Comparison of high definition optical disc formats

This article is about comparative HD optical disc formats. For a history of the Blu-ray/HD DVD format war, see High definition optical disc format war.

This article compares the technical specifications of multiple high definition formats, including HD DVD and Blu-ray Disc; two mutually incompatible, high definition optical disc formats that, beginning in 2006, attempted to improve upon and eventually replace the DVD standard. The two formats remained in a format war until February 19, 2008 when Toshiba, HD DVD's creator, announced plans to cease development, manufacturing and marketing of HD DVD players and recorders.^[1]

Other high-definition optical disc formats were attempted, including the multi-layered red-laser Versatile Multilayer Disc and a Chinese made format called EVD. Both appear to have been abandoned^{[citation needed]}by their respective developers.

Technical details

A Table Comparing the High-definition Optical Media Formats
DVD included for comparison
Mandatory codecs must be supported by the player. Each disc must use one or more of the mandatory codecs.

			Blu-ray Disc	HD DVD	CBHD (CH-DVD)	AVCHD	AVCREC	DVD	MUSE LD
Laser wavelength			405 nm (blue-violet laser)			650 nm (red laser)
Numerical aperture			0.85	0.65		0.6			Unknown
Storage capacity (single side)		per layer/maximum	25/50 GB[a]	15/30 GB[a]		1.4/2.6 GB (8 cm DVD), 4.7/8.5 GB (12 cm DVD)	4.7/8.5 GB		30 cm, 60 min per side
Maximum bitrate	Raw data transfer		53.95 Mbit/s	36.55 Mbit/s		18 Mbit/s		11.08 Mbit/s	Unknown
	Audio+Video+Subtitles		48.0 Mbit/s	30.24 Mbit/s		Unknown		10.08 Mbit/s	Unknown
	Video		40.0 Mbit/s	29.4 Mbit/s		Unknown		9.8 Mbit/s	Unknown
Mandatory video codecs			H.264/MPEG-4 AVC / VC-1 / MPEG-2		China's AVS / H.264/MPEG-4 AVC / VC-1 / MPEG-2	H.264/MPEG-4 AVC	H.264/MPEG-4 AVC MPEG-2	MPEG-1 / MPEG-2	MUSE
Audio codecs (maximum data rates shown)	lossy	Dolby Digital	Mandatory 640 kbit/s	Mandatory 504 kbit/s [1]		Mandatory 64-640 kbit/s		Mandatory 448 kbit/s	Unknown
		DTS	Mandatory 1.5 Mbit/s		Unknown	N/A		Optional 1.5 Mbit/s	Unknown
		Dolby Digital Plus[d]	Optional 1.7 Mbit/s	Mandatory 3.0 Mbit/s		N/A		N/A	Unknown
		DTS-HD High Resolution	Optional 6.0 Mbit/s	Optional 3.0 Mbit/s	Unknown	N/A		N/A	N/A
	lossless	Linear PCM[h]	Mandatory			Optional			(B Mode) 2 channel PCM
		Dolby TrueHD[h]	Optional 18 Mbit/s	Mandatory 18 Mbit/s		N/A		N/A	Unknown
		DTS-HD Master Audio[h]	Optional 24.5 Mbit/s	Optional 18 Mbit/s	Unknown	N/A		N/A	N/A
Secondary video decoder (PiP)			Mandatory for Bonus View players[c]	Mandatory	Unknown	Unknown		N/A	N/A
Secondary audio decoder			Mandatory for Bonus View players[c]	Mandatory	Unknown	Unknown		Optional	N/A
Interactivity			BDMV and Blu-ray Disc Java	Standard Content and Advanced Content	CETC	Rudimentary			N/A
Internet support			Mandatory for BD-Live players	Mandatory	Unknown	N/A
Video resolution (maximum)			1920×1080					720×480 (NTSC) 720×576 (PAL)	1125 interlaced lines 1035 lines displayed
Frame rates at maximum resolution			24p, 50/60i[2][g]	24/25/30p, 50/60i		24p, 50/60i	Unknown	24/25/30p[g] 50/60i	60i
Digital Rights Management			AACS-128bit / BD+ / ROM-Mark	AACS-128bit	AACS-128bit / DKAA	None (Not intended for prerecorded content)		CSS 40-bit	None
Region codes			Three region codes[f]	None	Unknown	None		8 regions (6 commercial)	None
Hardcoating of disc			Mandatory	Optional					Unknown

