vigra_impex bug creates 'arithmetic coded' JPEG output

[Bruno Postle]

vigra_impex has a bug which effectively means all JPEG output is 'arithmetic coded' (rather than huffman coded) if the version of libjpeg supports it.

This is a problem as arithmetic coding isn't very portable, e.g. the enblend 4.0 in fedora f15 is creating these JPEGs whenever JPEG is selected for output.

The upstream vigra fix is these two changesets:
http://www.informatik.uni-hamburg.de/~meine/hg/vigra/rev/e54137017af7
http://www.informatik.uni-hamburg.de/~meine/hg/vigra/rev/f5e29e0bdfe0

It probably isn't worth backporting all this to enblend, a simple fix is to just comment out src/vigra_impex/jpeg.cxx line 421.

[Yuv (yuv)]

I just noticed that you don't have write access to enblend's repo. fixed it. you now have admin privileges on the enblend project as well.

[Matthew Petroff (matthewpetroff)]

This issue is still in the trunk. I ran into it producing test builds with the new graph-cut seam generator. I had to change src/vigra_impex/jpeg.cxx line 421 from "info.arith_code = TRUE;" to "info.arith_code = FALSE;" to get the JPEGs produced to open in most software.

[Bruno Postle (brunopostle)]

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On Tue 21-Jun-2011 at 13:38 -0000, Yuv wrote:
>I just noticed that you don't have write access to enblend's repo.
>fixed it. you now have admin privileges on the enblend project as well.

Thanks, I committed the one line workaround.

  status fixcommitted

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[jay armstrong (jayarmstrong)]

what version of enblend was this released in?

I'm trying to track down a bug but can't tell if it's this one. Thanks!

[tduell (tduell-iinet)]

Hello Jay,

On Tue, 22 Oct 2013 04:23:25 +1100, jay armstrong
<email address hidden> wrote:

> what version of enblend was this released in?
>
> I'm trying to track down a bug but can't tell if it's this one. Thanks!
>
I think the problem first arose in 2011 when the patent on the arithmetic
coding algorithm expired and libjpeg-turbo was adopted by Fedora (and
maybe others), and Enblend 4.0 was the current release (since Dec 2009).
Enblend 4.1 was released in Dec 2012.

An error message relating to the problem was like this...
"loading failed: Error interpreting JPEG image file (Sorry, there are
legal restrictions on arithmetic coding)."

Hope that helps.

Cheers,
--
Regards,
Terry Duell