be better? cos at the moment i only have a Bush 21" crt widescreen ops: lol

[Blu-Wave]

Well put it this way; as this is still the bleeding edge for 1080p displays, I wouldn't buy a large display anytime soon unless I didn't mind spending a lot of money on something that is guaranteed to be obselete in months and, more importantly, with a performance that will very quickly be surpassed by newer rivals... At this point in time, apart from interlacing and flicker issues, a high quality CRT is capable of producing better quality images than consumer PDPs and LCDs - 'though with prices in the thousands compared to the hundreds for CRTs, salesmen might tell you otherwise. Professional HD-capable CRTs have even been developed, and high-end consumer ones were even sold in Japan when analogue HDTV was first tried last millennium. :roll:

However, if you can find a high quality 36" 1080p-capable CRT being sold off as the end of the line you might want to grab it, but realistically it is unlikely that true high definition CRT-based displays will be widely marketed now, as the focus (and profits) has moved on the incredible (so the salesmen and ads say) picture quality of flat panel PDPs and LCDs ... :?

[Rob]

The real problem for Blu-Ray and hi-def material in general is whether there will be a sufficient market for it. I can't imagine there are too many people out there with a tv capable of 720p let alone 1080p. Will the average consumer be prepared to replace their main tv sets for a hi-def picture. Part of the reason dvd was such a huge success was that the only requirement on your tv was that it had a scart input. My parents only replace their tvs when they fail completely, every 7-10 years or so. There's no way they're gonna spend thousands to replace a perfectly good set that's only a few years old. It's for this reason I cant' see Blu-Ray being the success that dvd was and is. Ultimately when tvs start to fail, prices for flatscreen hi-def sets drop etc...blu-ray should succeed. Personally, I think the mainstream punter is happy enough with dvd picture quality for the moment. With technolgy moving so quickly at the moment and prices falling drastically, a wait and see attitude would seem the way to go. It's so difficult to work out when to buy.

i.e. Early this year I bought pan dmr60 rec dvd, a few months later the 85 was released with an 80GB HDD and pal/ntsc prog scan. Decided to upgrade to the 85 and gave my brother the 60. IMO it's not worth buying a dvd recorder without a HDD unless you only buy RAM discs. DMR95 model to follow with 160GB HDD. A few months later there's another model announced with HDMI and 250GB HDD. Who knows what's next. Also, recently bought Toshibas' WL46 26" lcd which has 2 RGB, 2 Component and pc inputs, only for a week later to read that there was a new model 48 that featured an HDMI input.

[Blu-Wave]

Good point, Rob - and, of course, many people have 21, 25 or 28 inch 4:3 sets, too. Ironically, many fairly modern home computers running 1280 by 720 pixel displays have the power and screen resolution to support 720p - but typical displays are only 17 or 19 inches across. :roll:

All current Blu-ray machines can record standard definition material too - over a day's worth at high [on DVD terms] quality on the 50GB Panasonic machine, and of course playback DVD and CD. Given the significantly increased processing capability of a Blu-ray machine over a standard DVD player anyway, as a result of the required sixfold increase in resolution over even the best DVD and the more complex codecs employed (not just MPeg2 but probably MPeg4 FRExt too), it may be possible that DVD playback could be further optimised over what is currently typical of even an expensive DVD player, minimising the visible artefacts, etc.. Then again, too much heavy-handed optimisation can make everything start to look as if it's made of plastic ...

LG are due to launch a combined Blu-ray recorder and 200GB hard drive, and Sony have shown off the Type X PC, with a Blu-ray high definition recorder, seven standard definition tuners and 1TB of RAM. A machine situated somewhere between these two examples might do very well. :?

Of course, all things remaining equal, the larger the screen size, the more power a display consumes - 81" Plasmas, for example, use somewhere approaching 1kW to give you the high contrast images you crave. CRTs aren't exactly efficient, but as they don't typically go beyond 36" a modern CRT-based TV will normally consume less than 200W. LCDs use a bit less power than Plasmas, but again, at larger screen sizes there's more to backlight, and power consumption soon overtakes CRTs again. OLED [LEP] displays will probably consume around half the power of typical LCDs, and reflective technologies which exploit ambient light can use far less power again - but don't work too well in a darkened cinema. Perhaps sitting close to a 19" LCD, OLED or Reflective display driven by a reasonably efficient player is the way to go? Using a computer as the source might be all very well, but as most PCs are general purpose, power hungry computing devices, it seem a little pointless when watching films etc. to save a few hundred watts on the display only to throw it away again on the PC. Software dominated firmware might be more flexible, but dedicated hardware can usually be more efficient: abstraction usually costs ...

