16-10-2012, 11:24 AM
Blu-Ray DISC
Blu-Ray Disc Presentation.doc (Size: 176 KB / Downloads: 29)
ABSTRACT:
The thrust for an advanced format of data storage on optical disc led to revolutionary introduction of BLU-RAY DISC. This advances in the race against its competitors DVD (Digital Video Disc) & AOD (Advanced Optical Disc) in that it has high storage capacity, advanced security and privacy features and the A/V high quality O/P (generally video) of the media files stored on it make’s it quite unique & gives an edge over the others, letting BD to be widely adaptable in every application possible.
Surprisingly, the necessity for a next generation disc had begun in 1994 even before the advent of the DVD in the market in 1996. The then scientists predicted the limitations of the DVD format & begun working on BD even before DVD's release.
This paper essentially is confined with the structure, construction, reading issues & advantages of the Blu-Ray Disc. To be effective, at every stage the disc is compared with DVD.
INTRODUCTION:
The founding stones for the Blu Ray Disc technology were laid in 2002 by the Blu Ray Disc Association (BDA) in an attempt to overcome the drawbacks in DVD's. This attempt has almost reached the zenith & the world now is shortly about to use a disc of an incredible storage capacity & with almost all the apex features incorporated, that ensures user security and privacy and enables one to operate the disc in the most efficient and convenient way ever imagined.
WHY BD?
Early in 1997, a new technology emerged that brought digital sound and video into homes all over the world almost thrashing out the then conventional CD's. It was called DVD, and it revolutionized the movie industry. This format ruled the market for over a span of 5 years, but now is facing some very tight challenges. Here are some reasons why there’s been a rush to change from the current format of DVD:
SIZE :
A single-sided, standard DVD can hold 4.7 GB (gigabytes) of information. That's about the size of an average two-hour, standard-definition movie with a few extra features. But a high-definition movie, which has a much clearer image, takes up about five times more bandwidth and therefore requires a disc with about five times more storage. 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, which a DVD cannot support. Also, more space on a single disc invariably results in higher disc size. This bulky size of the disc is neither convincing nor convenient.
SECURITY :
CSS is toast, thanks to some smart programmers in Europe and some foolish programmers at the now-defunct Xing Technologies. The group that created the DeCSS software figured out how to break the encryption by reverse engineering Xing's DVD decryption key, which wasn't properly protected. The end result is that DVDs can be copied as easily as music CDs. The market hates the fact that the DVD format is now vulnerable and there's nothing they can do about it, and are eager for a new format that is much more secure.
QUALITY :
The final reason for the change is video quality. DVD video is presented in 480p, or 480 lines per screen, progressive scanned video. High Definition TV (HDTV) is presented in 720p or 1080i. You won't notice any difference without a high definition television, but if you do have an HDTV set, the improvement in quality is very noticeable. The quality of the video o/p of the media files on a DVD or a CD is not up to the mark.
SOLUTION :
The industry is set for yet another revolution with the introduction of Blu-ray Discs (BD). With their high storage capacity, Blu-ray discs can hold and playback large quantities of high-definition video and audio, as well as photos, data and other digital content. Also incorporated are some advanced security and privacy options and convenient accessibility features.
A single sided blu ray disc has the capacity to store information of about 27 gigabytes, that’s about the size of 13 hr standard definition movie or more than 2.5 hrs of a high definition movie. While the double layered one can store to about 54 gigabytes. This enormous storage capability is considered to be the major plus point of the blu ray disc to that of the conventional DVD’s in the market right now.
STRUCTURE:
The structure of the Blu-Ray disc is shown as below. It differs from the traditional DVD that, in a DVD the data is sandwiched between two 0.6mm polycarbonate layers. While in the case of a BD the data layer is placed on a 1.1mm polycarbonate layer. To prevent the data on the top of the disc from getting erased, the data layer is covered by a 0.1 mm protection layer. This makes the size of all the CD's DVD's & the BD's constant. This packing of the data has many advantages which will be discussed in the later sections.