^ a These maximum storage capacities apply to currently released media as of July 2008. The DVD Forum has approved a triple-layer version of HD DVD that would have a capacity of up to 51 GB, and Hitachi has proposed a modified Blu-ray version that would support a capacity of up to 100 GB. However, neither has yet been mass-produced or released.
^ b All HD DVD players are required to decode the two primary channels (left and right) of any Dolby TrueHD track;^[3][4] however, every Toshiba made stand alone HD DVD player released thus far decodes 5.1 channels of TrueHD.
^ c On November 1, 2007 Secondary video and audio decoder became mandatory for new Blu-ray Disc players when the Bonus View requirement came into effect. However, players introduced to the market before this date can continue to be sold without Bonus View.
^ d There are some differences in the implementation of Dolby Digital Plus (DD+) on the two formats. On Blu-ray Disc, DD+ can only be used to extend a primary Dolby Digital (DD) 5.1 audiotrack. In this method 640 kbit/s is allocated to the primary DD 5.1 audiotrack (which is independently playable on players that do not support DD+), and up to 1 Mbit/s is allocated for the DD+ extension. The DD+ extension is used to replace the rear channels of the DD track with higher fidelity versions, along with adding additional channels for 6.1/7.1 audiotracks. On HD DVD, DD+ is used to encode all channels (up to 7.1), and no legacy DD track is required since all HD DVD players are required to decode DD+.
^ e On PAL DVDs, 24 frame per second content is stored as 50 interlaced frames per second and gets replayed 4% faster. This process can be reversed to retrieve the original 24 frame per second content. On NTSC DVDs, 24 frame per second content is stored as 60 interlaced frames per second using a process called 3:2 pulldown, which if done properly can also be reversed.
^ f As of July 2008, about 66.7% of Blu-ray discs are region free and 33.3% use region codes.^[5]
^ g DVD supports any valid MPEG-2 refresh rate as long as it is packaged with metadata converting it to 576i50 or 480i60, This metadata takes the form of REPEAT_FIRST_FIELD instructions embedded in the MPEG-2 stream itself, and is a part of the MPEG-2 standard. HDDVD is the only high-def disk format that can decode 1080p25 and 1080p30 while Blu-ray and HDDVD can both decode 1080p24. 1080p25 and 1080p30 content can only be presented on Blu-ray as 1080i50 and 1080i60 respectfully.
^ h Linear PCM is the only lossless audio codec that is mandatory for both HDDVD and Blu-ray disk players, only HDDVD players are required to decode two lossless sound formats and those are Linear PCM and Dolby TrueHD. Dolby TrueHD and DTS-HD Master Audio have become sound format of choice for many studios on their Blu-ray titles but ever since Blu-ray won the format war, it has not become clear if the they are now Mandatory for all new Blu-ray disk players since the end of the format war.

Capacity/codecs

Blu-ray Disc has a higher maximum disc capacity than HD DVD (50 GB vs. 30 GB for a double layered disc). In September 2007 the DVD Forum approved a preliminary specification for the triple-layer 51GB HD DVD (ROM only) disc though Toshiba never stated whether it was compatible with existing HD DVD players. In September 2006 TDK announced a prototype Blu-ray Disc with a capacity of 200GB.^[6] TDK was also the first to develop a Blu-ray prototype with a capacity of 100GB in May 2005.^[7] In October 2007 Hitachi developed a Blu-ray prototype with a capacity of 100GB. Hitachi has stated that current Blu-ray drives would only require a few firmware updates in order to play the disc.^[8]

The first 50 GB dual-layer Blu-ray Disc release was the movie Click, which was released on October 10, 2006. As of July 2008, over 95% of Blu-ray movies/games are published on 50 GB dual layer discs with the remainder on 25 GB discs.^[5] 85% of HD DVD movies are published on 30 GB dual layer discs, with the remainder on 15 GB discs.^[9][10]

The choice of video compression technology (codec) complicates any comparison of the formats. Blu-ray Disc and HD DVD both support the same three video compression standards: MPEG-2, VC-1 and AVC, each of which exhibits different bitrate/noise-ratio curves, visual impairments/artifacts, and encoder maturity. Initial Blu-ray Disc titles often used MPEG-2 video, which requires the highest average bitrate and thus the most space, to match the picture quality of the other two video codecs. As of July 2008 over 70% of Blu-ray Disc titles have been authored with the newer compression standards: AVC and VC-1.^[5] HD DVD titles have used VC-1 and AVC almost exclusively since the format's introduction. Warner Bros., which used to release movies in both formats prior to June 1, 2007, often used the same encode (with VC-1 codec) for both Blu-ray Disc and HD DVD, with identical results. In contrast, Paramount used different encodings: initially MPEG-2 for early Blu-ray Disc releases, VC-1 for early HD DVD releases, and eventually AVC for both formats.

