Many things

From: Eric Smith <eric_at_brouhaha.com>
Date: Sun Jan 30 23:08:25 2005

Randy wote:
> DjVu has a hugely more efficient scheme for their files, DjVu files of the
> same document are a fraction of the size of PDF's.

Having researched this somewhat a year ago, I'm going to (partly/mostly)
disagree. DjVu files are only slightly smaller if they use lossless
compression. By default, DjVu uses lossy compression, which is
significantly smaller. But for archival purposes, I *much* prefer the
lossless coding. Should I decide to OCR the documents at a later date,
having the lossless bits is much better. The lossy encoding is designed
to throw away stuff that has minimal effect on the human visual system
when not under close scrutiny, but that isn't necessarily stuff that won't
help an OCR program.

Also, G4 coding is a much better known standard. If fifty years from
now someone has to build their own drive to read an ancient CD, and
discovers that it's full of compressed images, I think they've got a
much better chance of being able to decode G4 images since the format
is well-documented and well-known.

However, if someone else went to the trouble of archiving a bunch of
old computer docs in DjVu, I'd still thank them for doing so, as it
is quite obviously much better to have the docs in DjVu format that
to not have them at all.

Eric
Received on Sun Jan 30 2005 - 23:08:25 GMT