[mythtv-users] DVB Scanning: single transport only

[Terjesen Jens Peder]

Tom Hill wrote:

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Hi,

I'm currently trying to scan a very specific set of DVB-S transports
from Astra-28; just the transports responsible for providing Freesat
(UK) channels -- which are almost all on 2D.

My problem is that, from what I can gather, the NIT data provides
transponder information that then triggers a scan of many other
transports, most of which are missing any form of free-to-air channels
(Sky channels, mostly) or are in foreign languages that I don't speak,
or are just plan junk channels (dating, porn, etc.)

This wouldn't be a problem, if the ratio of what I would like, to what I
receive, wasn't huge... But there's a lot of junk returned into the
channel list and, from my position, it would be a lot easier to simply
provide a list of the transports (transponders) that I want to scan and
be done with it.

I have previously been able to manually input details for 8-10
transponders with tvheadend and return only the specific channels
required, which was brilliant (however the software isn't quite ready
for general use, IMO) so I do know that the DVB-S card I have *can* do
this, but so far it seems like this ability is completely missing from
Myth.

When providing the transponder data to Myth with 'Full Scan (Tuned)' the
scanner only uses this for obtaining NIT data and then simply does its
own thing[0] by scanning everything - not useful for me at all, given
most channels are useless.

(Note that the 'ignore encrypted channels' is not the option I need.)

Furthermore, I have also observed the same behaviour with the 'scan'
utility. Using a modified version of
the /usr/share/dvb/dvb-s/Astra-28.2E file (removing those transports
that I do not require) I notice that it too utilises the NIT data,
scanning the requested transports first and then proceeding to scan all
other transports, without being asked.

There does not appear to be an option to disable the use of NIT data
when scanning with 'scan' or with MythTV, so I'm currently facing a very
frustrating operation to trim an enormous channels.conf, do to ~20 or so
channels that I actually need.

My first query is: is it possible to have Myth ignore the NIT data,
instead doing what is specifically asked? Purely within the options
available in the backend setup?

If the answer is no, would any dev wish to comment on whether scanning a
single transponder, ignoring NIT data, could be added as a scanning
option?

Lastly; perhaps I am missing something from the help output of scan, but
can this utility be coerced into providing a useful channels.conf? Maybe
if I run it with some combination of options or with a particular
keyword in the initial configuration?

Many thanks to all in advance, for any input they may have. :)

Regards,

Tom


[0] Supposedly appropriate behaviour:
http://code.mythtv.org/trac/ticket/6941

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This procedure should work.

Do a 'Full Scan (Tuned)' to get all the transponders into the database.
Delete all channels.
Do a scan on individual transponders for the channels you are interested in.

Jens