This is a technical comparison between the two HD formats competing for your hard earned dollars in the next generation format war. However since this is a blog, I'll add my two cents regarding each feature.
Looking at the
high definition wiki comparison, you can see that quite a few of the specifications are similar. Both use a 405 nm blue-violet laser, have the same 1080p resolution, support the exact same video codecs and can support the same audio codecs (albeit with some caveats which I'll explain in a bit).
Video CodecsBoth formats support
MPEG-2, the same codec used on standard definition DVD's (although it uses a specific profile that better supports the higher bit rate and larger resolution of high definition media). They also both support the next generation
H.264/MPEG-4 AVC and
VC-1 codecs that are more efficient (uses less space at equal or greater quality). Since Blu-ray has the larger storage capacity you'll see more if it's titles use MPEG-2 then HD DVD titles, while the HD DVD camp almost always uses the newer codecs since storage space on those discs are at a premium.
My Take - Since a properly done film transfer will look great in either of the three codecs, neither HD DVD nor Blu-ray has the advantage here.
Audio CodecsA quick primer on supported audio codecs is in order. I like to group them into three categories: last generation lossy, next generation lossy and next generation lossless formats.
The last generation lossy formats are the same Dolby Digtal/DTS codecs you've been listening to on DVD's although with a higher bitrate when used on the new HD formats. Because of the higher bitrate they should sound better than the equivalent soundtrack on a standard DVD. These are the old standby codecs for home theater systems (like mine) that don't have the equipment to support the newer generation codecs.
The next generation lossy codecs include Dolby Digital Plus and DTS-HD High Resolution. Although they still "throw away bits" in order to save space they still sound absolutely amazing, much more so that then the last generation codecs. The HD DVD versions of
King Kong and
Transformers use Dolby Digital Plus as their high-end audio codec and both titles have been praised for their extremely high quality audio.
The lossless category of audio codecs consists of Dolby TrueHD and DTS-HD Master Audio. These advanced lossless codecs are bit-for-bit identical to the studio masters but take up about half the space as Linear PCM (which is pure uncompressed digital audio). Linear PCM is still available on both formats although because of its large file size you'll almost never see it on a HD DVD title. Dolby TrueHD, DTS-HD Master Audio and Linear PCM are considered the premium high-end codecs by most audiophiles.
Like I mentioned earlier, both HD DVD and Blu-ray can support any of these codecs, but only HD DVD makes Dolby Digital Plus and Dolby TrueHD support mandatory. This means that every HD DVD player ever made will decode both of these two codecs inside the player. With Blu-ray both of these codecs are optional which means that the manufacture can elect to include internal player decoding if it wants but it isn't required (in fact most low end Blu-ray players do not natively decode any of these high end codecs). Internal decoding of audio codecs is important if you want to hear all the auxiliary sounds such as the swish when you navigate menus and such. If you don't care about these auxiliary sounds you can elect to decode these codecs in your A/V receiver, provided that you have a new HDMI 1.3 model. Both HD DVD and Blu-ray support DTS-HD High Resolution and DTS-HD Master Audio as optional codecs.
My take - HD DVD wins for better audio codec support simply because it makes two high end codecs mandatory on all its players. This means even a low cost HD DVD player will have Dolby TrueHD support while typically only a higher end Blu-ray player will have this feature.
Storage CapacityThe most talked about difference between the two formats has to be the total storage capacity. The Blu-ray Disc standard specifies 25 GB per layer, so on a maximum 2 layer disc you will have 50 GB of available storage. The HD DVD specification is a lower 15 GB per layer which results in a maximum 30 GB per disc. The HD DVD camp announced an upcoming 17 GB per layer, max 3 layer disc that theoretically be capable of 51 GB of total disc space. Since it's painfully obvious they did this to counter Blu-ray's 50 GB disc's capacity (why not stick with the current 15 GB layer standard?) and that it's unknown if this will work with current players I won't include this as advantage for the HD DVD camp just yet (and even if it turns out to be true, 1 GB difference isn't much of an advantage).
