Re: [hylafax-users] "USE 2-DMR" based only on info/fax-no data?

[Dmitry Bely <dbely@mail.ru>]

Giulio Orsero <giulioo@pobox.com> writes:

> Linux Red Hat 61. HylaFAX cvs 20001022
> 
> - Fresh install (no files in info/ )
> - Same doc sent twice to the same remote fax no.
> - 1st time 1-D was used, 2nd time (info/fax-no says
> supports2DEncoding:yes) 2-D.
> - delete info/fax-no, fax, 1-D again
> 
> So it seems HylaFAX decides to use 2-D based on the info file and not on
> what the remote fax says. Is this the intended behavior? Why? 

Because Hylafax is just a file->/dev/modem copier, not the real fax
software :-) It's unable to encode data "on the fly" (which would possibly
require the multithreaded design) and so tries to predict which coding
scheme is supported by the remote *before* the call is placed. For unknown
destinations 1-D MR is used first (which is mandatory for all fax
machines), and then (after successful connection) information about actual
capabilities is stored into the info database. Next calls will use better
coding if possible.

Drawbacks of this method are so obvious, that I won't even mention
them. Just a small note: it also does not allow to implement optional high
res modes (more than "fine" 196 x 204 dpi)

> 1st transmission, 1-D
> [12575]: REMOTE best rate 14400 bit/s
> [12575]: REMOTE max page width 2432 pixels in 303 mm
> [12575]: REMOTE max unlimited page length
> [12575]: REMOTE best vres 7.7 line/mm
> [12575]: REMOTE best format 2-D MR    <=====
> [12575]: REMOTE best 0 ms/scanline
> [12575]: USE 14400 bit/s
> [12575]: USE 0 ms/scanline
> [12575]: SEND file "docq/doc1.ps;01"
> [12575]: USE page width 1728 pixels in 215 mm
> [12575]: USE unlimited page length
> [12575]: USE 7.7 line/mm
> [12575]: USE 1-D MR   <=====
> 
> 2nd transmission, 2-D (info/fax-no says 
> [12593]: REMOTE best rate 14400 bit/s
> [12593]: REMOTE max page width 2432 pixels in 303 mm
> [12593]: REMOTE max unlimited page length
> [12593]: REMOTE best vres 7.7 line/mm
> [12593]: REMOTE best format 2-D MR   <=====
> [12593]: REMOTE best 0 ms/scanline
> [12593]: USE 14400 bit/s
> [12593]: USE 0 ms/scanline
> [12593]: SEND file "docq/doc2.ps;41"
> [12593]: USE page width 1728 pixels in 215 mm
> [12593]: USE unlimited page length
> [12593]: USE 7.7 line/mm
> [12593]: USE 2-D MR     <=====

Hope to hear from you soon,
Dmitry




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