I remember reading some time ago that HD DVD still used red lasers, whereas BluRay used a blue laser.

Now, I am reading that both use the same, blue, lasers.

I DISTINCTLY remember reading that HD DVD used red lasers, in fact.

Was the spec changed? Or was there a lot of incorrect information out there about HD DVD?

- Tim

Hi and welcome to the forum! There is a possibilty you heard this due to the confusion surrounding the High definition formats.
If you visit this page you can read about EVD and FVD over at HD-DVD.org that describes a method of compression combined with red laser to achive higher capacity.

Then there is the HD-DVD -9 described on that same page to add to the confusion although it does not add capacity at 4.7GB per layer on dual layer discs. Warner Bros came up with this solution to help "backwards compatability and is supposed to be used in conjunctiuon with a blu-ray disc ...somehow. *rolleyes*

But both Blu-ray and HD-DVD "Blue-laser" always used a blue laser.

HD-DVD could mean two things:

1. HD-DVD formerly called AOD or Advanced Optical Disc pioneered by Toshiba and later joined by NEC, Samsung, LG, Microsoft, Intel, etc. Blue laser, of course.

2. HD DVD based on HD MPEG-4 and DVD promoted by Microsoft. Led laser like DVD becase it's physically DVD. What HD-DVD blue laser is to DVD red laser must be like what High-Definition 1080p DVD is to DivX 640*480 DVD.

You have probably heard of VMD (Versatile Multilayer Disc) which is a red-laser HD-DVD format developed by NME ( New Media Enterprises). They claim to be able to produce 20+ GB discs just by adding more layers to the current DVDs. A special chip should control the laser to focus on each layer.

We have seen a pc-demonstration (there was no chip and standalone device available) at the 2005 CeBit but apart from this demo I've never heard or seen something of this technology.