[mythtv] what are the right frequency offsets?

R. G. Newbury newbury at mandamus.org
Mon Apr 5 02:03:16 UTC 2010


On 04/04/2010 10:37 AM, Petr Stehlik wrote:
> Hi,
>
> 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). 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.
>
> 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.


Wikipedia states that there are minor differences in the PAL standard 
which Western Europe uses. France uses the SECAM standard which might 
explain one difference, although why the French offsets work at seems 
odd to me. This page:
http://en.wikipedia.org/wiki/Television_channel_frequencies

seems to be a fairly exhaustive list of channel v. frequency for 
broadcast usage (probably extracted from ITU documentation).

No idea if this matches the internal tables at all...
Geoff




-- 
         Please let me know if anything I say offends you.
          I may wish to offend you again in the future.

          Tux says: "Be regular. Eat cron flakes."


More information about the mythtv-dev mailing list