Blu-ray Disc vs HD-DVD

The HD-DVD format, originally called AOD or Advanced Optical Disc, is based on much of today's DVD principles and as a result, suffers from many of its limitations. The format does not provide as big of a technological step as Blu-ray Disc. For example, its pre-recorded capacities are 15 GB for a single-layer disc, or 30 GB for a double-layer disc. Blu-ray Disc provides 67% more capacity per layer at 25 GB for a single-layer and 50GB for a double-layer disc.

Although the HD-DVD format claims it keeps initial investments for disc replicators and media manufacturers as low as possible, they still need to make substantial investments in modifying their production equipment to create HD-DVDs. But what's more important is that HD-DVD can be seen as just a transition technology, with a capacity not sufficient for the long term. It might not offer enough space to hold a High Definition feature along with bonus material in HD quality and additional material that can be revealed upon authorization via a network. When two discs are needed, this will degrade the so-called cost benefit substantially. It is even possible that the HD-DVD specification will be followed up by a renewed version of the technology within a few years, requiring media manufacturers to upgrade their existing production lines again, and consumers to replace their existing playback/recording equipment. On the other hand, the Blu-ray Disc format was designed to be a viable technology for a period of at least 10 to 15 years.

Also on the application layer, the HD-DVD format incorporates many compromises. As the capacity is not likely to be sufficient to encode a full-length feature plus additional bonus materials using the MPEG-2 format, different and stronger encoding formats need to be used. Although Blu-ray Disc offers these advanced codecs as well, the disc has such high capacity that publishers can still use the MPEG-2 encoding format at bitrates up to 54 Mbit/sec. As MPEG-2 is the de-facto standard used in almost any industry involved in digital video (DVD, HDTV, digital broadcast), many authoring solutions are available. Chances are high that a full line MPEG-2 encoding suite is already available, which can be used with no or minor adaptations to encode High Definition content for Blu-ray Disc.

But perhaps the most important factor for the success of Blu-ray Disc is its overwhelming industry-wide support. Almost all consumer electronics companies in the world (combined market share of about 80%) and the world's largest computer companies support the Blu-ray Disc format. This ensures a large selection of Blu-ray Disc players, recorders, PC drives, Blu-ray Disc equipped PCs and blank media will become available. A competing format will not have the manufacturing power to penetrate the market in a level even approaching that of Blu-ray Disc.