Re: [Jpeg-users] libjpeg 6c ?

[Guido V. <gu...@jp...>]

Hi Mathieu

The most important aspect of that v7 update will be to introduce
new features in the core of the JPEG system, and that core is the
DCT!  This has to be understood first:  The primary aspect is to
utilize the fundamental DCT properties to a more appropriate
degree than has been done before in image coding in general,
and everything else is secondary!

You must understand that all established image compression research
and development is actually going in wrong directions, and the
reason for this situation is that the DCT and its fundamental
properties are not understood properly.  There is a common lack
of understanding the basic image coding principles - I have until
today not come across a single person who would understand the
essence of the DCT for image coding!  And I can tell you that I
have met and communicated with lots of so-called "experts" in this
field - including the original JPEG and MPEG authors!  And no one
of them has understood the DCT and its potential!  So that is the
primary and essential goal to achieve.
Without proper understanding and utilizing the DCT there can be
no real progress in image coding - all other attempts which we see
today are mistakes and will fail, due to misunderstanding of and
deviating from the true DCT.
JPEG as we know it today uses only a tiny subset of the full DCT
potential, and v7 starts to extend the features to a more
appropriate degree.  (It lays foundation for other important
features to come later...)

> By the way do you consider merging the lossless patch from Ken
> Murchison in v7 at all ?

You mean the lossless mode of the original JPEG spec?
There is a reason that it has not found noticeable application
in practice.  It is not seamlessly integrated with the usual
DCT processing mode.  With proper understanding of the DCT you
can provide a lossless mode which is seamlessly integrated with
the DCT mode.  This is one of the features possible with the
new direct DCT scaling functions as described on my site and in
my JPEG-Plus proposal, which is actually ignored at the official
committees because they are invested in bogus developments.

Regards
Guido Vollbeding
Organizer Independent JPEG Group