More storage per disc means more video that can be stored, as well as room for either lossless or uncompressed PCM audio and other extras like deleted scenes, multiple language tracks, ect... Does HD DVD, having 20 GB of effective less capacity that that of Blu-ray mean anything in the real world? Looking at both various
HD DVD and
Blu-ray movie sizes it appears that the 30 GB limitation of HD DVD is a factor when authoring a HD movie. Using my previous example, both King Kong and Transformers on HD DVD didn't include a higher end Dolby TrueHD or DTS-HD Master Audio soundtrack in order to fit the video plus with all the extras. Although the audio is still spectacular with Dolby Digital Plus, I'm sure the studio would have included one of the lossless codecs if either title was released on Blu-ray.
My take - I have to give the nod to Blu-ray since it could be argued that HD DVD 30 GB maximum capacity limits studios from including the lossless audio codecs so desired by the high end audiophiles, even if it's not discernible by the average ear.
Region CodingThere is no Region Coding in the HD DVD specification which means titles from any country can be played in any player. Blu-ray has elected to use a three region system, similar to the old DVD method of limiting what discs play in what country's player.
My take - Although only about 1/3 of Blu-ray discs use region coding, its still archaic and anti-consumer. HD DVD's region free policy wins this round.
Player ProfilesThis is something that doesn't exist on HD DVD players. Every HD DVD player supports every feature of the HD DVD standard from day one. For a strange reason, the Blu-ray association decided to have three different profiles on their players, depending on when they were introduced in the marketplace.
Profile 1.0 (Grace Period Profile) were any Blu-ray player manufactured before November 1st, 2007. They have no local storage capability, no internet connection capability and features like a secondary video and audio decoders are optional (to date no profile 1.0 player has any of these optional features).
Profile 1.1 (Final Standard Profile) is any Blu-ray model introduced after November 1st, 2007. It's now called Bonus View rather than Final Standard profile as to not confuse the consumer who might think a 1.0 Profile player won't play new Blu-ray discs. The 1.1 Profile mandates that every player includes 256 MB of local storage and includes a secondard video/audio decoder (needed for picture in picture). It does not require internet connection capability.
Profile 2.0 (BD-Live) has all the features of Profile 1.1 but ups the local storage capability to 1 GB and makes the internet connection capability mandatory. There is no defined date for when Profile 2.0 players come to market but apparently
Daewoo has already announced a Blu-ray player that is 2.0 compliant. The Sony PlayStation 3 is also rumored to become 2.0 compliant with a firmware update.
My Take - HD DVD's decision to have one standard for all players was the smart move here. This meant that studio's always knew the capabilities of all the players on the market, therefore could include all the special features like picture in picture and web interactivity from day one. Early Blu-ray adopters (PS3 owners being the exception since the console was upgradeable to 1.1) might be upset to find out that their Profile 1.0 players won't be able to play these extra features (although the main movie should play just fine) with the newer titles.
Bitrate The higher the bitrate, the better the quality of the video and audio, all other things being equal. Blu-ray supports a maximum bitrate for Audio+Video+Subtitles at 48.0 Mbit/sec while HD DVD maxes out at 30.24 Mbit/sec. Not every title uses a bitrate higher than 30 Mbit/sec, but some do and that's where Blu-ray has an advantage.
My Take - Here's where Blu-ray has the upper hand over HD DVD. Whether the average person can see the difference might be debatable but a higher bitrate usually means video that is compressed less and therefore should look better.
Hardcoating of disc As a father of 2 young girls who have scratched at least 50% of my DVD collection, here's a feature thats near and dear to my heart. Because Blu-ray uses a technology that hold the data much closer to the surface of the disc than HD DVD, it needs a hard coating to protect the disc from scratches. They teamed up with TDK to come out with a new surface coating called
Durabis that is incredible when it comes to resisting scratches and markers. Take a look at the
evidence to see how well this works. This hard coating is optional on HD DVD discs, although I haven't seen any in the market.
My Take - Blu-ray wins here. I wish they had this during the DVD years and am surprised HD DVD didn't make this a mandatory feature. Perhaps they want us to buy multiple copies of the same titles like we did with DVD's.
Other Differences I haven't discussed the DRM and interactivity format differences between Blu-ray and HD DVD simply because I don't have enough technical knowledge to make an educational comment.
ConclusionAs you can see, there really isn't one perfect format. If I had to build one based on the strengths of both, I would select the capacity, higher bitrate and durability of Blu-ray, along with the single profile, mandatory audio codec and lack of region coding of HD DVD. Unfortunately because of corporate ego and greed we'll never see such a format and we'll have to wait out this war a bit longer.
