The basics of Blu-Ray
by Dave BrewisGiven that, for all sorts of reasons, there can be only one packaged media format to support HD video releases, the choice will come down to whether Blu-Ray has what it takes to see off its only serious competitor, HD-DVD.
It's not clear yet how the Blu-Ray vs HD-DVD war will resolve itself. Many have compared it to the 'VHS V Betamax' format war of the 1980s which resulted in costly disappointment for those consumers who plumped for a Betamax video recorder.
In terms of comparison the general consensus is that Blu-Ray is technically superior and provides for more video, whereas HD-DVD is more backward compatible and less costly to reproduce.
The Blu-Ray specification was initially announced in February 2002, founded by Sony, Matsushita (Panasonic), Philips, Pioneer, Samsung, Thomson, Sharp, Hitachi and LG. The format has since attracted the committed support of Dell, HP and JVC, and now Apple have announced Blu-Ray support.
The term 'Blu-Ray' is simply derived from the fact that it uses a blue-violet laser as opposed to a red laser found in DVD drives/players.
Blu-Ray, or 'BD' (Blu-Ray Disc) as it's becoming commonly known promises a storage capacity of up to 5 times that of DVD. Single layer BDs will hold 25Gb, and Dual layers will hold 50Gb.
In terms of video content a single layer disc comprising video encoded in MPEG2 will hold around 140 minutes of HD with something sizeable left over for bonuses.
A dual layer disc may hold a 3 hour HD feature plus bonuses, or indeed one 50Gb disc could hold an entire episodic series in SD, thereby slashing production costs for packaged series releases.
Blu-Ray was also designed to meet future consumer demand for recording HDTV programming, and therefore supports direct recording of the MPEG2 (transport stream) used in digital broadcasts.
The BD format supports 3 types of video compression, allowing content makers to choose a compression codec to suit their needs…
Firstly MPEG2, which is currently the compression scheme used in encoding video for DVD. BD players will need to decode MPEG2 in any case in order to offer backward compatibility to consumers who already own a library of DVDs.
Secondly VC-1, which is an extension of Microsoft's WM codec.
Thirdly H-264, sometimes named AVC (Advanced Video Codec). H-264 is actually a flavour of MPEG-4 and is supported by Apple among others.
With Apple's announced support for the Blu-Ray format, we're guaranteed to see G5s with Blu-Ray drives some time soon. And for those of us who create HD content on a mac we're also going to need Tiger (the new mac OS), QuickTime 7, decent H-264 encoding software (an updated Cleaner please!), and an HD version of DVDStudioPro before we're burning HD to Blu-Ray discs. Bring it on!