[mythtv-users] BBC HD sat mux transport parameter change...

Robert Longbottom rongblor at googlemail.com
Wed Sep 5 21:50:15 UTC 2012

On 05/09/2012 22:28, Andy Sheen wrote:
> Hi all,
> Any one with any clues about this. It must be an easy answer for those
> in the know (at least for what I can do by messing in the database).
> Thanks
> Andy
> On 4 September 2012 23:26, Andy Sheen <sheen.andy at googlemail.com
> <mailto:sheen.andy at googlemail.com>> wrote:
>     Hi all,
>     So Auntie Beeb are going to be playing with their parameters for the BBC
>     HD/BBC One HD stream on the 27th September.
>     According to: http://www.bbc.co.uk/blogs/aboutthebbc/2012/09/blah.shtml
>     They will be changing the transponder from:
>     10,847MHz, Vertical, DVB-S2, QPSK, 23M, 8/9 FEC
>     to:
>     10,847MHz, Vertical, DVB-S2, 8PSK, 23M, 2/3 FEC
>     Given the ONLY changes are QPSK -> 8PSK and 8/9 -> 2/3 FEC, this seems
>     like a change I'm willing to do via playing with the database directly
>     (backup/yes, I know I could kill the system, here might be dragons, we
>     don't recommend it all noted ;)). So... FEC 8/9 -> 2/3 is easy enough to
>     do, but what do I do about the modulation field in dtv_multiplex? Change
>     qpsk to 8psk, leave it as qpsk, or something else?
>     Also, I assume that my cards/drivers/MythTV have support for 8PSK in
>     them - googling would lead me to believe they are supported. I'm running
>     a Tevii S480 and Hauppauge WinTV-HVR400 under Ubuntu 12.04LTS with
>     mythbackend version: fixes/0.25 [v0.25.1-49-g65913e7].
>     Is there any way to check this before the date? Should I just relax? I'm
>     paranoid about this as I work with embedded sat systems and I know
>     making assumptions about what tuners do and don't support in their
>     drivers is dangerous....
>     Thanks
>     Andy

I'll start by saying that I have BBC HD and BBC One HD working on my system.

Have you looked at what settings are actually in your database?

I've just looked in mine and currently the only "constellation" values I 
have are NULL and qpsk:

mysql> select distinct constellation from dtv_multiplex;
| constellation |
| NULL          |
| qpsk          |

And for the BBC [One] HD frequency:

mysql> select * from dtv_multiplex where frequency = 10847000\G
*************************** 1. row ***************************
           mplexid: 39
          sourceid: 1
       transportid: 2050
         networkid: 2
         frequency: 10847000
         inversion: a
        symbolrate: 23000000
               fec: 8/9
          polarity: v
        modulation: qpsk
         bandwidth: NULL
      lp_code_rate: NULL
transmission_mode: NULL
    guard_interval: NULL
           visible: 0
     constellation: NULL
         hierarchy: NULL
      hp_code_rate: NULL
           mod_sys: DVB-S2
           rolloff: NULL
        sistandard: dvb
    serviceversion: 0
   updatetimestamp: 2011-06-06 17:43:58
1 row in set (0.00 sec)

So it looks like I might need to change fec, which as you say is easy. 
As for constellation, it's NULL anyway, which I'm guessing means auto?


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