hardware difference between blu and hd-dvd?

[frank_t]

software/firmware aside, what is the physical difference that prevents an HD-DVD drive from playing blu and a blu drive from playing HD-DVD?

just curious how far apart these two formats really are.

[yeslek]

isnt it the way in which its burnt to a disc

both blu lasers but HD are burnt at a differant angle or something (i'm not too sure)
a more techhy head will no doubt explain properly

[w_tanoto]

blu-ray has 2 lasers, hd dvd only has one. I can show you the picture

[Lambchop]

I think it is the aperture of the laser, (off the top of my head.) They are both blue lasers. The information on Bd is written much closer to the surface of the disc than Hd dvds & dvds. But do correct me if I'm wrong.

[Blue]

Yeslek's answer is close enough. The technical answer is the NA (Numerical Aperture) or how the lens focuses the laser beam on the disc. Before anyone starts, no amount of firmware updates can change the lens's NA. It can't be done, so once a Blu-ray player always a Blu-ray player, once a HD-DVD player always a just "good enough" optical media player.

[dialog_gvf]

Originally Posted by frank_t

software/firmware aside, what is the physical difference that prevents an HD-DVD drive from playing blu and a blu drive from playing HD-DVD?

just curious how far apart these two formats really are.

- The depth of the recorded layers. Single layers are at 0.1 mm for BD and 0.6 mm for DVD/HD DVD
- The numerical apature of the lens is 0.8 for BD and 0.65 for HD DVD
- The geometry of the pits on the surface is different (BD is much denser)
- The data modulations are different (the bit representation, error correction codes, and the PRML method used by the drive)

Gary

[w_tanoto]

left: HD DVD, right: BD

[frank_t]

Originally Posted by Blue

Yeslek's answer is close enough. The technical answer is the NA (Numerical Aperture) or how the lens focuses the laser beam on the disc. Before anyone starts, no amount of firmware updates can change the lens's NA. It can't be done, so once a Blu-ray player always a Blu-ray player, once a HD-DVD player always a just "good enough" optical media player.

Thanks.

Was wondering more along the lines of what drives the high cost of dual format players. Obviously the drive is capable of "adjusting" to accommodate either format.

I suspect it's not hardware but licensing and software.

[WickyWoo]

Yes it is licensing costs, software, R&D, lower demand, and not wishing to cannibalize their Blu sales.

People who want both will pay for both,simple as that. You make up for the low demand with higher prices

[Anthony P]

blu-ray has 2 lasers, hd dvd only has one. I can show you the picture

no, what you are thinking of is OPU and lenses. But even that is not true for example the PS3 has always just had one

[nails]

Originally Posted by w_tanoto

left: HD DVD, right: BD

Wow that right there is exactly why blu-ray costs more than HD DVD lol I didn't even know that.

[mystiksuicide]

I wasn't aware of the differences but it's great to know. Also if I understood your explanation blu is a better for reading the PQ and AQ the disc has stored

[Iceman_II]

Originally Posted by frank_t

Thanks.

Was wondering more along the lines of what drives the high cost of dual format players. Obviously the drive is capable of "adjusting" to accommodate either format.

I suspect it's not hardware but licensing and software.

Close... "adjusting" would mean focusing to a different NA... and if it can focus, it can easily become "unfocused" I believe the dual format players have two separate lasers and pickups