The high-definition movie disc battle between HD DVD and Blu-ray Disc can be traced all the way back to 2000, when companies began experimenting with using new blue lasers in optical disc systems.
Because the wavelength of blue light is shorter than that of the red lasers used in DVD, less physical space is needed to record each bit of data and so more information can be crammed onto a DVD-sized disc. This extra space was needed to store the new high-definition video and TV services that were starting to be commercialized around that time.
But what started in 2000 as technical research became a battle between the world's largest electronics companies and movie studios, with the consumer caught in the middle.
Here's a look at the major milestones from the first research:
October 5 -- Sony and Pioneer unveil DVR Blue at Japan's Ceatec show. The format would go on to form the basis for first-generation Blu-ray Disc BD-RE.
November 1 -- Sony announces the development of Ultra Density Optical (UDO), a blue-laser optical disc format proposed to replace magneto-optical discs.
February 19 -- Led by Sony, nine of the world's largest electronics companies unveil plans for Blu-ray Disc.
August 29 -- Toshiba and NEC propose to the DVD Forum the next-generation optical disc format that will become HD DVD.
October 1 -- Prototypes of both formats are unveiled at Japan's Ceatec exhibition. Sony, Panasonic, Sharp, Pioneer and JVC showed prototype Blu-ray Disc recorders while Toshiba showed a prototype under the name Advanced Optical Disc (AOD).
February 13 -- Licensing of Blu-ray Disc begins. Player makers pay US$20,000 to license Blu-ray while the content-protection system license carries a $120,000 annual fee and additional charge of $0.10 per player. Media makers pay $8,000 annually and $0.02 per disc for the copy protection system.
April 7 -- Sony announces its Blu-ray Disc-based Professional Disc format for data archiving applications.
April 10 -- Sony puts on sale in Japan the world's first Blu-ray Disc recorder, the BDZ-S77. It's based on a 23G-byte cartridge version of the BD-RE disc and costs ¥450,000 (US$3,815 at the time). The machine and a later model from Panasonic lack support for prerecorded movies that will launch later and prove an expensive early step into next-generation video.
May 28 -- Mitsubishi Electric joins the Blu-ray Disc group.
January 7 -- Toshiba unveils its first prototype HD DVD player at CES. The player includes backwards compatibility with DVD.
January 12 - Hewlett-Packard and Dell put their support behind Blu-ray Disc.
June 10 -- The first commercial version of HD DVD-ROM is approved by the DVD Forum.
September 21 -- Sony announces the PlayStation 3 will use Blu-ray Disc.
November 29 -- Paramount Pictures, Universal Pictures, Warner Bros. Pictures, HBO and New Line Cinema announce support for HD DVD.
December 9 -- Disney announces support for Blu-ray Disc.
January 7 -- Backers of both formats promise players and movies in North America by the end of the year -- something that never materialized.
March 24 -- Talk and hope of a common format as Ryoji Chubachi, then Sony's president-elect, says: "Listening to the voice of the consumers, having two rival formats is disappointing and we haven't totally given up on the possibility of integration or compromise."
April 21 -- Sony and Toshiba begin discussions on the possibility of a single format. The talks ultimately go nowhere.
August 18 -- Lions Gate Home Entertainment and Universal Music Group decide to back Blu-ray Disc.
September 27 -- Microsoft Corp. and Intel Corp. put their weight behind HD DVD.
October 3 -- Paramount Home Entertainment says it will offer movies on both HD DVD and Blu-ray Disc.
December 16 -- Hewlett-Packard decides to drop exclusive support for Blu-ray Disc and back both formats.
January 4 -- Bill Gates announces at CES that Microsoft will offer an add-on HD DVD drive for the Xbox 360 console.
March 10 -- Blu-ray Disc-supporter LG Electronics surprises the industry with news that it's developing an HD DVD drive.
March 31 -- Toshiba launches the world's first HD DVD player, the HD-XA1. It cost ¥110,000 (US$936 at the time) in Japan.
November 11 -- Sony's PlayStation 3, which packs a Blu-ray Disc drive, goes on sale in Japan.
December 29 -- Hackers report success in breaking through part of the AACS copy protection that's on both HD DVD and Blu-ray Disc.
January 7 -- Seeking to end the battle, LG Electronics unveils a dual-format player, while Warner Bros. shows a prototype disc that holds both an HD DVD and Blu-ray Disc layer so is compatible with players for both formats.
April 17 -- Sales of HD DVD players in North America hit 100,000 since launch.
August 1 -- Microsoft cuts the price of its HD DVD player for the Xbox 360 from US$199 to US$179 and starts offering five free movies.
August 20 -- Paramount and Dreamworks Animation both drop Blu-ray Disc in favor of HD DVD.
September 13 -- Sony says it will use Blu-ray Disc in all high-def video recorders in Japan.
November -- The price of Toshiba HD DVD players drops to US$100 with rebates as the holiday shopping season begins.
November 11 -- Sony begins selling a lower cost version of the PlayStation 3.
January 4 -- Warner Bros. drops its bombshell: it will stop issuing HD DVD movies in the coming months and rely exclusively on Blu-ray Disc. In response the HD DVD Promotion Group cancels its CES news conference.
January 6 -- Akio Ozaka, head of Toshiba America Consumer Products, says at CES: "We remain firm in the belief that HD DVD is the format best suited to the wants and needs of consumers." In response Sony CEO Howard Stringer, with a grin on his face, says "All of us at Sony are feeling blue today."
January 14 -- Toshiba cuts the price of HD DVD players with the HD-A3 seeing a retail price of US$150.
February 11 -- NetFlix and BestBuy say they will phase out HD DVD.
February 15 -- Wal-Mart, the world's largest retailer, says it will phase out HD DVD by June.
February 16 -- Japanese public broadcaster NHK reports Toshiba has halted production of HD DVD players. Several additional local media reports confirm and The Nikkei business daily says Toshiba has decided to stop developing the format any further.