Re: [hylafax-users] Poor PDF Quality

[Lee Howard <faxguy@xxxxxxxxxxxxxxxx>]

ECM is fax error correction.  It causes the sender to retransmit 
portions of image data that are received corrupted at the receiver.

Attached are two faxes of the original document that you provided.

"fax.pdf" is the fax sent in normal resolution with a default 
configuration using ECM.  Notice that the image corruption does not 
exist on it as you showed in your sample before.

"fax2.pdf" is the fax sent in normal resolution but with 
"DITHERING=libtiff-fs" in etc/FaxModify (currently only a HylaFAX+ feature).

Between these two and the sample that you sent before you should be able 
to see the difference in what ECM provides as well as the difference 
that is gained from an alternative dithering approach.

Thanks,

Lee.


breedish wrote:
> Greetings, Lee.
>
> Here is pdf itself and ps file. Could you tell me what is ECM communication in 2 words?
>
> 26.07.08, 22:47, "Lee Howard" <faxguy@xxxxxxxxxxxxxxxx>:
>
>   
> > breedish wrote:
> >     
> > > Today i setup hylafax server and send PDF file, but a quality is very bad (in attach you can see the quality).
> > >       
> > I have a hard time believing that the attached image was generated by 
> > the session which log you provided.  There looks to be image errors that 
> > can only happen in non-ECM communication.
> > Can you provide me a copy of the original source document?
> > Thanks,
> > Lee.
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>

Attachment: fax.pdf
Description: Adobe PDF document

Attachment: fax2.pdf
Description: Adobe PDF document