DVD

DVD stands for Digital Versatile/Video Disc, DVDR stands for DVD Recordable and DVDRW for DVD Rewriteable.

If you use audio/music CDs or regular DVD-Video discs, then you will know what a recordable DVD looks like.
A recordable DVD stores up to 2 hours of very good quality DVD-Video, including several audio tracks in formats like stereo, Dolby Digital or DTS and also advanced menu systems, subtitles and still pictures that can be played by many standalone DVD Players and most computer DVD-ROMs.

If you choose to lower the video quality it is possible to store several hours video on a recordable DVD using low bitrates and low resolution with video quality more like VHS, SVHS, SVCD, CVD or VCD. It is also possible to have up to 4.37* GB ordinary data or mix DVD-Video and data on a recordable DVD that can be played by most computer DVD-ROMs.

There are three competing DVD Recording standards:

• DVD-R/DVD-RW and

• DVD+R/DVD+RW have pretty similar features and are compatible with many standalone DVD Players and most DVD-ROMs while
  

• DVD-RAM has less DVD Player and DVD-ROM compatibility but better recording features.
  

DVD-R and DVD-RW

• DVD-R was the first DVD recording format released that was compatible with standalone DVD Players.

• DVD-R is a non-rewriteable format and it is compatible with about 93% of all DVD Players and most DVD-ROMs.

• DVD-RW is a rewriteable format and it is compatible with about 80% of all DVD Players and most DVD-ROMs.

• DVD-R and DVD-RW supports single side 4.37 computer GB* DVDs (called DVD-5) and double sided 8.75 computer GB* DVDs  (called DVD-10).
  
  
  DVD+R and DVD+RW
  DVD+R is a non-rewritable format and it is compatible with about 89% of all DVD Players and most DVD-ROMs.
  DVD+RW is a rewritable format and is compatible with about 79% of all DVD Players and most DVD-ROMs.
  DVD+R and DVD+RW supports single side 4.37 computer GB* DVDs called DVD-5) and double side 8.75 computer GB* DVDs called DVD-10).
  These formats are supported by the DVD+RW Alliance.
  
  DVD+R DL
  DVD+R DL or called DVD+R9 is a Dual Layer writeable DVD+R. The dual layered discs can hold 7.95 computer GB* (called DVD-9) and dual layered double sides 15.9* computer GB (called dvd-18).
  
  DVD-R DL
  DVD-R DL or called DVD-R9 is a Dual Layer writeable DVD-R. The dual layered discs can hold 7.95 computer GB* (called DVD-9) and dual layered double sides 15.9* computer GB (called dvd-18).
  
  DVD-RAM
  DVD-RAM has the best recording features but it is not compatible with most DVD-ROM drives and DVD-Video players. Think more of it as a removable hard disk. DVD-RAM is usually used in some DVD Recorders.
  

DVD Sizes

The DVD sizes can be a bit confusing. There are basically 4 different DVD Sizes,

DVD-5, holds around 4 700 000 000 bytes and that is 4.37 computer GB where 1 kbyte is 1024 bytes* . DVD+R/DVD+RW and DVD-R/DVD-RW supports this format. Also called Single Sided Single Layered. This is the most common DVD Media, often called 4.7 GB Media.

DVD-10, holds around 9 400 000 000 bytes and that is 8.75 computer GB. DVD+R/DVD+RW and DVD-R/DVD-RW supports this format. Also called Double Sided Single Layered.

DVD-9, holds around 8 540 000 000 bytes and that is 7.95 computer GB. DVD+R supports this format. Also called Single Sided Dual Layered. This media is called DVD-R9, DVD-R DL, DVD+R9, DVD+R DL or 8.5 GB Media.

DVD-18, holds around 17 080 000 000 bytes and that is 15.9 computer GB. DVD+R supports this format. Also called Double Sided Dual Layered.

* In the computer world is 1 KB data = 1024 bytes so 4 700 000 000 bytes / 1024 = 4 589 843KB / 1024 = 4482MB / 1024 = 4.37GB. See section 3.3 in the DVDDemystified FAQ here.


DVD+R/DVD+RW/DVD+R DL and DVD-R/DVD-RW exact sizes
DVD-R/DVD-RW = 4 706 074 624 bytes ( 4488 MB )
DVD+R/DVD+RW = 4 700 372 992 bytes ( 4482 MB )
DVD+R DL = 8 547 993 600 bytes ( 8152 MB )

When DVD technology first appeared in households, users were simply popping DVD discs into their DVD players to watch movies ? an attractive option to the then-conventional VCR. But just as compact disc technology evolved so that users could record and erase and re-record data onto compact discs, the same is now true of DVDs.

With so many different formats ? DVD+R, DVD+RW, DVD-RAM, DVD-R, DVD-RW, DVD-ROM ? how do users know which DVD format is compatible with their existing systems, and why are there so many different formats for DVDs? The following information sheds some light on DVD's different flavours, the differences between them and the incompatibility issues that the differing technologies have sprouted.

The crucial difference among the standards is based on which standards each manufacturer adheres to. Similar to the old VHS/Beta tape wars when VCRs first hit the markets, different manufacturers support different standards.

DVD+R and DVD+RW
DVD+R and DVD+RW formats are supported by Philips, Sony, Hewlett-Packard, Dell, Ricoh, Yamaha and others.

DVD+R is a recordable DVD format similar to CD-R. A DVD+R can record data only once and then the data becomes permanent on the disc. The disc can not be recorded onto a second time.

DVD+RW is a re-recordable format similar to CD-RW. The data on a DVD+RW disc can be erased and recorded over numerous times without damaging the medium.

DVDs created by a +R/+RW device can be read by most commercial DVD-ROM players.