Re: dual layer DVDs

From: Ken Bawcom (email suppressed)
Date: Tue May 15 2007 - 16:25:56 PDT

If you are copying an existing DVD, the compression/encoding has
already taken place, and there is no advantage to copying it over at a
higher bit rate. A bit-for-bit copy would produce as good a picture
quality as was possible, equal to the original. To take advantage of
the reduced compression/higher bit rate that a DL disc allows, you
would have to do the encoding from the original source at the higher
bit rate.

A DL disc would allow you to record almost as much material at an XP
bit rate as a SL disc will allow at an SP bit rate. Note that a DL disc
has a little less than twice the storage capacity of an SL disc. Note
also that if you record at a bit rate exceeding DVD specs, it may not
play back on some players, especially older ones. That generally will
not be a problem at the XP bit rate. There will still be some
compression of the video at an XP bit rate, but you can record LPCM
uncompressed audio with it.

Ken B.

Quoting gyoungblood <email suppressed>:

> Frameworkers,
> I'm thinking to purchase a dual layer DVD read-write drive on the
> assumption that it will allow me to copy DVDs with less compression
> than single layer. Am I right? If so, what does "less compression"
> mean? If I copy a dual layer disc to another dual layer disc, will
> there be no compression? Are there any other problems with dual layer
> copying? Can anyone recommend a website that explains all this?
> Gene Youngblood
> Department of Moving Image Arts
> The College of Santa Fe
> 1600 St. Michael's Drive
> Santa Fe, NM. 87505 USA
> Vox: +1.505.473.6406
> Fax: +1.505.473.6403
> Office: email suppressed
> Home: email suppressed
> __________________________________________________________________
> For info on FrameWorks, contact Pip Chodorov at <email suppressed>.

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For info on FrameWorks, contact Pip Chodorov at <email suppressed>.