[sane-devel] Scanner-based compression for Fujitsu FI-5900c on 1.0.27?

Wes Rishel wrishel at gmail.com
Tue May 15 00:08:24 BST 2018

The 5900 has a mode where JPEG compression is done in the Fujitsu scanner
backend, thus reducing the bandwidth used in the USB2.0 connection to the
Ubuntu system.

I have seen this working on an Ubuntu 12-based computer. I understand that
fujitsu.c from SANE 1.0.24 was modified by the programmer who was
volunteering for this non-profit back then, but I am not sure that I have
an exact copy of that C file.

I am trying to get the system working on a new computer with Ubuntu 16.04.
We have modified the fujitsu.c file but we are getting an error message. I
don't have the exact message but it was to the effect that an option was
not enabled.

As such I am hoping to get help with these questions:

- Is it true that the only changes necessary to enable the in-scanner JPEG
compression are in fujitsu.c?

- Can someone tell me exactly what those changes are for 1.0.27? Just to
confirm, I think this is build 133.

I have been assuming that this was what required, but perhaps there is
something more?

At line 667 change:

#define SANE_FRAME_JPEG 0x0B


#define SANE_FRAME_JPEG 0x0B
/*#define SANE_JPEG_DISABLED 1*/

- At runtime the option being used is in the scanimage arguments is

       --compression JPEG

   Is any other option needed to enable scanner-side JPEG compression?

- Is the --mode color option required for scanner-side JPEG compression on
this scanner?

Thanks in advance.


Wes Rishel
Retired Healthcare Computer Nerd


"Rainbows are just to look at, not to really understand."

Children's Beguiling Ideas About Science        Proffered by T. K. Cassidy
- Children's Librarian        tkc at kuentos.guam.net
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