[mythtv-users] MtrhTv: Uk Mendip Transmitter issues

Terry Barnaby terry1 at beam.ltd.uk
Wed Jul 14 17:23:19 UTC 2010


On 13/07/10 09:43, John Pilkington wrote:
>
>>
>> Ok, I have finally found the problem. The transportid for the Virgin1
>> Multiplex was incorrect in the dtv_multiplex database table. There is no
>> way of editing this using mythtvsetup, but it has to be correct.
>> I guess I did a full scan and then edited some of the incorrect
>> multiplexes (neighbouring transmitters) to to right values for
>> the local transmitter. Unfortunately the transportid was not changed.
>> I consider this a bug in either mythtvsetup by not allowing it
>> to be edited or in the mythtv SDT parser as it could find out the
>> correct transportid for the stream it is decoding.
>> I'm not sure how you would find the correct transportid value except
>> by using dvbsnoop...
>>
>> Cheers
>>
>>
>> Terry
>
> Good to know you've identified the problem: have you got it working now,
> and if so how? Did a scan of some sort within MythTV do the job or have
> you _needed_ other tools?
>
> John P
>
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Yes, its all fully working now.

Basically I downloaded and built dvbsnoop to look at the packets
from the multiplex when tuned in with tzap.
So I ran "tzap -r -c channels.conf "Virgin1".
In a separate window I ran "dvbsnoop -s pidscan".
Then I ran "dvbsnoop -n 1 -nph 0x0103" where 0x0103 was the pid
of the SDT.
I had to run this a number of times as multiple SDT's are sent
for neighbouring multiplexes until the one for this multiplex
is sent (listed as such, can't quite remember the wording).
Within the SDT is the transportid.
I then edited the Mysql database using "mysql" to set the
correct transportid in the dvb_multiplex for the multiplex
in question.

There is probably a better way of finding the transportid, also
mythtv must determine and set this automatically from a full
channel scan, so maybe it can determine this automatically
some how (set transportid to 0/null ?? ) ??

Cheers


Terry


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