The Road to the Xbox 360 HD DVD Player

Following is an extract from the Xbox Team development blog where they share with us the build up to their own "Emergence Day" - the launch of the Xbox 360 HD DVD player.

What takes 4.7 million lines of code, partner teams from all over Microsoft, and millions of dollars to create?  The Xbox 360 system software?  Nope.  This is just the HD DVD player.

The Xbox platform team (us) is experiencing its own emergence day as of late; we've been hard at work for the past 8 months straight bringing the fall system update to fruition.  I haven't even posted since August.  Daryl's already gone over a lot of the features and changes that are in this release.  I've personally been working on the Xbox 360 HD DVD player (which, by the way, reached the #1 best seller slot on Amazon.com's video games category) and I thought I'd go over some of the technical difficulties it takes to bring HD DVD to market.

There's a perception that HD DVD is just DVD with HD content, but once you look at things more closely, it's clear that HD DVD is a different beast altogether.  The Xbox platform team became serious about HD DVD last year, when Microsoft as a company threw its endorsement behind the standard.

The Xbox 360 HD DVD Player, for the most part, is an entirely software based implementation.  Other players on the market have specialized chips (called DSPs) that decode things like H.264, MPEG, VC1, DTS, Dolby Digital, and other codecs.  Much like how backwards compatibility for Xbox 1 works on Xbox 360, the heavy parts of HD DVD are all done on Xbox 360's triple-core CPU.

If DVD is an audio/video pipeline with some navigation data (go to the menu, start playing, etc.), HD DVD can be considered a runtime environment where audio/video playback is just one major feature.  So let's break down that 4.7 million lines of code.  I don't have the numbers for each component, but each of these is a very significant chunk:

• Video Codecs: H.264, MPEG-2, VC1
• Audio Codecs: Dolby Digital+, DTS, TrueHD, LPCM, MPEG
• HDi: The HD DVD runtime engine.
• GDI: Drawing stuff like menus
• AACS: Cryptography/DRM stuff
• MF: Audio/Video pipeline

Read more at the Xbox Team blog here.