Re: [hylafax-users] Hrm.... XX ms/scanline values

[Lee Howard <faxguy@xxxxxxxxxxxxxxxx>]

On 2003.10.15 02:43 An Intrepid HylaFax User wrote:
> I realise the magic ITU documents refer to this nomenclature, but...
>
> Are there actual timing constraints which result from such things:
>
> Oct 15 04:45:27.35: [32647]: REMOTE best 10 ms, 5 ms/scanline
>                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
> As in, if scanlines of fax image data doesn't arrive "in time" to meet
> those
> values, things go badly?

No, it's the other way around.  If a scanline of fax image data doesn't 
take at least the minimum time then things go badly.  So what we do is 
pad the end of the scanline with zeros until we transmit enough bytes 
at our current speed to meet the time minimum.

> Or is it an "imaging rate" indicator, to
> signal to
> the other side that there's no point in blasting fax data faster than
> this rate?

No.  It's more than just "pointless".  It means that data will be lost 
if it gets sent too fast because the receiver can't handle it.  (I.e., 
it prints out each line as it comes due to memory limitations, etc.)

This is only meaningful for non-ECM faxes.  ECM faxing always uses 0 
ms/scanline... no matter what the time/scanline setting on the receiver 
is.

Lee.

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