Re: [hylafax-users] JBIG, v.34, ColorJPEG

[Lee Howard <faxguy@xxxxxxxxxxxxxxxx>]

Ron Pettis wrote:

> Just recently replaced a "receiving-only" pool of color V.34 fax machines with some USR Sporsters on a Fedora Core 5 system running Hylafax 4.3.0 in Class 1.  The drives are a software RAID1.
>
> It's been running beautifully for 2-3 weeks so we've opted to purchase Rockforce Duo+'s in order to once again take advantage of the v.34 speeds/compression.  We also figure that at the same time we'll implement the color capabilities of the previous setup.  (Our external sales force uses the color capability of their fax machines [HP 1240 Fax Machines] when faxing to us).
>
> But before we install the new boards and go down this path, we've got a few questions.
>
> Our existing setup receives the standard tiff-fax, does a tiff2pdf on it, and emails the PDF (via mSMTP) to our email server.
>
> We're using the stock libraries (libtiff, etc) that ship with the distro, no modifications to any libraries.
> My research on this indicates that we'll need to make changes to libraries and patch them, etc., as in:
>
> http://www.hylafax.org/content/Handbook:Advanced_Server_Configuration:JPEG_and_JBIG_Faxing
>
> I'm not sure I understand the step-by-step procedures to accomplish this.  Can someone steer me in a procedural direction what I must do?  The more research I do on this, the more confusing it seems to get.
>  

Those words in the referenced handbook are mine and were taken from the 
HylaFAX HOWTO which can currently be found here:

 http://hylafax.sourceforge.net/howto/install.php#ss2.5

There are still some things there that need to be updated, for example, 
statements of "CIELAB" need to be changed to "ITULAB" instead.

A general step-by-step procedure is this:

1) patch libjpeg, build, and install it.  This will most likely require 
that you install the patched libjpeg in a peculiar way to coexist 
happily with your existing libjpeg, or that you replace the existing 
libjpeg with it and rebuild all libjpeg-dependent packages against the 
patched library.  If the system is fax-dedicated then I just do a 
minimal install and remove anything that depends on libjpeg... and then 
I do the patch/build/install procedure for libjpeg.  libjpeg is a very 
slow-moving development, and although I expect the ITULAB JPEG support 
to eventually make it into the source repository in some form for their 
v7 release, for the foreseeable future patching libjpeg will always be 
required... unless your distribution patches it for you... or unless 
changes in libtiff make this step unnecessary.

2) install JBIG-KIT

3) patch libtiff, build, and install it (--with-jbig).  The next libtiff 
(after 3.8.2) release will have JBIG support built-in (all you'll need 
to do is ./configure --with-jbig), but for now the JBIG patch is still 
required.  It will also need to be patched for ITULAB JPEG support.  The 
provided patches will not ever be integrated into libtiff as they are 
because libtiff's JPEG support will be reworked entirely by the libtiff 
developers (apparently for their v4 release)... and apparently ITULAB 
JPEG support will come differently than the way done with the patches, 
and so it may be possible that this future libtiff development will 
deprecate the need (at least for HylaFAX users) to patch libjpeg.

There are some shortcomings to the libtiff ITULAB patch.  The one that 
is foremost on my mind is the incapability that tiffcp has to work with 
ITULAB JPEG TIFF files.  Something broke the patch's tiffcp 
functionality between 3.7.2 and 3.8.2.  tiff2ps, however, does work, and 
I don't intend on fixing tiffcp - since the libtiff developers are 
reworking things in the not too-far-distant future.

4) install HylaFAX, use Class 1/1.0, and configure the modem with 
"Class1ColorJPEGSupport: yes".  I would recommend using HylaFAX+ instead 
of HylaFAX from hylafax.org as there have been some changes to this 
stuff since I moved my work to sourceforge.  I think that the 
hylafax.org maintainers eventually ported all of the changes into the 
hylafax.org codebase, but honestly, I'm not certain of that or if 4.3.1 
has even been tested at all with color fax receiving.

The newest versions of these patches for libjpeg and libtiff can be 
found in SRPMs that are found here:

   http://sourceforge.net/project/showfiles.php?group_id=148904

> Will a JPEG'd-tiff convert to PDF with tiff2pdf?  Will I instead need to tiff2ps and ps2pdf?  And will Adobe Acrobat Reader 6.0/7.0 display it correctly?
>  

No, yes, and it depends.  I assume that you refer to libtiff's 
tiff2pdf.  Although it does properly convert the JPEG'd TIFF into PDF it 
leaves the ITULAB JPEG data in the same colorspace (merely changing the 
TIFF wrapper for a PDF one), and I've not yet seen any PDF viewer that 
can properly view ITULAB JPEG.  However, the bin/tiff2pdf script that 
comes with HylaFAX *will* convert ITULAB JPEG TIFFs into viewable PDFs - 
because, yes, it uses tiff2ps and then ps2pdf.  All PDF viewers that I 
have used, including Acrobat Reader, can view those resulting PDFs 
(tiff2ps+ps2pdf).

> Also, what modem config file changes would be recommended, knowing our exclusive use of HP 1240's as senders?
> Are the elements at the following site still relevant?
>
> http://www.hylafax.org/content/Handbook:Basic_Server_Configuration:Modem-specific_Guidance
>  

I've given you the config file changes needed and I can't comment on the 
hylafax.org handbook, as I don't read or maintain it, but the HOWTO that 
I indicated above augmented by the content of this e-mail should be the 
most accurate reference at the moment.

> The goals are to once again have the following features:
>
> 1) Receive at the v.34 speeds
> 2) Use the modern compressions/error corrections
> 3) Honor the color capability and send color PDF's

I think that you mean *receive* color faxes and *send* them as color 
PDFs to the receipient.  HylaFAX currently cannot *send* color faxes (it 
can *receive* them).  The *sending* of color faxes is on my to-do list, 
but right now it's not very high on the priority list.

Thanks,

Lee.


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