As a follow up to last week’s blog “What is Blu-ray?”, this time let’s look at Blu-ray’s direct competitor, HD DVD. The development of the HD DVD format was lead by Toshiba to be the high definition successor to standard DVD. HD DVD discs can hold about 3 times as much data as a standard DVD, 15gb per layer vs. 4.7gb. The increased data capacity not only allows for a large hi def movie file, but also uncompressed audio, more features and next generation menu functions.
HD DVD resolution is 1080p native. That means that it has 1920(horizontal) x 1080(vertical) progressive (P) lines of resolution. Resolution is a fairly basic concept to understand. More lines = more resolution = sharper image. 1080p as explained above, is the highest hi def format at this point in time that is available to consumers.
Other hi def resolutions include 1920 x 1080i and 1280x720p. These are formats that most HDTVs are built upon, and television is broadcast in. For an explanation on the differences between these formats, visit this hi def reference page.
HD DVD’s can contain up to 7.1 channels of surround sound, using Dolby Digital Plus, lossless formats such as Dolby TruHD, and DTS HD, and other formats used for standard DVDs. The HD DVD format supports encoding up to 24-bit/192 kHz (2 channels), or up to eight channels in 24-bit/96 kHz encoding.
HD DVDs are loaded with interactive features like live menus. So instead of having to interrupt your movie, menus can load while the movie is playing. This allows easy access to jump chapters, replay scenes, and turn on and off movie commentaries. HD DVD players also are internet capable, to allow live updates and upgrades over the web.
HD DVD uses a blue-violet laser to burn the content onto the disc. The improved blue-violet laser technology allows for finer lines of data to be burned in, therefore expanding the disc capacity to hold larger files. Standard DVDs are burned with red lasers, which have a larger light spot area, and therefore not as dense as blue-violet lasers.
HD DVD is not the only high definition disc. Sony’s answer to high definition is the Blu-ray Disc. Blu-ray discs have more capacity than HD DVD, (25gb vs. 15gb), however the use of multiple layers gives both formats the option to exceed the capacity of one layer if needed.
For more information on Blu-ray, read last weeks blog What is Blu-ray?