DVD Name and Formats

DVD stands for just DVD. However many people refer to DVD as the Digital Versatile Disc or Digital Video Disc. It should be noted that discs for the new DVD movie players are being referred to as DVD; whereas the discs for the computer drives are being referred to as DVD-ROM.

Toshiba/Time Warner are using two half-thickness (0.6mm) discs bonded together for a double sided DVD standard disc format. The standard also allows for 3M’s dual layer “2P” technology to be used.

The following is a summary of the most common DVD capacities:

• DVD-5 4.7 GB (Single Layer Single Side)
• DVD-9 8.5 GB (Dual Layer Single Side)
• DVD-10 9.4 GB (Single Layer Double Side)
• DVD-17 17.0 GB (Dual Layer Double Side)

The new DVD discs can store from 4.7 GB (single sided, single layer) up to 17.0 GB (double sided, dual layer per side for a total of 4 layers of information). Each layer of data on a DVD disc will allow up to 133 minutes of full motion MPEG-2 video. This amount of playing time will allow 95% of all movies to be contained on one side of a disc. This new disc will also support a variable bit data rate which will increase the quality of digital video playback thanks to a substantial buffer memory. The new DVD movie players are also capable of seamless switching between the two layers of information on each side of the disc.

Media Source

DLT (Digital Linear Tape) is used as “source” to send in the large quantity of data to be mastered into DVD. DLT tape cartridges are slightly larger than 8mm tape cartridges but smaller than VHS cartridges. There are different densities of DLT tape with the highest capacities holding up to 20GB per tape (uncompressed). Other types of tapes and transfer media are under development to support DVD.

Cutting a full 4.7GB single layer of a DVD disc today at the fastest encoding speeds available takes over 90 minutes. As the mastering software and hardware are improved, this time will decrease. Remember, a full DVD disc could contain up to four mastered layers of information. A mastering cut must be done for each layer of information put onto a DVD disc. Therefore, as the number of layers of information increases, so will the mastering cost and time.

Some of the problems that threaten to delay the quick acceptance of DVD in the marketplace are the following:

• COPY PROTECTION
• REGIONAL CODING
• LICENSING
• TODAY’S CD-Rs MIGHT NOT PLAY ON DVD DRIVES

Due to the change in wavelength on the playback laser for DVD players today’s CD-Rs might not play on some DVD drives. This could be a serious problem for the quick acceptance of DVD in the marketplace. Changing the reflectivity on newly manufactured CD-Rs would solve this problem. However this would still leave many thousands or millions of unplayable CD-Rs in the market. Some manufacturers are planning on putting two laser optical pickups on their new DVD drives. One would be at the old wavelength and would be able to play today’s CD-Rs. The other would be at the new wavelength and would play DVDs. This would of course add cost to the drive however it would completely solve this backward compatibility issue.

The file structure on a DVD will be Micro UDF (Universal Disk Format) initially combined with ISO 9660. Eventually Micro UDF will become the standard file format used for DVD. The Micro UDF file format will extend and modify what is currently possible with ISO 9660.

The decision to standardize on a single high density digital (video) disc (which has the potential to be a $50 billion a year market) is very good news for computer, consumer electronics, and entertainment companies. Until the compromise was reached, DVD projections were for a slow, limited roll-out, with the new format not really taking hold until the end of the decade. Now, post-convergence sales projections are more optimistic.

eDocPublish.com manufactures DVD discs based on the specification available to date.

eDocPublish.com has Multiple lines that manufactures DVD and DVD-ROM discs.