HD DVD

HD DVD (short for High Density Digital Versatile Disc) is an obsolete high-density optical disc format for storing data and playback of high-definition video. Supported principally by Toshiba, HD DVD was envisioned to be the successor to the standard DVD format, but lost out to Blu-ray, which was supported by Sony and others.

HD DVD employed a blue laser with a shorter wavelength (with the exception of the 3× DVD and HD REC variants), and it stored about 3.2 times as much data per layer as its predecessor (maximum capacity: 15 GB per layer compared to 4.7 GB per layer on a DVD). The format was commercially released in 2006 and fought a protracted format war with its rival, the Blu-ray Disc. Compared to the Blu-ray Disc, the HD DVD was released earlier by a quarter year, featured a lower capacity per layer (compared to 25 GB of Blu-ray), but saved manufacturing costs by allowing existing DVD manufacturing equipment to be repurposed with minimal modifications, and movie playback was not restricted through region codes.

On February 19, 2008, Toshiba abandoned the format, announcing it would no longer manufacture HD DVD players and drives. The HD DVD Promotion Group was dissolved on March 28, 2008.

The HD DVD physical disc specifications (but not the codecs) were used as the basis for the China Blue High-definition Disc (CBHD) formerly called CH-DVD.

Besides recordable and rewritable variants, a HD DVD-RAM variant was proposed as the successor to the DVD-RAM and specifications for it were developed, but the format never reached the market.