Blu Ray vs. DVD: What is the Difference?

The arrival of HDTV in the late 1990s caused great excitement for the discerning viewers, who like to watch movies with better image details and in clearer resolution. HDTV enabled the viewer to get an unequalled picture quality; great surround sound with 5.1 channels of digital audio output and a matchless wide screen viewing experience. The viewers lapped up the HDTV technology, but there was a slight shortcoming: HDTV was only available in “broadcasting format”, and there was no facility of “playback”. In simpler words, you could enjoy HDTV only through your broadcaster. If you wanted to record a program, or play back a movie, then it was back to the older formats, i.e., VCD or DVD. Therefore, there was a demand for a similar, HDTV quality pictures and sound which could be used to record and playback just like the conventional DVDs.

The consumer electronics industry was quick to understand this demand, and some of the heavyweights like Sony, Philips, Samsung, Apple, Dell and LG joined forces to develop a technology for this purpose. The conventional DVD works this way: the data is stored on a disc, and the reader “reads” this data by using a red laser. The scientists hit upon a simple solution: use a violet-blue laser instead of the red laser! Why? Because the violet-blue (or blue) laser has a much shorter wavelength (405 nm) than that of the red laser (650 nm). ( An nm is a billionth part of a metre). Therefore, the blue laser can be focused with a much greater precision on a particular spot on a disc. This means that more data can be packed on the same disc, and the blue laser will read it correctly. Thus, the blue ray disc was born! Later, as the name “blue ray” was considered to be too generic, the technology was rechristened as “Blu Ray”. The consortium of manufacturers that developed this technology came to be known as the Blu Ray Disc Association, or simply BDA. The blu ray disc is also called BD in short.

A blu ray disc, or a BD is different from DVD in many respects. The main points of difference are:

1) The disc reader for a DVD uses the red laser, while the reader for a BD uses a violet-blue laser.

2) The storage capacity of a standard DVD is 4 GB, whereas the storage capacity for a standard BD is 25 GB. A double-layered BD has, well, twice the storage capacity, that is, 50 GB.

3) More storage capacity means more playback time. On a BD, you can store about 24 hours of standard-definition (SD) or about 9 hours of high definition (HD) video.

4) A BD can playback a resolution of 1920x1080p, while a conventional DVD can play back at a resolution of 640x480p. This means that the picture quality and resolution is way better in case of blu ray disc.

5) The blu ray disc offers a much higher level of interactivity. The menu structure is more advanced in case of a BD, and is available even during the playback.

6) Blu ray discs are more durable, since they are hard coated using a special technology. This means more protection from dirt, dust and the absolutely irritating scratches!

7) Last, but definitely not the least, is that the current blu ray players are backward compatible. This means that once you purchase a new blu ray player, you can always play back your collection of DVD on the same player. (No, you cannot play a blu ray disc on you current DVD player). So, if your DVD player has become redundant, there is still hope for your prized DVD collection. That is, indeed, some consolation!

In addition, the blu ray discs also offer some other benefits. It is available in various formats like read only (BD-ROM), recordable (BD-R) and rewritable format (BD-RW). A blu ray user can create play lists, re-arrange and edit the programs recorded on the BD, and search for empty spaces on the disc, so as to avoid recording over an existing program. Also, BDs offer a bit rate which is five times that of DVDs and up to 32 streams of audio. Translated from Geek Speak to plain English, this means that you can enjoy a much, much higher quality (and quantity) of video and audio playback on a blu ray disc as compared to a DVD!

Well, this hub is not about HD-DVD, it is about blu ray! Nevertheless, no discussion about blu ray can be complete without mentioning HD-DVD.  So, what exactly is HD-DVD? While the blu ray technology was being developed by the Blu Ray Disc Association (BDA), a parallel platform was being developed independently. This was called HD-DVD, developed by Toshiba and NEC and based on the same violet-blue laser. In the beginning, this led to a sort of “format war” between the blu ray and the HD-DVD. Later, the blu ray surged ahead, largely because it had the support of the overwhelming majority of the industry. Eventually, in February 2008, Toshiba officially announced that it will stop the production and further marketing of HD-DVD players. In fact, the Toshiba HD-DVD player is the only HD-DVD player manufactured ever!

Well, the future is already here! Almost all the new movie releases are also being done in the blu ray format. It is expected that with the rapid popularization of the blu ray and the industry support, demand will increase. This will lead to more production, and as a result, lower costs for the consumer. Blu ray is set to rule the roost for at least a few years to come. The manufacturers of the blu ray players are also sweetening the deal for the new customers by making these players backward compatible, i.e., you can play your collection of DVDs on the blu ray player. There is already a range of blu ray players available from a host of manufacturers. Bring one that suits your purpose and pocket, sit back and enjoy your movies!