CD vs. DVD vs. Blu-ray

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CD

The idea of the Compact Disc was first brought to light in 1969 by Antonio Rubbiani who had shown that a video disc was possible several years earlier. It was first developed by Philips who began to take the project serious in 1977 and there were several names discussed but Compact disc was settled on. The disc was originally 11.5cm in diameter but to accompany Beethoven’s 9th Symphony so they increased the size to 12cm to contain all of the 74 minute track. For several years Sony and Philips worked together on developing the idea of the Compact Disc however in 1980, both parties agreed on the criterions for the disc and both started developing their own ideas. In 2000 the CD reached its highest total of sales with 2.455 billion sales worldwide . Since then however due to electronic downloading, the sales of CDs has decreased dramatically. [1]

DVD

DVD stands for Digital Versatile Disc. Sony and Phillips brought forward this new idea in 1994. The DVD was to be the successor and eventually the usurper to the VHS tape, which was in vast use at the time. The biggest difference was that the DVD had almost ten times the data capacity of the CD-ROM and the VHS. The visual quality of images displayed on the new DVD disc would be far to superior to that of the VHS and the sound quality would also be an improvement to that of the already crisp sound of the CD-ROM. Before DVD, computer games would have to be stored on numerous discs due to lack of storage capability on the discs. The DVD principle changed this as a result of a layering technique, the DVD discs were able to store as much as 7.4 gigabytes on them, allowing games to be stored on the one disc. This layering technique also changed the visual experience. On the old laser discs one would generally have to flip the disc over to continue with the film but again because of the storage capability, movies could be stored on one side of the disc. DVD after its release in 1994 took the digital world by storm. By 2003 it began to usurp VHS in many countries and in the present day VHS is virtually non-existent. Its ability to store large amounts of data into one disc is what allowed it to become so popular with the general population and still is today (Chapin 1999). [2]

Blu-Ray

Blu-Ray is new optical disc format that is rapidly replacing DVD. The format offers more than five times the storage capacity of traditional DVDs and can hold up to 25GB on a single-layer disc and 50GB on a dual-layer disc. The benefit of using a blue-violet laser (405nm) is that it has a shorter wavelength than a red laser (650nm), which makes it possible to focus the laser spot with even greater precision. Because of this data to be packed more tightly and stored in less space, therefore possible to fit more data on the disc even though it's the same size as a CD/DVD. This together with the change of numerical aperture to 0.85 is what enables Blu-ray Discs to hold 25GB/50GB. Recent development by Pioneer has pushed the storage capacity to 500GB on a single disc by using 20 layers. Blu-Ray discs can hold over 9 hours of high-definition (HD) video on a 50GB disc.
About 23 hours of standard-definition (SD) video on a 50GB disc. The Blu-Ray disc is expected to replace DVD’s. Many Major Movie Studios have released titles on Blu-Ray. The two formats however are expected to co-exist for quite some time until HDTV’s become more widespread. [3]

Comparisons

Storage Capacity

  • CD = 700MB (80Mins)
  • DVD = 4.7GB
  • Blu-Ray = 25GB

Size

  • All 120mm in diameter.
  • All 1.2mm in thickness.

Media Type

  • CD = Optical Disc
  • DVD = Optical Disc
  • Blu-Ray = High Density Optical Disc

[4] [5] [6]

References

1. BBC (8th November 2012) http://news.bbc.co.uk/2/hi/technology/6950933.stm

2. Chapin.R (1999)”History of DVD” Web-based Blog, 24 September: http://www.miqrogroove.com/writing/history-of-dvd/ [accessed 8th November 2012]

3. Blu-Ray (8th November 2012) http://www.blu-ray.com/faq/#bluray_developers

4. Wikipedia (8th November 2012) http://en.wikipedia.org/wiki/CD

5. Wikipedia (8th November 2012) http://en.wikipedia.org/wiki/Dvd

6. Wikipedia (8th November 2012) http://en.wikipedia.org/wiki/Blu-ray_Disc

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