[mythtv-users] Help understanding DVB-T settings

[Neil Bird]

   I finally believe I've got my Nova-T DVB set-up reliable†, and in setting 
up some dummy recordings overnight to prove it I realised one of the 
stations wasn't working.  It fails to record, and LiveTV gives up with an 
error & returns to the menu:  just for this one channel.

   I assumed it was just that the channel had relocated in the months since 
I'd set it up, but a scandvb reveals the same data for this channel as in my 
old channels.conf, and a tzap of the channel gets a lock.

   So, I'm thinking now that the channel data in Myth's SQL doesn't match 
the channel.con (although I've fairly certain I set it up originally from a 
channel.conf-import in mythtv-setup).

   The values look OK to my limited knowledge of DVB;  can anyone who knows 
a bit more cast an eye over them, please?  [below]

   I'll try over the W/E after I've upt in 0.20 which has the new extended 
wait for lock setting.


   On a related note, what's the current scheme for DVB maintenance?  I 
understand that for a brief period Myth would scan automatically for new 
channels and add them, but that had issues and was removed.  I do recall 
spending an inordinate amount of time deleting unwanted channels from my 
channels.conf import, then setting up all the xmltvids, and I'm concerned 
that if I do a re-scan via Myth, all my current [DVB card] channel settings 
will be blatted.

   Can anyone enlighten me?


   Here are what I believe to be the relevant settings for this problem 
channel: [apologies if the wide table goes screwy]


UKTV Gold

mysql> select chanid,channum,name,mplexid,serviceid from channel where name 
= 'uktv gold';
+--------+---------+-----------+---------+-----------+
| chanid | channum | name      | mplexid | serviceid |
+--------+---------+-----------+---------+-----------+
|    109 | 109     | UKTV Gold |    NULL |      NULL |  <- satellite version
|   3539 | 17      | UKTV Gold |       5 |     15552 |  <- DVB version
+--------+---------+-----------+---------+-----------+
2 rows in set (0.00 sec)

mysql> select * from dtv_multiplex where mplexid=5;
+---------+----------+-------------+-----------+-----------+-----------+------------+------+----------+------------+-----------+--------------+-------------------+----------------+---------+---------------+-----------+--------------+------------+----------------+---------------------+
| mplexid | sourceid | transportid | networkid | frequency | inversion | 
symbolrate | fec  | polarity | modulation | bandwidth | lp_code_rate | 
transmission_mode | guard_interval | visible | constellation | hierarchy | 
hp_code_rate | sistandard | serviceversion | updatetimestamp     |
+---------+----------+-------------+-----------+-----------+-----------+------------+------+----------+------------+-----------+--------------+-------------------+----------------+---------+---------------+-----------+--------------+------------+----------------+---------------------+
|       5 |        3 |        NULL |      NULL | 522000000 | a         | 
       0 | auto | v        | auto       | 8         | 1/2          | 2 
            | 1/32           |       0 | qam_64        | n         | 2/3 
       | dvb        |             33 | 2006-02-26 19:31:56 |
+---------+----------+-------------+-----------+-----------+-----------+------------+------+----------+------------+-----------+--------------+-------------------+----------------+---------+---------------+-----------+--------------+------------+----------------+---------------------+
1 row in set (0.00 sec)


channels.conf entry:
UKTV 
Gold:522000000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_2_3:FEC_1_2:QAM_64:TRANSMISSION_MODE_2K:GUARD_INTERVAL_1_32:HIERARCHY_NONE:6497:6498:15552



† - gah, the reason my DVB's been unreliable since I set it up months ago is 
because I followed my DVB TV's recommendation and fed the UHF TV cable from 
it's *out* into my DVD recorder and thence Myth, essentially leaving my 
existing wiring untouched (aerial -> videos -> TV).  Except when I turn the 
TV off it's UHF feed-through stops, so neither my DVB DVD recorder nor Myth 
could see anything :-/  Which also explains the really odd situation I had 
where recordings would mostly fail but LiveTV always worked.  D'oh!

-- 
[neil at fnx ~]# rm -f .signature
[neil at fnx ~]# ls -l .signature
ls: .signature: No such file or directory
[neil at fnx ~]# exit