STORAGE:
It should be noticed that whatever form of the disc may be under consideration the data on the disc is stored on a SPIRAL TRACK running from the centre of the disc to the end of the diameter of the disc. This spiral starting from the centre of the disc gives the flexibility for the disc to be smaller in size than that of the conventional 120 mm. On this spiral tracks exists the BUMPS which actually hold the data. These bumps lie all along the spiral track. These bumps are often called pits. Viewed from the top of the disc these bumps look like PITS.
DATA RETRIEVAL (CONTINUOUS):
When recording, deleting or editing operations are performed repeatedly, small areas of empty space will occur across the disc. These small areas can be used to record a new Real-Time file, which results in a single Real-Time file composed of many small extents scattered across the disc. A group of these extents, each of which is recorded on contiguous logical sectors, is called an Expanse. The Expanse is conceptually a contiguous area to be read, and may include small areas in which Real-Time data is not recorded.
When a single Real-Time file is made up of several expanses, the file is read by jumping from one expanse to the next and reading the expanses in order. However, when jumping from one expanse to another, the disc rotation speed needs to be changed and the optical pickup needs to be moved to a different radius on the disc. Although data cannot be retrieved from the disc during this interval, the decoding/playback of video/audio data must continue without interruption.
To prevent interruption in video/audio playback while reading data from the disc, the buffer memory must not be emptied of data before readout from the next expanse becomes possible. This requirement for continuous supply of data is necessary to insure seamless playback. Therefore the minimum expanse size is defined such that the buffer memory does not become empty when jumping from one expanse to another on the disc.
CONCLUSION :
It would definitely take a considerable time for the Blu-Ray disc to hit the market & completely takeovers the DVD share hold. Because of the low level compatibility (BD readers able to read both the DVD’s and the CD’s), the task might become a little simpler. But, the high cost of the reader might hinder its quick development. Anyways soon or later this mass storage optical device is going to replace the DVD & let the user experience a world high quality & disc space (Quality & Quantity ensured) with high level of security and privacy ensured.
Blu-Ray Disc Presentation.doc (Size: 176 KB / Downloads: 29)
ABSTRACT:
The thrust for an advanced format of data storage on optical disc led to revolutionary introduction of BLU-RAY DISC. This advances in the race against its competitors DVD (Digital Video Disc) & AOD (Advanced Optical Disc) in that it has high storage capacity, advanced security and privacy features and the A/V high quality O/P (generally video) of the media files stored on it make’s it quite unique & gives an edge over the others, letting BD to be widely adaptable in every application possible.
Surprisingly, the necessity for a next generation disc had begun in 1994 even before the advent of the DVD in the market in 1996. The then scientists predicted the limitations of the DVD format & begun working on BD even before DVD's release.
This paper essentially is confined with the structure, construction, reading issues & advantages of the Blu-Ray Disc. To be effective, at every stage the disc is compared with DVD.
INTRODUCTION:
The founding stones for the Blu Ray Disc technology were laid in 2002 by the Blu Ray Disc Association (BDA) in an attempt to overcome the drawbacks in DVD's. This attempt has almost reached the zenith & the world now is shortly about to use a disc of an incredible storage capacity & with almost all the apex features incorporated, that ensures user security and privacy and enables one to operate the disc in the most efficient and convenient way ever imagined.
WHY BD?
Early in 1997, a new technology emerged that brought digital sound and video into homes all over the world almost thrashing out the then conventional CD's. It was called DVD, and it revolutionized the movie industry. This format ruled the market for over a span of 5 years, but now is facing some very tight challenges. Here are some reasons why there’s been a rush to change from the current format of DVD:
SIZE :
A single-sided, standard DVD can hold 4.7 GB (gigabytes) of information. That's about the size of an average two-hour, standard-definition movie with a few extra features. But a high-definition movie, which has a much clearer image, takes up about five times more bandwidth and therefore requires a disc with about five times more storage. 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, which a DVD cannot support. Also, more space on a single disc invariably results in higher disc size. This bulky size of the disc is neither convincing nor convenient.
