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Blu-ray

It’s official. Blu-ray has won the format war over HD DVD. Now Blu-ray has a bigger job in convincing users to convert from buying DVDs to Blu-ray discs. So why would someone want to buy a Blu-ray player and pay extra for Blu-ray movies? The answer is that DVDs do not have the storage capacity to store high definition movies. The limited storage capacity of DVDs forces all DVD movies to be encoded in a standard definition format.

Most new HDTV owners will tell you, “Once you go HD, you can’t go back.” Blu-ray offers the capability to store entire HD movies on one disc, and allows HDTV owners to get the full visual effect from high definition movies.

Is it Worth it to Switch From DVD to Blu-ray?

The “Is it worth it” question depends on the user’s HDTV. First, there is no reason to have a Blu-ray player if it’s not connected to a HDTV. The main benefit of Blu-ray players is their capability to play high definition movies so a standard TV might as well use a cheaper DVD player.

The next question to ask is how big is the HDTV’s screen? Any HDTV with a screen lower than 40 inches might as well use an upscailing DVD player. The screen will be too small to see the improved 1080 lines of resolution Blu-ray offers. There could be some benefit in getting the faster 60 frames per second frame rate, but most people won’t see it.

The frame rate topic leads to the next question in whether the HDTV is 720p, 1080i or 1080p? Blu-ray movies or encoded in the 1080p format, which will greatly benefit 1080p HDTVs. TVs in the 1080i or 720p format will have to downscale the resolution or frame rate, but should still see a significant improvement over 480i DVDs.

Besides the visual benifits Blu-ray has over DVD, Blu-ray also has some noticible auido improvments. Blu-ray supports Dolby TrueHD and DTS-HD encoding which is a 7.1 uncompressed (i.e. less noise) signal. DVD can only go up to 5.1 Dolby Digital or DTS ES.

Lastly, newer Blu-ray players that are BD-Live capable offer interactive bonus features such as games and online shopping. DVD players do not offer online connectivity so someone looking for interactive features should think about switching to Blu-ray.

Differences Between Blu-ray 1.0, 1.1 and BD-Live

Blu-ray players are built accrording to the Blu-ray 1.0, 1.1 or BD-Live specification . Blu-ray movies should be able to play on all of the three different versions, but may not be able to get the full bonus feature capability. For example, BD-Live (or 2.0) Blu-ray players offer interactive online capabilities. All BD-Live Blu-ray players are required to have a built-in Ethernet port in order to allow internet connections. Blu-ray players built to the 1.0 and 1.1 specification do not require internet connections.

The main difference between Blu-ray 1.0 and 1.1 players are the increased memory and hardware requirements for 1.1 players. The increased hardware requirements are used to provide picture-in-picture content. The so called “Bonus View” capability that 1.1 offers allow users to watch interviews in a picture-to-picture window while the main movie is running.

Technical Details

Today’s DVDs have a maximum capacity of 9.4 GB (dual layer format) and are encoded using a MPEG–2 compression algorithm. This may seem like a large amount of space, but it is not enough for HD content. HD video compressed in MPEG–2 can take a data rate of approximately 8.5 GB per hour. The data rate varies greatly per video with 10 GB per hour as a maximum estimate. Therefore, you would only be able to store about one hour of HD video on today’s DVDs. Obviously, this poses a problem for the average two hour movie.

New technology was necessary in order to store more data, which could be done by increasing the storage space on the disc or by improving the compression algorithm. Using a lower wavelength blue laser instead of a red laser allowes more storage space per disc. Using a more efficient MPEG–4 compression algorithm reduces the data rate to approximately 4.5 GB per hour of video (with 5.4 GB per hour as a maximum estimate). Hence, a new format had to be developed to incorporate the blue laser and an improved compression algorithm. This is where Blu–ray and HD DVD come into the picture.

Blu-ray vs HD DVD

With billions of dollars in licensing revenue at stake, two different high definition formats emerged. In one corner, there was the HD DVD group lead by Toshiba, NEC, Universal, Microsoft, Intel, and the DVD Forum. In the other corner was the Blu–ray group led by Sony, Philips, Fox, Disney, Apple, MGM, Electronic Arts, Dell, Hewlett Packard, Hitachi, Samsung, and others. In the end, it was Sony giving an undesclosed large sum of money to Warner Brothers that won the battle for blu-ray.

HD DVD disks can store 15GB for a single layer, 30GB for dual layers, or 45GB for three layers. It offers both MPEG–2 and the more efficient MPEG–4 compression algorithms. The biggest advantage that HD DVD had over Blu–ray was its backwards compatibility with DVD.

Blu–ray can store 25GB for single layer or 50GB for dual layer disks. Like HD DVD, Blu–ray offers MPEG–2 and the more efficient MPEG–4 compression algorithms. The biggest advantage that Blu–ray has over HD DVD is that the disk space is almost future proof. Sony has announced 8–layer 200 GB Blu–ray disks are in the works. The comparison chart below shows the whopping amount of hours of video a 200GB disk can store.

Comparison Chart


Format
SD MPEG–2 (3.6 GB/hr)
HD MPEG–2 (8.5 GB/hr)
HD-MPEG–4 (4.5 GB/hr)
DVD – 9.4GB dual layer 2.6 hours 1.1 hours 2.1 hours
HD–DVD – 30 GB dual layer 8.3 hours 3.5 hours 6.7 hours
Blu–ray – 50 GB dual layer 13.9 hours 5.9 hours 11.1 hours
HD–DVD – 45 GB 3–layer 12.5 hours 5.3 hours 10 hours
Blu–ray – 200 GB 8–layer 55.5 hours 23.5 hours 44.4 hours


HD DVD / Blu–ray Tips

  1. For information on computer Blu-ray and HD DVD ROM drives, go to the HTPC video playback page.
  2. Both Blu–ray and HD DVD players are backwards compatible with DVDs. Both formats have announced hybrid disks with regular DVD encoding on one side, and HD encoding on the other side.
  3. Standard DVDs can be upscaled to high definition resolution. The video quality won’t be at the same level as Blu–ray or HD DVD, but it will beat standard definition video. See this upscaling section for more information.
  4. HDMI 1.3 specification brings added benefits to Blu–ray players including the transmission of Dolby TrueHD and DTS–HD, which could bring lossless audio signals to your receiver. The HDMI 1.3 specification can also increase the color bit depth, which could bring trillions of color combinations to your HDTV set.


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