Blu-ray vs HD-DVD – the war of the blue laser optical disks

Shuji Nakamura’s blue laser diode exactly fit requirements for next generation DVDs: accurate, reliable, small and affordable both for manufacturing and running costs. It was a brilliant invention, and it offered the opportunity for a single, industry wide high-definition optical storage standard to be agreed upon by the turn of the new millennium. Of course, that is not what happened. Instead, chasing a supposed multi-billion dollar prize, two opposing factions backed mutually incompatible blue laser optical storage solutions: Blu-ray and HD-DVD. There followed years of deadlock which, though Blu-ray finally came out on top, arguably nobody really won, least of all the consumer. At the time specifications for the technologies were first disclosed, a comparison with the current DVD format looked as follows: Format Current generation Next generation DVD playback 4.7GB (single-layer disc); 650nm red laser; MPEG-2 video compression. Blu-ray disc; 27GB (single-layer disc); up to 50GB (dual-layer disc); 405nm blue-violet laser; MPEG-2 video; incompatible with DVD format. DVD recordable 4.7GB (single-layer disc); DVD-R (write-once); DVD-RAM (rewritable); DVD-RW (rewritable); DVD+RW (rewritable); 650nm red laser; MPEG-2 video compression. HD-DVD disc; 9GB (dual layer disc); 405nm blue-violet laser; MPEG-4 or improved MPEG-2 with extensive pre- and post-processing; compatible with DVD format. Initial indications were that DVD Forum member Warner Bros. and other movie content production companies were firmly in the HD-DVD camp, since it would allow Hollywood studios to repurpose their content one more time without having first to incur high investment costs in transitioning to brand-new replication equipment. In effect, the similarity between HD-DVD and the then current DVD manufacturing processes made it much less expensive to adapt production lines...

HD-DVD (High Definition Digital Versatile Disk) – blue laser optical disk

Despite High Definition Digital Versatile Disc HD-DVD) being the original DVD Forum approved successor to the DVD format, it was ultimately doomed, eventually consigned to history by the rival Blu-ray Disk (BD) technology. Originally called Advanced Optical Disc (AOD), the technology’s basic format specifications were developed and proposed jointly by Toshiba and NEC. These define an optical disc that uses state-of-the-art blue-violet laser technology to enable extremely large-capacity recordings and high speed data transfer rates. Although primarily designed as a high-definition consumer video recording format, its very high storage capacities and high-speed data transfer rates also make HD-DVD suitable for storage libraries and ultimately other applications. An HD-DVD disc has the same physical size as a DVD, but has higher data and track densities that give it between roughly three to six times the storage capacity of a standard 4.7GB DVD-R. This feat is made possible using a 405nm blue-violet laser, actually violet-purple, and an optical pickup head with a 0.65 numerical aperture (NA) lens. Because a blue-violet light laser has a shorter wavelength than the red light’s 650nm, used in CD and DVD systems, it allows the laser beam to make a smaller spot on the disc surface. With each bit of data taking up less space on the disc, more data can be stored on a 4.7in disc. (For comparison with the light wavelengths depicted above, a human hair averages around 100,000nm thick). The HD-DVD format offered significantly less capacity than the Blu-ray technology, using low-bit-rate encoding technology such as MPEG-4 to store 9GB of high-definition video content onto a dual-layer DVD. However, HD-DVD’s big advantage over...

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