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Red vs. Blue Lasers Complicate DVD's Future
bnavarro writes: "The EE Times is reporting that the DVD Forum's Steering Committee voted this week to approve the use of low-bit-rate compression for high-definition DVD. The DVD Forum's decision, made at a meeting Tuesday (Feb. 26) in Tokyo, to stick with a red-laser-based scheme but switch to low-bit-rate compression, came only a week after nine of the world's biggest electronics companies agreed to promote a blue-laser-based format for next-generation video and computer optical disks."
The color.
Light's color is a function of its frequency, which is inversely proportional to its wavelength. Higher frequency lasers can read pits which are closer together on a disc substrate, allowing them to put more data in the same areal density as lower frequency lasers. Blue is better than red for this purpose.
Alas, it's also harder (read: more expensive) to make blue lasers and the industry has already spent a lot of money on reds, so a blue-laser technology would require the writeoff of existing gear AND the purchase of new. Not an easy sell these days.
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- More compression. Needs
CPU horsepower somewhere (drive? your desktop
CPU?), but CPU horsepower is dirt cheap today.
- Blue lasers. The shorter
your wavelength, the higher your recording
density. But red lasers are widespread and cheap,
while blue lasers in consumer devices are not
all that well understood and there is a very
limited supply at the moment.
If you're in the business of selling blue lasers, of course you want to promote method #2 above. But DVD companies are not in the business of selling blue lasers - they're in the business of selling content.Of course, the decision to not use blue lasers impacts those who use the disks for purposes other than what the DVD companies want. If you want to store data on the disk, the "new" DVD compression doesn't help you any. And if you want to play the new DVD's on your non-DVD-consortium-approved player, the new compression techniques will probably make your attempts more complicated (if not more illegal...)
Can you imagine how confusing Starwars would be if everyone's lasers were the same colour?
...does Joe Six-pack understand the differences between DVD-RW, DVD+RW, DVD-RAM? Do _I_ understand the differences between these formats? Do you? Does the recent el-cheapo DVD player I bought play 2-layer disks? Do I know? WILL I know until I try to put one of them in and find that it won't play?
And now we're going to have TWO competing high-definition DVD formats? And HDTV itself, or do I mean "digital TV," is six or is it eight different formats, which are high-definition, except when they aren't, that is they are high-ER definition but not HIGH definition, only you can't get the high definition, and all the digital TV formats are about to become obsolete...
Anyone who buys ANY HDTV or DVD gear until the dust settles has gotta be nuts.
But you sure have to be amazed at the complexity and ingenuity the industry is using to shoot itself in the foot.
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The point is that while DVD looks great on most standard TV's, HDTV's are another matter. Suddenly you can see lots of compression artifacts. This isn't much of an issue now, but it will be soon enough.
I doubt DVD2, or whatever it will be called, will arrive in the next 5 years and if it does it will be in parallell with the current technology and cater mostly to videophiles and gadget freaks. There's a lot of money to be made from early adopters.
I for one think it's a great idea to decide on a standard before companies start producing their own technologies. That has caused problems again and again. Nice to see people are learning from past mistakes.
What's the difference between blue, red and green lasers?
Green laser pointers use an infra-red laser diode, with a yag crystal to double the frequency. Also, they increase the brightness of the beam by turning in on and off at about a 60/40 duty cycle, while driving the diode at a higher current than it could handle at 100% duty. You can actually see this by moving the dot back and forth quickly - it appears as a dashed line.
They're a neat toy if you've got $400 to burn (last I checked).
I'm not a Microsoft fan, but I've got to admit that idea of downloading a 700 MB .wmv file, burning it to a CD and being able to play it back in my DVD player at DVD quality is quite enticing.
And what on earth makes you think Microsoft's patented DRM will ever allow you to do that? If you want to be able to move your content from medium to medium as you see fit, without restriction, your only real long term hope is to use free software. Of course, if the SSSCA is passed theres a good chance free operating systems, such as FreeBSD and GNU/Linux, will be outlawed as a result.
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Actually, people are buying HDTV for DVD players now. Progressive scanning DVD players, that is. 480p is technically a DTV standard and you can only watch 480p on a DTV or HDTV. Most people who buy HDTV (and I sell a lot of HDTV) buy a progressive scanning DVD players. (you can get one for like $170 now)
Also, the 16x9 formats usually have an enhanced mode for widescreen DVDs. So there's a lot of reason to have an HDTV now and use existing DVD technology. 480p is still pretty sharp compared to the crap we watch over cable.
