Friday, January 20, 2017
Most Popular
Optical Storage
WEB Reviews
Seagate Enterprise Capacity 3.5 V.3 4TB SAS 6Gb/s HDD Review
OCZ Vector 256GB SSD Review @ Custom PC Review
Gigabyte F2A85XM-D3H
NZXT Phantom 630
Auvio Bluetooth Portable Speaker Review
Corsair H90 CPU Cooler Review
BIOSTAR Hi-Fi Z77X (Intel Z77) Motherboard Review
Noctua NH-L9i Cooler Review on Technic3D
Breaking News
Sharp Establishes New Research and Development Center for Home Appliances in China
Samsung Seeks Arbitration Over LCD Supply Halt
Canon May Invest In Toshiba's Chip Business
Samsung To Explain What Caused The Galaxy Note 7's ban In Press Event
Nintendo's 'Fire Emblem Heroes' Smartphone Game features in-app Purchases
Fujifilm X-T20 Features New 24MP Sensor and 4K Video Capture
Samsung Begins Rollout of Android 7.0 Nougat
European Commission Welcomes Steps Taken by Amazon, Audible and Apple to Improve Competition in Audiobook Distribution
Home > Essays > Optical Storage

Monday, March 15, 2004

1. Page 1

HD-DVD (AOD) Vs Blu-Ray (BD) - Page 1

There has been a lot of discussion lately regarding the two most prominent recording formats being promoted for HDTV use. Looking back at the recent past we could say that the same groups that had fought over DVD-Video formats before it was finally standardized, are still fighting for two new formats. On one side of the fence we have two Japanese giants of the consumer electronics industry, NEC and Toshiba. They have jointly developed the "AOD" (Advanced Optical Disc) format for HDTV recording applications. The main argument for AOD is that it is play-compatible with DVD-Video, and so it is often called "HD-DVD" for that reason. Sony and Philips along with Hitachi, Sharp and Samsung stand on the other side. They are promoting the "BD" format, which is better known as the "Blu-Ray Disc". Both formats initiate evolutionary higher capacities than current DVD-Video.

Structurally, HD-DVD is identical to DVD-Video, employing two 0.60mm thick discs that are bonded together to form the HD disc. It can store 15GB on a single layer DVD. HD-DVD recordings can therefore be replicated on the same equipment and manufacturing infrastructure used to replicate standard DVD-Video recordings. As a result, this minimizes disc production costs.

BD Main Specifications

Data capacity
Single-layer 15GB/sideDual-layer 30GB/side
Single-layer 20GB/sideDual-layer 40GB/side
File format
User bit rate
Disc size
120mm (diagonal), 1.2mm (thickness: 0.6mm x 2)
Laser wavelength
Lens numerical aperture (NA)
Track structure
Land & groove
Signal processing
2/3 conversion

Toshiba and NEC insist that the provided 15GB of capacity is more than adequate for HDTV software applications. The compression algorithms used in HD-DVD are different from those currently in use, so there are claims that the 2/3 conversion could reduce picture quality. On the other hand, the format features the same 0.6 numerical aperture for the object lens and disk structure as the current DVD disk system. The companies stressed the importance of backward compatibility. Taking advantage of this compatibility, NEC has developed a HD DVD drive that employs a single optical head. The head has blue laser and red laser diodes as light sources. However, the lasers share the same object lens. Newly developed ICs handle the physical difference between DVD and HD DVD.

NEC claims the single optical head structure enables production of smaller and thinner HD DVDs at lower cost. Using the single head, NEC developed prototypes of full-and half-height drives that achieved 15 Gbytes for a single-layer ROM disk, 30 Gbytes for a double-layer ROM disk and 20 Gbytes for rewritable disks.

Get RSS feed Easy Print E-Mail this Message

Home | News | All News | Reviews | Articles | Guides | Download | Expert Area | Forum | Site Info
Site best viewed at 1024x768+ - CDRINFO.COM 1998-2017 - All rights reserved -
Privacy policy - Contact Us .