From: D. Starner (shalesller@writeme.com)
Date: Wed Nov 26 2003 - 08:05:21 EST
> In the case of GIF versus JPG, which are usually regarded as "lossless"
> versus "lossy", please note that there /is/ no "orignal", in the sense
> of a stream of bytes. Why not? Because an image is not a stream of
> bytes. Period.
GIF isn't a compression scheme; it uses the LZW compression scheme, like
Unix compress, which is a stream of bytes compressor. Also, if I take my
data and encoded it as bytes and stick it into a GIF file with an arbitrary
palette, I can get back exactly that data. But if I encode my data as 9 bit
chunks and interprete those as Unicode character points (9 bits, because
10 bits would get us undefined code points and 16 would get us surrogate
code points), and I emailed it to someone, and the mailer automatically
compressed it, I wouldn't consider it lossless if it wouldn't decompress
at the other side. And enough stuff in the real world will barf on combining
characters, or at least perform suboptimally, that changing the normalization
scheme could really cause problems.
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