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Victoria Video Club

Bulletin Vol 64 No 8 - Page 2

MAY 2005

 

DVD FACTS
YOU NEED TO KNOW
Reference: http://dvddemystified.com/dvdfaq.html

DVD Recorders are not 'exactly' VCRs. They both have a tuner, A/V inputs and outputs, and can be programmed to record shows. But because they must encode video (MPEG) and audio (Dolby Digital, MPEG, or PCM), create navigation menus, and work with different types of disks you need to expect that there will be some new things to learn. The following will help as you consider a purchase.

There are five types of DVD disks:

 
Type
Estimated Life (Years)
1
DVD-R
DVD-R *
20-250
100+
2
DVD-RW
25-100
3
DVD+R
DVD+R *
20-250
100+
4
DVD+RW
 
25-100
25-100
5
DVD-RAM
 
20-250
100+

* using advanced dyes

Almost all of the disks sold today are single-layer (4.7 GB capacity), but dual-layer (9.4 GB capacity) is becoming available now. Dual-layer disks double recording capacity. So you could think of there being 10 'types' of DVD disks.

Some DVD recorders can read and write just a few formats, (e.g. Morris' Panasonic recorder can use three types: DVD-R 4.7 GB, and DVD-RAM 4.7 and 9.4GB). High priced recorders can read and write more, or all the types of disks. Check to see what disks you need for the recorder that you are considering.

Another caution: the recorder may have a list of media that have been specifically tested to work with (e.g. Maxtor, Verbatim, etc). If you choose to ignore these recommendations then purchase a small number of disks and TEST to see that they work ok.

Pressed DVDs (i.e. commercial DVDs) are estimated at 50-300 years. Standard dye-based DVD-R and DVD+R are estimated at 20-250 years. Advanced dye-based disks, that use phthalocyanine (clear) and azo (dark blue), are estimated at 100 years and more.

Phase-change erasable formats (DVD-RAM, DVD-RW, and DVD+RW) are estimated at 25 to 100 years.

For comparison, magnetic media (tape and disks) last 10 to 30 years.

 

But remember that there is little difference between a disk that cannot be read because it is technically obsolete, and one that has physically deteriorated. So you may not need that disk that is good for 300 years.

Some DVD disks are now coming out with claims to be "scratch" resistant. Since DVD disks are not in a cartridge, the recording surface is exposed and can be damaged by scratching, finger-prints, or even by ultraviolet light. You may want to consider these "tougher" disks if you like the idea of 'kid-proofing' them.

And consider recording speed if you are expecting to produce lots of DVDs. Range is 2x, 4x, 8x or 16x.

  • 2x recorder can write a 4.7 GB DVD in 30 minutes, and

  • 4x recorder in about 15 minutes.

Picture Quality

Similar to tape recording, you can choose to record so that you get either the best picture quality or the most amount of footage on a disk—with a few stops in-between. Best mode is achieved by selecting 1 hour of recording on a single-layer disk (2 Hours on a dual-layer disk). From there you can increase to 6 or 8 hours of recording with decreasing visual and audio quality.

What Do You Want to Do?

  • Archive home movies

    o Analog (VHS, 8mm, etc)

    Some offer video processing designed to "Clean up" an analog signal before putting it on DVD. For example: 3-D comb filter and time based correction, noise reduction or video equalization.

    Look for S-VHS connector

    o Digital (MiniDV, Digital 8)

    Look for i.Link (a.k.a Firewire or IEEE 1394) input connector.

  • Record TV broadcasts

    o VCR Plus and Guide Plus

    o Hard drive allows large amount of shows to be stored.

  • Video Editing

    o Look for models with internal hard drives

    o This topic is beyond the scope of this handout…talk with sales staff that you trust.