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Chapter 12 - High Definition DVD
HD DVD and Blu-ray Formats
Background
Although this report covers the Hi-Def DVD subject comprehensively, please also
consult the Hi-Def DVD section within the 2005 HDTV Technology Report for
information before February 2005, and a complete background of formats, players,
discs, audio/video codecs, etc.
I include below a summary of the basic background to facilitate the reading of this
report, as follows:
The HD DVD disc is based in two 0.6 millimeter bonded discs (like regular DVD), with
a capacity of 30GB dual layer (15GB single layer), which Toshiba says can hold up to
8 hours of HD. The Blu-ray disc has a capacity of 50GB dual-layer (25GB single
layer) and is constructed with a 0.1 mm optical transmittance protection layer above
the 1.1 mm substrate. Both competing formats use blue laser technology.
Both formats selected MPEG-2, MPEG-4 H.264, and WMV-9 VC1 as mandatory video
codecs and all players must be able to decode them to be compliant. Discs would
have to be encoded with at least one of them, at the choice of the content provider.
Triple and four layer discs for longer duration were also invented, as well as hybrid
discs that would hold the HD and DVD version of a movie in the same disc, which
would help consumers, replication, and distribution channels alike.
In October 2004, the DVD Forum and the Blu-ray Disc Association approved
mandatory and optional audio formats for both Hi-Def DVD standards. Both groups
approved Dolby Digital 5.1 and DTS 5.1 as mandatory HD player formats, which also
ensure the audio playability of 5.1 multi-channel DVDs when played on HD players.
At least one of the audio formats must be included on a pre-recorded disc, at the
choice of the content provider.
In the 4th quarter of 2004, Dolby announced its Dolby Digital Plus lossy format, a
higher-bit rate enhancement to Dolby's existing AC-3 lossy format (refer to the
Glossary for details). DTS also announced their DTS ++ (later named DTS-HD), and
later further extended to DTS Master Audio naming convention, capable of higher bit
rates, and lossless.
At that time, both Hi-Def DVD format groups declared optional the player’s ability of
decoding the 6.1 channels of DTS. On September 23, 2004, Dolby announced that
the DVD Forum decided to include as mandatory audio formats for HD DVD at Dolby
Digital Plus and MLP Lossless based Dolby True HD. MLP is the core audio
technology behind multichannel DVD-Audio.
During 2005/6 more multi-channel audio format decisions and announcements were
made regarding their mandatory/optional application to both Hi-def DVD formats.
Please consult the details on the Glossary or on the Multi-channel Audio section.
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