Published on 19th October 2006 by
Codecs are compression schemes that can be used to store audio and video information on a disc. The BD-ROM specification places requirements on both hardware decoders (players) and the movie-software (content).
For video, ISO MPEG-2, H.264/AVC, and SMPTE VC-1 are player-mandatory. (This means all BD-ROM players must be capable of decoding all three video codecs.) MPEG-2 video allows decoder backward compatibility for DVDs. H.264, sometimes called MPEG-4 part 10, is a more recent video codec developed jointly by the same organization (ISO/IEC) as MPEG-2. VC-1 is a competing MPEG-4 derivative codec proposed by Microsoft (based on Microsoft's previous work in Windows Media 9). BD-ROM titles with video must store video using one of the three mandatory codecs (multiple codecs on a single title are legal).
Initial versions of Sony's Blu-ray Disc-authoring software only included support for MPEG-2 video, so the initial Blu-ray Discs were forced to use MPEG-2 rather than the newer codecs, VC-1 and H.264. An upgrade was subsequently released supporting the newer compression methods so the second wave of Blu-ray Disc titles were able to make use of this. The choice of codecs affects disc cost (due to related licensing/royalty payments) as well as program capacity. The two more advanced video codecs can typically achieve twice the video runtime of MPEG-2. When using MPEG-2, quality considerations would limit the publisher to around two hours of high-definition content on a single-layer (25 GB) BD-ROM.
For audio, BD-ROM players are required to support Dolby Digital AC-3, DTS, and linear PCM (up to 7.1 channels). Dolby Digital Plus, and lossless formats Dolby TrueHD and DTS HD are player optional. BD-ROM titles must use one of mandatory audiotracks for the primary soundtrack (linear PCM 5.1, Dolby Digital 5.1 or DTS 5.1.). A secondary audiotrack, if present, may use any of the mandatory or optional codecs. For lossless audio in movies in the PCM, Dolby TrueHD or DTS-HD formats, Blu-ray Discs support encoding in up to 24-bit/192 kHz for up to six channels, or up to eight channels of up to 24-bit/96 kHz encoding. For reference, even new big-budget Hollywood films are mastered in only 24-bit/48 kHz, with 16-bit/48 kHz being common for ordinary films.
For users recording digital television broadcasts, the Blu-ray Disc's baseline datarate of 36 Mbit/s is more than adequate to record high-definition broadcasts. Support for new codecs will evolve as they are encapsulated by broadcasters into their MPEG-2 transport streams, and consumer set-top boxes capable of decoding them are rolled out. For Blu-ray Disc movies the maximum transfer rate is 54 Mbit/s (1.5x) for the combined audio and video payload, of which a maximum of 40 Mbit/s can be dedicated to video data. This compares favorably to the maximum of 36.55 Mbit/s in HD-DVD movies for audio and video data. 
Originally Posted by Lazlow£800? For a media centre, with BD, that's not too bad. And for a first generation piece of equipment - it looks like they've got most aspects of it right...
Originally Posted by mclean007Nah mate, £800 EXTRA over the non-BD version of the same HTPC. The all-up price is a shade under £1800 inc VAT.
Originally Posted by DougEdeyDon't know if I missed it, but what does that sticker say just under the drive?
ANd I thought BD didn't use MPEG-2 anymore?
Originally Posted by LazlowOooooooooooh, then in that case it's too pricey for most to even consider. I was going by the £800 comment on the last page of the article.
Originally Posted by JADSI think ignoring both formats until the manufacturers come up with one better standard would be good idea :)
Just need the papers to throw in some hysteria about the formats, present it to the general populace and you have two completely dead formats :)
Maybe that both HD-DVD and Blu-Ray give off harmful levels of Theta radiation that will slowly kill kids as they watch their movies? Remember it doesn't matter if it is true if it makes a good story :D
Originally Posted by mclean007It's pretty poor form that Vista may only support Blu-Ray within its media center component by launching some kind of third party player. You'd think native support would be the obvious way to go, or at least some kind of add-on that integrates into media center for a seamless experience?! If it natively supports HD-DVD but not Blu-Ray, that would be a pretty significant factor for a lot of people.
Originally Posted by CthippoSo basically, HDCP is a mess like we all thought it would be. woo hoo Sony :(
Originally Posted by BindibadgiThen Microsoft would have to pay a lisence to Dolby and those who hold the patents to the MPEG compression technology. They didn't in XP either, it can't play DVDs without 3rd party software.
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