Brief introduction to rewritable DVD format: DVD-RAM, DVD-RW and DVD+RW

by Dr X Zhu PhD. in Feb 23, 2003

Author Email: itreviews@ntlworld.com You may copy this document but do keep content complete.

1. Recordable and Rewritable DVD formats in the market

There are three rewritable DVD formats: DVD-RAM, DVD-RW, and DVD+RW, and two write once format DVD-R, and DVD+Ravailable in the market.

1.1 DVD-RAM

DVD-RAM came from the computer industry, where high-speed random access is vital. This gives the format certain advantages over the other two recordable standards (DVD-RW and DVD+RW): users can record one programme while simultaneously watching another - on the same disc. This is thanks to the access speed of DVD-RAM, and is a function that RW and +RW cannot duplicate.
DVD-RAM media could be rewritten more than 100,000 times and were a great way to archive large amounts of data or video, which compares favourable to DVD-RW / +RW 's 1000 times, while the cost of the media is more or less the same level.

1.2 DVD-RW

DVD-RW format gives users the ability to record, erase and then record again up to 1,000 times. DVD-RW discs can be read in many DVD players and DVD-ROM's but not all. This format does not support efficient encoding of video using variable bit rates. This limits the recording speed to only 1x and it can take a good 1 or 2 hours to write a DVD movie.

1.3 DVD+RW

DVD+RW format was introduced by the DVD+RW Alliance which are formed by Dell, HP, Mitsubishi Chemical, Philips, Ricoh, Sony, Thomson Multimedia and Yamaha. The DVD+RW format was designed to deliver the best performance available with the best possible compatibility. However the exact trouble with DVD+RW is its compatibility. The media has low reflectivity, which means that it's not nearly as compatible with legacy DVD-ROM drives and DVD movie players as the high-reflectivity DVD-R media. This makes sharing data or movies with friends via DVD+RW potentially problematic.

1.4 DVD-R

DVD-R discs are write-once medium, and they are very similar to DVD-ROM's. Thanks to these similarities, DVD-R is treated like a regular DVD in most (though not all) standard DVD player and PCs - including Apple Macs.

2. Cost of different format medium

DAV-RAM cartridge costs around £10, which is almost the same as DVD-RW / +RW. DVD-R is the cheapest, costs only ~ 80p each.

3. Which format to choose

Use DVD-R if you want to create DVDs for others to play on their computers or home-entertainment systems.
Use DVD-RAM for regular backing up of large amount of data.
For other format, wait till compatible issue resolved.

For more information about different format of rewritable DVD format and comparison click here.

Acknowlegement

Thanks Allcam Mobile Products Limited for donating a USB2.0 external DVD burner.