[mythtv-users] OT: RE: which dvd?

Michael Heironimus mkh01 at earthlink.net
Sat Jun 9 13:46:26 UTC 2007


On Sat, Jun 09, 2007 at 12:39:01AM -0700, Justin The Cynical wrote:
> Actually, I've wondered about this...  Why + over -?
> 
>  From what I have found online, for maximum compatibility, one would 
> want to stick with - as that is the closest to a pressed DVD.
> 
> Why would someone pick one over the other?

As I recall, both types are very similar from a technical stand. The
different in reflectivity is only a few percent, so a device that can't
read +R reliably for that reason is likely to also be picky about -R
media, maybe even pressed disks with smudges. Both R formats are more
reflective than either RW format, and I think both dual-layer recordable
formats have about the same reflectivity as RW.

The place where you start running in to real compatibility differences
is usually the book type. There is a certain spot on the disc that has a
flag identifying the media type. For DVD-R the type is factory-set to
DVD-ROM, just like a pressed DVD. For DVD+R it's written during the burn
and many (most?) burners set it to DVD+R. However, if you do a web
search for "bitsetting" you'll find a lot of tools and tutorials for
overriding that and flagging DVD+R media as DVD-ROM during the burn.
That solves a lot of problems with older devices - I have two DVD-ROM
drives from around 2000 that only recognize DVD+R if you set the book
type to DVD-ROM.

Originally, the difference in compatibility between high- and
low-quality media was often greater than the difference between +R and
-R formats. Today things are a lot easier because the media has become
more of a commodity and consumers now expect hardware manufacturers to
support recordable discs.

Personally, I use DVD+R. Not because of compatibility, everything I have
works equally well or equally badly with both, as long as I bitset the
+R burns. I use DVD+R because when I needed to buy media I was able to
get known-good +R discs cheaper than -R. When there was a sale I bought
a spool of DVD+R marked "made in Japan", which almost always means
Taiyo-Yuden. The DVD-R discs in the same sale were all made in Taiwan so
I couldn't tell if they were from good manufacturers or not. I don't
burn much, so a spool lasts a very long time.

This does bring back memories.... Everybody expected it to be another
VHS-vs-Betamax fiasco, with the big losers being the consumers. During
the "format wars" people were even bringing up silly things like DVD+R
being better because you could burn it at 2.4x and DVD-R only burned at
2x. Funny how things never really settled out. Both formats were good
enough on compatibility, and the drive manufacturers started selling
dual-format burners early enough that the market didn't have to choose.

-- 
Michael Heironimus


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