HD-DVD versus Bluray: Microsoft employees weigh the pros and cons

Sunday evening, Xbox Live Director of Programming Larry Hryb’s (aka Major Nelson) podcast featured a lengthly comparison of the next-generation disc formats, HD-DVD and Bluray. Appearing as his guests and topical experts were Amir Majidimehr, corporate vice president of the Consumer Media Technology Group at Microsoft, and Kevin Collins, Senior Program Manager at Microsoft.

Fair disclaimer: Microsoft today is firmly in the pro HD-DVD camp, but as Amir points out during the discussion, MS maintained neutrality in the format war for about two years before committing to HD-DVD in September of 2005. Also note that I will also be reprinting the points made during the podcast verbatim – meaning they’re not my words, but theirs – don’t shoot the messenger.

Disc Manufacturing
Bluray: Recording surface very close to the top layer of the disc – a 1.1mm substrate followed by the data layer, and a 0.1mm protective cover. High reliability of manufacturing thus becomes an issue as Bluray disc manufacturers try to apply a very thin protective layer and inevitably contaminate the data layer of a number of discs. Evidence of manufacturing issues? Current Bluray discs are shipping at half-capacity of what was originally announced; 25GB instead of 50GB per disc.

HD-DVD: Akin to current DVD manufacturing design, consists of a 0.6mm and 0.6mm sandwich with the data layer in the middle.

Commentary: Makes sense – no manufacturing process is perfect. Maximizing the amount of ‘good’ discs that come out of a production run relies heavily on simplifying the process as much as possible – less to go wrong and possibly spoil the disc. AS time goes on, the lessons learned by early mistakes should help to minimize this as an issue.

Copy Protection
Bluray: HD-DVD and Bluray share a common copy protection scheme known as AACS – the Advanced Access Content System. Bluray discs add an additional layer of copy protection in BD Plus, which reads and executes code off of the disc on the fly. BD Plus is an optional technology, but the added complexity for content providers and Bluray drive manufacturers alike was an issue to keep in mind.

HD-DVD: Uses AACS for copy protection.

Commentary: Will result in higher-priced Bluray players when priced against HD-DVD hardware – the requirement on the player’s CPU will be greater, leading to a need for a more powerful CPU or additional specialized hardware that handles the on-the-fly BD Plus decoding. Like not a long term issue from the price perspective, as consumer electronics such as media players quickly drop in price as competitors pile in to wage battle for marketshare.

Video Compression Scheme (Codecs)
With a 1-gigabit per second bandwidth requirement for uncompressed high definition (1080p) video, there is a clear need for a codec to fit a feature-length movie on a 25GB or 30GB disc. Both Bluray and HD-DVD support three codecs: MPEG2, the scheme used today on DVDs, and two new codecs, Microsoft’s VC-1, and H.264 MPEG4. All Bluray and HD-DVD players support each of the three codecs. The actual decision of which codec to use falls on the content provider.

Bluray: Currently a 25GB disc, supports all three codec standards. Bluray studios currently making use of MPEG2, a less efficient compression scheme by a factor of 2x or 3x than VC-1 (a comparison to H.264 MPEG4 was not made). This requires that a higher compression ratio is used, which amounts to more data containing information about how the picture should be represented is thrown away. In other words, lowered video quality due to the inefficient use of space available on the disc.

HD-DVD: Currently a 15GB or 30GB disc, supporting all three codec standards. All HD-DVD studios are making use of VC-1 on 30GB discs, with special assistance by Microsoft being provided to each with the goal of optimizing video quality.

Commentary: This is the strongest argument against Bluray. The use of MPEG2 over a newer compression scheme will in most cases result in a lower quality picture. Consumers will likely not care a whit for the issues encountered by content providers or player manufacturers, but tangibly better quality from a HD-DVD disc will hurt Bluray’s chances badly.

Hybrid Disc Technology
Hybrid discs would allow a regular DVD player to display content on one side of the disc, and a Bluray or HD-DVD player to show the same content in high definition on the other side.

Bluray: No commercial reality for hybrid discs at the current time.

HD-DVD: Hybrid DVD/HD-DVD discs are already shipping.

Commentary: Insigificant to the vast majority of consumers. Who needs a movie released today so badly that they need a hybrid disc, and can’t either rent it, or just wait 6-8 months to buy a regular HD-DVD or Bluray disc after the format war shakes out a little more? That is, unless the cost difference of a hybrid disc and regular DVD is neglible.

Transfer Rate
Like DVDs, Bluray and HD-DVD will also be useful for regular data storage – most of us know how limiting a 4.7GB disc is when the time comes to do a backup of our ever-larger hard drives.

Bluray: Faster transfer rate – ~10Mbit/sec faster than HD-DVD.

HD-DVD: While slower in sheer transfer rate, the use of a superior video codec results in a negligible difference where a movie player is concerned. The use of a red laser (opposed to the newer technology blue) and the large amount of industry experience with it allows for a higher disc spin speed to further negate the transfer rate advantage of Bluray.

Commentary: The difference in seek times, a key issue in the use of next-gen players as data drives, was not discussed. While the two formats appear equal in terms of video data transfer (a constant stream of bits), the data storage argument likely falls in favour of Bluray.

Network Connectivity
Bluray: Optional network connection interface.

HD-DVD: Mandatory network connection interface (Ethernet, no doubt). Allows for streamed content over the Internet to your player, a la Xbox 360 + Xbox Live. Also allows for occasional player updates, new language content, and – this went unmentioned during the podcast but I’ll include myself – the ability to hack and upload new instructions onto your home HD-DVD player.

Comments: With MS being in the HD-DVD camp, the features of Bluray discs go unmentioned. We can safely theorize, I imagine, that the things mentioned above are likely identical across the board.

Movie Studio Support
Bluray: Paramount, Warner Brothers, Sony, Fox, Disney.

HD-DVD: Universal, Paramount, Warner Brothers, Studio Canale. Amir points out that Warner put out 50% of the top movies of the last year – quality over quantity?

Commentary: Amir points out that movie studios could not care less about what format wins, as long as people are buying one or the other. In this he’s right – we’ve seen this illustrated brilliantly in the video game console wars between the Sony PlayStation 2 and the original Microsoft Xbox. The majority of content will go wherever people are willing to buy it.

So there you go, the major case points against Bluray/for HD-DVD as perceived by Microsoft. Bear in mind that even a blog entry of this length is still leaving out a lot of interesting info from the podcast – I highly encourage taking some time to have a listen.