Talking of progress, one thing that's pretty sure is that 1080p is going to be the home cinema standard for quite a long time to come - 'though maybe not the half century that 480i and 576i have enjoyed. The framerate is likely to increase over time, but spatial resolution will probably not be changed until around 2020 - 'though, as usual, I could be wrong here. Remember that the quality of the best existing PAL and NTSC material has been improving consistently since the fifties, with live broadcasts using high quality cameras capable of being pretty impressive (considering). But if the old standards couldn't deliver at least a good chunk of the cinema experience, DVD wouldn't be the success it is now.

As you say, wait and see isn't a bad idea, and of course caveat emptor, or when it comes to products, cave canem. ... and good luck with your next purchase (no, I didn't mean that tin of beans).

[oxygenuk]

i hope blu-ray will come and do to dvd wat dvd done to vhs, but as you say the mainstream of punters see DVD as there standard

[lifeboat]

"A 50GB disc has enough space for around 2h 40m of 1080p24 (the frame rate of almost all films) with SACD [DSD] quality 5.1 sound."

This seems a bit low. Are you talking about MPeg2 or Mpeg4 FRExt compression?

Eric

[Blu-Wave]

Well spotted, Eric: it's using MPeg4 FRExt at an average video datarate of 15Mbps (hopefully pretty conservative, but I want to see some convincing demos first) and is meant to refer to a 25GB disc - so could of course be doubled for a 50GB disc... I've corrected the error to hopefully avoid further confusion ... :?

[lifeboat]

"Well spotted."

Thanks for the correction!

What is most impressive about Blu-ray to me is that it was obviously designed to have sufficient capacity with MPeg2 encoding. Now that they have decided to go with encoding methods that were invented AFTER they had decided to have a 50GB capacity for a dual layer disk, the capacity of Blu-ray will be quite generous. When the 100GB quad layer discs are released, it will be amazingly generous!

Eric

[Blu-Wave]

Talking of capacity at 1080p24, using FRExt, lossy DD/DTS 5.1 and experts to hand-tune the (variable) bitrate encoding on BD-ROMs (like Microsoft have done with their online 702p24 demos), 50GB should be good for almost 12 hours for pretty reasonable quality 1080p24 viideo combined with pretty poor quality lossy 5.1 sound (either dire, dire or dire to be sure (to be sure). If we go for quality instead, a 50GB disc should be good for around 4 hours of good quality 1080p24 video and lossless DSD 22.2. :shock:

Of course, this is only 1080p24. If we increase the temporal resolution to, say, 96 or 120Hz and the amplitude resolution to 15 bits per colour (ok, 16 if you're may keen on binary), using suitable compression technology a 50GB disc could only hold around 2 hours of 3/16/1080p120 video with lossless DSD 14.2 audio - so that 100GB disc might come in handy after all ... :?

Coincidently, the High Dynamic Range [HDR] display offers a dynamic range of around 60,000:1 - or about 16 bits (remember that CD has a maximum dynamic range, ignoring any noise-shaping and interpolation issues, of 65536:1). Of course, if we start talking about Hexachrome, Octachrome or similar technology, 100GB might seem just a little tiny - and we'll not mention UHDV ...

HDR might potentially offer great quality, but, being self-illuminating, it uses similar amounts of power to a standard LCD panel ('though less than a PDP). Given enough ambient light, a well-designed reflective display - such as reflective LCD or electronic ink - would use much less power than LCDs, OLEDs [LEPs], SEDs [FEDs], CRTs or PDPs - clearly a major plus point from the green point of view ... 8)

[lifeboat]

"using suitable compression technology a 50GB disc could only hold around 2 hours of 3/16/1080p120 video with lossless DSD 14.2 audio - so that 100GB disc might come in handy after all ... :?"

This is what is so wonderful about Blu-ray. Since you could easily hold 40 hours of HDTV content on a double sided quad layer disc, there will be the option to include less content, such as 8 hours of 3/16/1080p120 video with lossless DSD 14.2 audio per 200GB disc. Such quality would never be an option with a HD-DVD disc!

Eric

[Rob]

what's the point having 14.2 or 22.2 audio on blu-ray discs when only 0.00001% of the population will have the set up to take advantage of it?

I'd prefer to see greater screen resolution and frame rates. Perhaps a 72hz or 96hz mode for movies so they can be played at the correct speed without the hassle of 3:2 pull down etc.

[Rimmer]

By 'greater frame rates' do you mean showing 72 or 96 unique frames per second, rather than showing 24 frames 3 or 4 times? Blu-ray/HD-DVD movies will be encoded at 24fps, and the player will output the signal at whatever frame rate the display accepts, e.g. 24p, 24PsF, 60p or 60i.

I don't think there any plans to increase the frame rate in movies in the near future. When cinemas finally go digital it will no longer be necessary to shoot movies at 24p. However, increasing the frame rate will increase costs and cause compatibility issues in countries operating legacy TV systems i.e. most of the world, so I don't see it happening any time soon. Still, we have had 24p since 1926, and that frame rate can't be used forever.