

Re: do vector graphics enhance our concept of self?

From: David Woolley <david@djwhome.demon.co.uk>
Date: Sat, 27 Jul 2002 10:11:48 +0100 (BST)
Message-Id: <200207270911.g6R9BnQ05298@djwhome.demon.co.uk>
To: w3c-wai-ig@w3.org

> Surely it must be plain that with all the open source productivity available
> a concerted effort to either get the jpeg source released, reverse engineer,
> or create a new source is a reasonable project?

The JPEG source (at least that used by all the common tools, i.e. without
the patented arithmetic coding) has been released from the beginning!

The basic library is what ghostscript uses for JPEG like images, what
current TIFF tools use for such images, and what many other things 
probably use.  TIFF is a flexible format, and therefore probably
already allows an alpha channel to be added (although I haven't
dug out the specification to confirm that this can be done and the
alpha channel can have a different coding, to allow a binary channel
to be expressed accurately and compactly).

Outside the actual JPEG format, JPEG is normally referred to as DCT
encoding (relating to the Discrete Cosine Transform coding that it uses),
but both PostScript (PDF) and TIFF DCT are essentially JPEG in a 
different wrapper.

I repeat that the reason for lack of support is almost certainly that
it would exceed the technical level of most authors, who are probably
still using JPEG for screen shots (some modern over designed web pages,
probably actually need JPEG!) and GIFs for faces.  As the market is defined
by the market for the browsers, not by that for the authoring tools, there
is no real pressure from the market to do any better.

I've noticed things like people who turn up the quality level to maximum
all the time; that doesn't really indicate much sophistication amongst
users of JPEG.

The following line comes from the README for libjpeg version 6b of 1998.


There are patent issues, but no one seems to use the patented options.
The library doesn't imlement all the features, but some are probably
not implemented by any browser either.
Received on Saturday, 27 July 2002 05:20:21 GMT
