This is a discussion on Facts about Blue Ray Discs by JoeRyan within the Blank Media Discussion forums, part of the DVD Backup Recording forum category; The intent of high definition video was to eliminate or reduce the ...
The intent of high definition video was to eliminate or reduce the artifacts of digital video encoding when seen on large screens (screens over 32"). (Reinforcing motivations were to introduce new hardware and new media once the patents on DVD were running out so that new patents could be issued for new royalty payments. The attraction for the movie industry was the ability to reissue old content another time for more revenue from people who had seen a movie, rented it on cable, bought it on VHS, and bought it again multiple times on DVD issues and reissues. Anti-piracy controls would be also toughened so that it would be very difficult to make copies.)
The Blu-ray camp planned a disc with the same MPEG-2 compression scheme that DVD used, and that meant that a Blu-ray disc would have to hold as much as possible--25GB per layer. (Toshiba and NEC planned on using more advanced codecs such as MPEG-4 so that they only needed 15GB/layer for the same or even better quality than a Blu-ray disc.) In order to get 25GB on a disc, Blu-ray and HD DVD both needed a blue laser diode near the ultra-violet range of light transmission. These diodes are much more expensive and fragile than the ruby-red lasers that DVDs use. But Blu-ray also needed a glass lens that read or recorded extremely close to the surface of the disc in a process called "near-field" playback or recording, unlike the HD DVD system that could use plastic lenses focusing at a distance not unlike that of DVDs or CDs. Near-field reading originally required a cartridge, but DVD-RAM proved that consumers did not like the antiquated look and feel of a disc housing. So an expensive hard-coat was developed for the Blu-ray disc to prevent damage from contact with a pickup unite or debris trapped between the lens and the disc.
Near-field recording also demands the flattest kind of disc possible. If a paper label can cause tilt on a DVD that prevents the accurate focusing on a DVD disc, imagine how much more accurate Blu-ray discs must be with tracks and pits that tiny fractions of those for DVDs. At the time, all these specifications were for Blu-ray's "cutting edge" technology; but whenever there's a cutting edge, someone bleeds. At first it was the manufacturers who were trying to make these discs. Now it's the consumers who are expected to pay $30 for a pressed disc and $10 or so for a recordable disc. (The manufacturing cost of a CD is about 2 cents, less than a jewel case cover. A DVD is less than a dime. Blu-ray is far more expensive--$15 was the figure I remember a few years ago when I was still in the business. If you compare the cost vs the price charged to consumers, I wouldn't expect to see competitive Blu-ray pricing any time soon, no matter how much the costs have declined. They simply are too hard to manufacture.)
HD DVD made some sense in terms of design/cost/functionality. Blu-ray discs are too complex and difficult to manufacture when providing the same functionality. Recordable discs are also extremely expensive, and--at least two years ago--too unstable to consider for archiving anything more than a grocery list. I'm sure things have improved in the last two years, except the prices. The BD design is too complex to bring costs down dramatically unless the volume increases to the levels of DVD production. But that complex design requires a price that is too high to attract the majority of DVD buyers. The Blu-ray group has saddled itself with a cutting edge--an image that would make any horse rider wince.
Last edited by iluvendo; 19-08-2011 at 04:15 AM.