SECURITY :
CSS is toast, thanks to some smart programmers in Europe and some foolish programmers at the now-defunct Xing Technologies. The group that created the DeCSS software figured out how to break the encryption by reverse engineering Xing's DVD decryption key, which wasn't properly protected. The end result is that DVDs can be copied as easily as music CDs. The market hates the fact that the DVD format is now vulnerable and there's nothing they can do about it, and are eager for a new format that is much more secure.
QUALITY :
The final reason for the change is video quality. DVD video is presented in 480p, or 480 lines per screen, progressive scanned video. High Definition TV (HDTV) is presented in 720p or 1080i. You won't notice any difference without a high definition television, but if you do have an HDTV set, the improvement in quality is very noticeable. The quality of the video o/p of the media files on a DVD or a CD is not up to the mark.
SOLUTION :
The industry is set for yet another revolution with the introduction of Blu-ray Discs (BD). With their high storage capacity, Blu-ray discs can hold and playback large quantities of high-definition video and audio, as well as photos, data and other digital content. Also incorporated are some advanced security and privacy options and convenient accessibility features.
A single sided blu ray disc has the capacity to store information of about 27 gigabytes, that’s about the size of 13 hr standard definition movie or more than 2.5 hrs of a high definition movie. While the double layered one can store to about 54 gigabytes. This enormous storage capability is considered to be the major plus point of the blu ray disc to that of the conventional DVD’s in the market right now.
STRUCTURE:
The structure of the Blu-Ray disc is shown as below. It differs from the traditional DVD that, in a DVD the data is sandwiched between two 0.6mm polycarbonate layers. While in the case of a BD the data layer is placed on a 1.1mm polycarbonate layer. To prevent the data on the top of the disc from getting erased, the data layer is covered by a 0.1 mm protection layer. This makes the size of all the CD's DVD's & the BD's constant. This packing of the data has many advantages which will be discussed in the later sections.
STORAGE:
It should be noticed that whatever form of the disc may be under consideration the data on the disc is stored on a SPIRAL TRACK running from the centre of the disc to the end of the diameter of the disc. This spiral starting from the centre of the disc gives the flexibility for the disc to be smaller in size than that of the conventional 120 mm. On this spiral tracks exists the BUMPS which actually hold the data. These bumps lie all along the spiral track. These bumps are often called pits. Viewed from the top of the disc these bumps look like PITS.
DATA RETRIEVAL (CONTINUOUS):
When recording, deleting or editing operations are performed repeatedly, small areas of empty space will occur across the disc. These small areas can be used to record a new Real-Time file, which results in a single Real-Time file composed of many small extents scattered across the disc. A group of these extents, each of which is recorded on contiguous logical sectors, is called an Expanse. The Expanse is conceptually a contiguous area to be read, and may include small areas in which Real-Time data is not recorded.
When a single Real-Time file is made up of several expanses, the file is read by jumping from one expanse to the next and reading the expanses in order. However, when jumping from one expanse to another, the disc rotation speed needs to be changed and the optical pickup needs to be moved to a different radius on the disc. Although data cannot be retrieved from the disc during this interval, the decoding/playback of video/audio data must continue without interruption.
To prevent interruption in video/audio playback while reading data from the disc, the buffer memory must not be emptied of data before readout from the next expanse becomes possible. This requirement for continuous supply of data is necessary to insure seamless playback. Therefore the minimum expanse size is defined such that the buffer memory does not become empty when jumping from one expanse to another on the disc.
CONCLUSION :
It would definitely take a considerable time for the Blu-Ray disc to hit the market & completely takeovers the DVD share hold. Because of the low level compatibility (BD readers able to read both the DVD’s and the CD’s), the task might become a little simpler. But, the high cost of the reader might hinder its quick development. Anyways soon or later this mass storage optical device is going to replace the DVD & let the user experience a world high quality & disc space (Quality & Quantity ensured) with high level of security and privacy ensured.