Whilst the two formats support similar audio codecs, their usage varies. Most titles released on the Blu-ray format include Dolby Digital tracks for each language in the region, a DTS-HD Master Audio track for all 20th Century Fox and Sony Pictures and many upcoming Universal titles, Dolby TrueHD for Disney and Sony Pictures and some Paramount and Warner titles, and for many Blu-ray titles a Linear PCM track for the primary language.^[5] On the other hand, most titles released on the HD DVD format include Dolby Digital Plus tracks for each language in the region, and some also include a Dolby TrueHD track for the primary language.

Interactivity

Both Blu-ray Disc and HD DVD have two main options for interactivity (on-screen menus, bonus features, etc.).

Blu-ray's basic mode is known as HDMV or BDMV ("High Definition Movie Mode" or "Blu-ray Disc Movie Mode"), whilst HD DVD's is known as "Standard Content". Both offer modest upgrades from standard DVD, such as the use of more buttons on-screen, a larger colour palette, and expanded programming environment. BDMV is more powerful than Standard Content, and has been used on many Blu-ray disc titles. Standard Content has been used less on HD DVDs^{[citation needed]}. HD DVD's Standard Content is a minor change from standard DVD's subpicture technology, while Blu-ray's BDMV is completely new. This makes transitioning from standard DVD to Standard Content HD DVD relatively simple^{[citation needed]} -- for example, Apple's DVD Studio Pro has supported authoring Standard Content since version 4.0.3.^{[citation needed]} For more advanced interactivity Blu-ray disc supports BD-J while HD DVD supports Advanced Content.

Disc construction

Blu-ray Discs contain their data relatively close to the surface (less than 0.1 mm) which combined with the smaller spot size presents a problem when the surface is scratched as data would be destroyed. To overcome this, TDK, Sony, and Panasonic each have developed a proprietary scratch resistant surface coating. TDK trademarked theirs as Durabis, which has withstood direct abrasion by steel wool and marring with markers in tests.^[11]

HD DVD uses traditional material and has the same scratch and surface characteristics of a regular DVD. The data is at the same depth (0.6 mm) as DVD as to minimize damage from scratching. As with DVD the construction of the HD DVD allows for a second side of either HD DVD or DVD.

A study performed by Home Media Magazine (August 5, 2007) concluded that HD DVDs and Blu-ray discs are essentially equal in production cost. Quotes from several disc manufacturers for 25,000 units of HD DVDs and Blu-rays revealed a price differential of only 5-10 cents. (Lowest price: 90 cents versus 100 cents. Highest price: $1.45 versus $1.50.)^[12] Another study performed by Wesley Tech (February 9, 2007) arrived at a similar conclusion. Quotes for 10,000 discs show that a 15 gigabyte HD DVD costs $11,500 total, and 25 gigabyte Blu-ray or a 30 gigabyte HD DVD costs $13,000 total.^[13] For larger quantities of 100,000 units, the 30 gigabyte HD DVD was more expensive than the 25 gigabyte Blu-ray ($1.55 versus $1.49).^[14]

Hybrid discs

At the January 8, 2007 Consumer Electronics Show, Warner Bros. introduced a hybrid technology, Total HD, that would reportedly support both formats on a single disc.^[15] The new discs would overlay the Blu-ray and HD DVD layers, placing them respectively 0.1 mm and 0.5 mm beneath the surface. The Blu-ray top layer would act as a two-way mirror, reflecting just enough light for a Blu-ray reader to read and an HD DVD player to ignore. But the following September, Warner President Ron Sanders said that the technology was on hold due to Warner being the only one that would publish on it.^[16]

On January 4, 2008, Warner Bros. announced that it would support the Blu-ray format exclusively beginning on June 1, 2008. This news, along with the end of the format war, would indicate that the hybrid discs would not be put into production.

