[mythtv] what are the right frequency offsets?

[Janne Grunau]

On Sun, Apr 04, 2010 at 04:37:09PM +0200, Petr Stehlik wrote:
> 
> in libs/libmythtv/frequencytables.cpp's init_freq_tables() there's a
> list of tables for various countries. I have submitted a Czech DVB-T
> table that works great for some tuners (much better than Germany or
> France tables that we used to use before) but is worse for certain other
> tuners (ASUS My Cinema-P7131 Hybrid).

Yeah, I guess some tuners search enough spectrum to find the pilots also
on the offsetted frequencies. It also depends on the transmitter.

> After some trial&error it turned
> out that by using the French offsets (the last two parameters, -166000
> and 167000) the channel scanning works better.
> 
> Thus I am wondering how I can find out the correct offsets for DVB-T.
> I've seen it set to 0,0 for most countries but some have 125000 and
> other have the -166k/167k.

http://forum.team-mediaportal.com/submit-epg-grabbers-tuningdetails-296/dvb-t-updated-tuning-parameters-czech-republic-ostrava-74844/
uses 12.5k as offsets.

> Thanks for any pointer. I'd  like to get it fixed in time for 0.23 but
> before submitting a patch with the French offsets for the Czech table
> I'd like to know if it's possible to compute the parameters somehow
> instead of guessing them.

This are official transmitter parameters and should be published
somewhere. I couldn't find anything in english.

HTH

Janne