[linux-dvb] au tuning files

Christoph Pfister christophpfister at gmail.com
Tue Jun 5 18:56:22 CEST 2007


Am Sonntag, 3. Juni 2007 10:56 schrieb Peter D.:
> Hi,
> I'm taking some things on trust here, so feel free to tell me I am wrong.
> My main source is http://www.dba.org.au/index.asp?sectionID=120
> It says, among other things;
> 	these parameters may be changed from time to time without warning,
> 	receivers need to comply with Standards Australia standards AS 4933
> 	and AS 4599, as well as DVB standards, that say a receiver needs to
> 	identify and receive all COFDM modes, including hierarchical (see
> 	below), and
> 	the receiver should check the Transmission Parameter Signaling (TPS)
> 	some broadcasters use centre frequency offsets
> I'm not sure how clever that means tuners sold in Australia should be or,
> more importantly, actually are.
> In this post
> http://www.linuxtv.org/pipermail/linux-dvb/2007-May/018262.html John
> offered a tuning file for Australia that was mostly full of "AUTO"s with
> what looks like an entry for every frequency used in Australia.  It works
> for me with a Kworld/VStream Xpert card in Melbourne.
> I don't know how much the Australian "standards" vary from international
> standards, but I believe that one or two channels have been moved by a
> Mega Hertz and an extra channel (9A) added.  Channel 12 might be non
> standard
> too, I don't know.
> Looking through the au-* tuning files and the www.dba.org.au site there are
> some things that are still a mystery to me.
> There seem to be many more transmitters scattered around the country than
> are mentioned in the au-* tuning files.

There are two possible reasons for this:
- People submitted stuff for regions where they live, so certain areas aren't 
covered at all.
- Single-frequency network; multiple transmitters use the same frequency (and 
also the same modulation parameters), so you don't need a scan file for each 
of them.

> The www.dba.org.au site only lists a single FEC for each group of channels,
> while the tuning files have a fec_hi and a fec_lo.  In many files that is
> given as a fraction and a "NONE", sometimes as two fractions, usually the
> same fraction - sometimes as different ones.
> Is the fec_low value used?  Only valid sometimes?  Should it be "AUTO",
> "NONE", the same as fec_hi, or is it an independent variable?

If no hierarchy is involved, it doesn't matter. Ideally it should be set to 
NONE in that case, but this doesn't happen very often.

> The big problem is that *most* of the channel 7 transmitters have changed
> their guard interval.
> The changes that I am offering here seem to be improvements, but I can
> only test Melbourne stuff.
> au-Perth and au-Melbourne have recently changed to have the new ch7 GI.
> The files attached are;
> A generic Australian file, au-auto, from John.
> au-Adelaide,		new ch7 GI
> au-Cairns,		new ch7 GI
> au-Canberra-Black-Mt,	new Prime FEC and GI
> au-Darwin,		new Southern Cross FEC and GI, new ch9 FEC and GI
> au-Melbourne-Upway,	new ch7 GI
> au-MidNorthCoast,	lots of changes
> au-SpencerGulf,		new SBS FEC
> au-Sydney_Kings_Cross,	new ch7 GI
> au-Townsville,		new ch7 GI
> There are other au-*tuning files that I am not offering changes for.

Thanks for your effort! I'll deal with them soon - maybe there's also the 
possibility to create those files by a script so updates can be done more 
easily ...


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