Copy protection

The primary copy protection system used on both formats is the Advanced Access Content System (AACS). Other copy protection systems include:

Blu-ray Disc	HD DVD
HDCP encrypted digital output ROM-Mark watermarking technology (physical layer) BD dynamic crypto (BD+) Cinavia Digital Mark	HDCP encrypted digital output

Region coding

Main article: Blu-ray Disc - Region codes

The Blu-ray specification and all currently available players support region coding. As of July 2008 about 66.7% of Blu-ray Disc titles are region-free and 33.3% use region codes.^[5]

The HD DVD specification has no region coding, so an HD DVD from anywhere in the world will work in any player. The DVD Forum's steering committee has discussed a request from Disney to add it, but many of the 20 companies on the committee actively oppose it.^[17]

Some film titles that are exclusive to Blu-ray in the United States such as Sony's xXx, Fox's Fantastic Four: Rise of the Silver Surfer and The Prestige, are available on HD DVD in other countries due to different distribution agreements (in fact, The Prestige was released outside the US by once format-neutral studio Warner Bros. Pictures). Since there is no region coding in HD DVDs, there are no restrictions playing foreign-bought HD DVDs in an HD DVD player.^[18]

References

1. ^ "Toshiba Announces Discontinuation of HD DVD Businesses". Toshiba Press Department. 2008-02-19. http://www.toshiba.co.jp/about/press/2008_02/pr1903.htm. Retrieved 2008-02-19. 
2. ^ http://www.blu-raydisc.com/Assets/Downloadablefile/2b_bdrom_audiovisualapplication_0305-12955-15269.pdf
3. ^ HD DVD Promotion Group
4. ^ DVD Forum.org HD DVD Technology
5. ^ ^{a b c d e} "Blu-ray Disc Statistics". http://www.blu-raystats.com/Stats/Stats.php. Retrieved 2008-07-04. 
6. ^ "TDK Develops Blu-ray Media with 200GB Capacity". http://www.blu-ray.com/news/?id=94. 
7. ^ "Develops 2X, 100GB Blu-ray Disc Prototype". http://www.blu-ray.com/news/?id=46TDK. 
8. ^ "Hitachi Develops BD-100". http://www.blu-ray.com/news/?id=559. 
9. ^ Frequently updated list of historical release dates and disc capacities, HD DVD NEWS, High-Def Digest, 15 April 2007
10. ^ HD DVD Statistics, HDDVDstats.com, 15 January 2008
11. ^ "Durabis durability". http://www.engadget.com/2007/01/19/tdks-durabis-2-coating-protects-200gb-blu-ray-discs/. 
12. ^ "Indies wait for HD - Page 1 - lists bulk prices for blank discs". http://www.nxtbook.com/nxtbooks/questex/hom080507/index.php. 
13. ^ "Blu-ray vs HD DVD replication costs analyzed again - Lists 10,000-quantity prices for blank discs". http://wesleytech.com/blu-ray-vs-hd-dvd-replication-costs-analyzed-again/113/. 
14. ^ "Blu-ray replication vs HD DVD replication costs revealed - Lists 100,000-quantity prices for blank discs". http://wesleytech.com/blu-ray-vs-hd-dvd-replication-costs-revealed/111/. 
15. ^ Shilov, Anton (2007-01-04). "Warner’s Total HD to End Blu-ray Vs. HD DVD War". X-bit labs. http://www.xbitlabs.com/news/multimedia/display/20070104060353.html. Retrieved 2007-01-04. 
16. ^ "Warner Remains Loyal To Dual HD Formats". TWICE. 2007-09-12. http://www.twice.com/article/CA6477849.html. Retrieved 2008-04-25. 
17. ^ "Microsoft: why HD DVD can beat Blu-ray". 2007-04-03. http://www.tech.co.uk/home-entertainment/video/dvd-hdd-players-and-receivers/blu-ray-and-hd-dvd/features/microsoft-why-hd-dvd-can-beat-blu-ray. Retrieved 2007-11-13. 
18. ^ Sarah McBride (2007-10-18). "Blu-ray vs. HD DVD: a Solution Abroad". Wall Street Journal online. http://online.wsj.com/article/SB119267051987662923.html?mod=googlenews_wsj. Retrieved 2007-11-15. 

External links

Blu-ray portal

• Blu-ray vs. HD DVD article by cdfreaks.com