Are you still using traditional CDs and DVDs? So you are not viewing or using high definition audio or video content. If so, why don’t try some high definition videos and if you are interested, first of all things you should get Blu – ray discs and players. You can ask me why we should try Blu – ray discs, while already getting a good and decent quality content with traditional DVDs. The basic reason will be you should have knowledge about what is the basic difference in operation and features between DVD and Blu – Ray Discs (BD), if you completely know these things you definitely start your new digital experience with Blu – Ray discs i.e. high definition content.
Definition of Blu – Ray disc technology:
Traditional DVDs are optical discs which are developed as a technology in 1997 and revolutionized digital media for more than 10 years. The capacity of DVD is five times more than that of CD and DVDs are very advanced technology in the year 2000. But technology never stopped running to the future. As a justification to this fact, 10 years later, and scientists developed another technology in 2006 Blu – ray disc was discovered and it became a digital product that provides high definition quality audio and video content to viewers and also acts as very high or large capacity medium. Now we can find what are the computational and features difference between DVDs and BDs.
The BD format of discs were developed to enable recording, rewriting and playback of high-definition video (HD), as well as storing large amounts of data. 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. This extra capacity combined with the use of advanced video and audio codecs will offer consumers an unprecedented HD experience.
While current optical disc technologies such as DVD, DVD±R, DVD±RW, and DVD-RAM rely on a red laser to read and write data, the new format disc uses a blue-violet laser instead, hence the name Blu-ray. Despite the different type of lasers used, Blu-ray products can easily be made backwards compatible with CDs and DVDs through the use of a BD/DVD/CD compatible optical pickup unit.
Operational difference between DVDs and Blu – ray discs BDs
The advantage of using a blue-violet laser (405nm) for reading 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. This allows data content to be packed more tightly and stored in lesser space compared to other disc writing laser, so it’s possible to fit more data on the disc even though it’s the same size as a 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 scientists has pushed the storage capacity to 500GB on a single disc by using 20 layers.
A single-layer Blu-ray disc, which is roughly the same size as a DVD, can hold up to 27 GB of data – that is more than two hours of high-definition video or about 13 hours of standard video. A double-layer Blu-ray disc can store up to 50 GB, enough to hold about 4.5 hours of high-definition video or more than 20 hours of standard video. And there are even plans in the works to develop a disc with twice that amount of storage.
Features & Functions CD
Storage capacity: 700MB
Laser: red
Numerical aperture (NA): 0.60
Disc diameter & thickness: 120mm & 1.2mm
Video bit rate (max): 1.12Mbps
Video Codec: MPEG-1
Audio Codec: MPEG-1 Audio Player II
Quality: Medium
Formats: CD – R
CD – RW
CD – ROM
Features & Functions DVD
Storage capacity: 4.7 GB (single layer)
8.5GB (dual layer)
Laser: red laser (650 nm)
Numerical aperture (NA): 0.60
Disc diameter & thickness: 120mm & 1.2mm
Track Pitch: 0.74 µm
Data transfer rate (data): 11.08Mbps(1x)
Data transfer rate(video/audio):10.08Mbps(<1x)
Video bit rate (max): 9.8Mbps
Video Codec: MPEG-2
Audio Codec: Linear PCM
Dolby Digital
DTS Digital Surround
Quality: Standard
Formats: DVD – R
DVD – RW
DVD – ROM
Features & Functions Blu-ray Discs (BD)
Storage capacity: 25GB (single layer)
50GB (dual layer)
Laser: blue-violet (405 nm)
Numerical aperture (NA): 0.85
Disc diameter & thickness: 120mm & 1.2mm
Track Pitch: 0.32 µm
Data transfer rate(data): 36.0Mbps (1x)
Data transfer rate(video/audio):54.0Mbps(1.5x)
Video bit rate (max): 40.0Mbps
Video Codec: MPEG-2
MPEG-4 AVC
SMPTE VC-1
Audio Codec : Linear PCM
Dolby Digital
DTS Digital Surround
Dolby Digital Plus
Dolby True HD
DTS-HD
Quality: High Definition (HD)
Formats: BD – R
BD – RW
BD – ROM
BD – RE (High Definition)
These are the basic differences in features and functions between traditional DVDs and BDs. If we move and get in depth knowledge there are lots of additional features provided by BDs to this modern digital world in formats and support. For example the High definition content were already introduced for music and movies with almost every studio of Hollywood is producing High Definition (HD) videos and audios and their releases are becoming more and more gettable for only those people who are using High Definition Television (HDTV) and other players that supports High Definition (HD)Content formats. As TV sets and movie studios make the move to high definition, consumers are going to need playback systems with a lot more storage capacity. For more clear picture and sound quality you always need a medium which should be of larger capacity storage medium. The additional benefits in using Blu-Ray Discs are given.