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Why not make the next shift encompass both technologies?
So you're suggesting they use a purple laser instead?
*ducks*
You can accomplish anything you set your mind to. The impossible just takes a little longer.
I cannot believe these industry "expert" groups. They claim that the main reason for using red lasers is cost. However, they seem to "forget" that using a low-bit rate technology as opposed to a blue laser actually will INCREASE costs since supporting MPEG-4 will require higher processing power, and thus more powerful and more expensive silicon.
BUT most important to consumers is the fact that MPEG-4 compression is just NOT SUITABLE for high-definition content which is meant to be seen on a decently large screen (29 inches and above). MPEG-4 simply produces too many artifacts (even today with low-bit-rate MPEG-2 you can see on cable how dark images in motion seen to leave a "ghost" behind).
So now the REAL REASON why they (the content providers) still want to pursue red-laser: They get to give consumers a low-quality version of the video image!!! By doing this they feel they are protecting their investment, while in reality they are simply giving consumers a low-quality solution.
If and once they provide this stupid red laser approach for high resolution video, what they effectively will have done is invite third parties to come with competing high-quality products (which sadly will probably will never be supported with popular content since there is a monopoly among the content providers and media player producers), OR some hackers will come up with a scheme to rip high-quality video out of HD broadcast (for TV or movie theatres) and distribute it in a competing format themselves over the Internet. In other words, Napster all over again because for the same reason as before: they industry is NOT thinking about what consumers want, and what consumers want is a high-quality display system to match their new TV.
I think it would be great if a high-def DVD format came out in the next year, but it probably won't. Why limit things while still using 9GB DVD's? I don't understand the immediate need. DVD's are doing wonderful, and DVD's in progressive scan look great. We can wait 2 years for blue laser players to become a reality, it won't hurt anything to keep DVD's going longer, people are going to be mad about switching anyway.
The solution of the Red laser camp seems to be better compression (good) better post processing (good) but on the same size disc (bad). Switching formats is a hard transition for everyone, why don't they really switch formats and go for something that will be good enough to last for 10 years. Put blue laser discs, Mpeg 4, and good pre and post processing together and you have something that just may stand the test of time, like CD's. CD's are the first technology that I can remember that could possibly be called 'good enough'. I still want DVD-Audio and SACD to do well, but CD's are the first consumer technology that was really limited by how well they were made and the equipment used to play them back then by the format itself. These technology companies have the chance to do that now, with video, but it doesn't look like they are going to take it.
Look back in history to other formats that were just better use of the same space. SVCD, HDCD (20 bit CD) SVHS, the list goes on. They didn't do too well did they? What makes these companies think that 7 Mbit Mpeg 4 is going to look good enough to make people want to switch? There will compression artifacts all over at high resoltuions. Now 1080p 24fps, that is a beautiful thing and will make people drool.
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Quick corrections (I'm a laser specialist)...
Most of what you said was true a couple years ago, but it's been changing, mostly due to the entertainment industry (get to that in a second...)
Green DPSS lasers (frequency doubled solid-state, as opposed to dye or ion gas lasers) use a very powerful infra-red (either 800 nm or 1.3 um) laser diode, usually 250 mW or higher... fire that at a Yag crystal or rod. The Yag crystal absorbs the infra-red light and lases at 1048 nm. For those who don't know frequencies, 400 is a deep blue, 550 is green, and 650 is deep red. You can see a powerful enough 750 nm beam, but most of the light is invisible.
Anyways, the Yag crystal lases at 1048 and a KDP crystal in the optic resonator doubles the frequency, giving a wavelength of 524 nm. Though there are some loses in the KDP, this is more then made up for by the efficiency of the resonating cavity itself; one of the mirrors is totally reflective to 1048 nm, but totally transparent to 524 nm... any green light passes straight through it.
Most DPSS solutions these days are made for entertainment. Someone figured out that there was a way to take DPSS and make it Continuous Wave (CW), thereby making it suitable for laser light shows. This was more expensive than ion gas lasers at the time (though that's not true any more), but was still attractive because its a much simpler design, has no moving parts, does not require expensive and difficult to maintain cooling, and can be housed in a much smaller box.
As far as cost... if one looks carefully, one can usually find a 5 mW model for between $100-$200. Watts per dollar goes up sharply, I think hitting a peak at 60 mW somewhere around $400-500.
If anyone reading this wants to know more, or acquire one of these... e-mail me at merlin_jim on hotmail.
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