You can record high-definition television (HDTV) without any quality loss at any time.
Instantly skip to any spot on the disc without much effort.
Record one program while watching another on the same disc
You can even create play lists for your own choice.
Edit or reorder programs recorded on the disc.
Automatically search for an empty space on the disc to avoid recording over a program or data on the disc
Access the Web to download subtitles and other extra features which are available online.
It doesn’t mean that every time you need to connect internet for playback or doing some other operations in the Blu – Ray discs. You can simply get additional features or technical support through online helpline.
More technical operational difference
Discs store digitally encoded video and audio information in pits – spiral grooves that run from the center of the disc to its edges. A laser reads the other side of these pits — the bumps – to play the movie or program that is stored on the DVD. The more data that is contained on a disc, the smaller and more closely packed the pits must be. The smaller the pits (and therefore the bumps), the more precise the reading laser will be.
Unlike current DVDs, which use a red laser to read and write data, Blu-ray uses a blue laser (which is where the format gets its name). A blue laser has a shorter wavelength (405 nanometers) than a red laser (650 nanometers). The smaller beam focuses more precisely, enabling it to read information recorded in pits that are only 0.15 microns (µm) long – this is more than twice as small as the pits on a DVD. Plus, Blu-ray has reduced the track pitch from 0.74 microns to 0.32 microns. The smaller pits, smaller beam and shorter track pitch together enable a single-layer Blu-ray disc to hold more than 25 GB of information – about five times the amount of a DVD capacity.
Each Blu-ray disc is about the same thickness (1.2 millimeters) as a DVD. But the two types of discs store data differently. In a DVD, the data is sandwiched between two polycarbonate layers, each 0.6-mm thick. Having a polycarbonate layer on top of the data can cause a problem called birefringence, in which the substrate layer refracts the laser light into two separate beams. If the beam is split too widely, the disc cannot be read. Also, if the DVD surface is not exactly flat, and is therefore not exactly perpendicular to the beam, it can lead to a problem known as disc tilt, in which the laser beam is distorted. All of these issues lead to a very involved manufacturing process.
Blu – Ray Discs & products:
Already top studios from Hollywood have been announced their releases of movies in Blu-ray discs and Blu – ray disc movies are supported by thousands of studios all over the world. Moreover these High Definition (HD) movies or Blu –ray content movies are very attractive and lots of people are buying it. However the price of Blu – ray movies which are high quality and Blu- ray disc players are a little bit costlier when compared to ordinary traditional DVD players. The movies are very high quality and sound, picture quality are perfect to view with, so all are accepting the expense. Also the Blu-ray disc players should have a blue-violet reading laser, so these players can also read DVDs and CDs that are in normal use today, but, ordinary DVD players which are in use now cannot play or read BD content or movies. The trend will change, since there are only few manufacturers in the world producing Blu-ray discs and players and that is what the reason for costlier rate of Blu-ray discs and players. Soon it will become cheaper than now. So enjoy High Definition movies and audio with Blu-ray discs.