[mythtv] [mythtv-commits] Ticket #12342: Add support for DVB-T2 for tuners that do not auto-switch

David Matthews dm at prolingua.co.uk
Tue Oct 13 13:34:45 UTC 2015

On 03/10/2015 15:12, John Pilkington wrote:
> On 30/09/15 17:45, MythTV wrote:
>> #12342: Add support for DVB-T2 for tuners that do not auto-switch
>> -----------------------------------+-----------------------------
>>   Reporter:  David Matthews <dm@…>  |          Owner:  stuarta
>>       Type:  Patch - Feature        |         Status:  assigned
>>   Priority:  minor                  |      Milestone:  0.28
>> Component:  MythTV - DVB           |        Version:  Master Head
>>   Severity:  medium                 |     Resolution:
>>   Keywords:                         |  Ticket locked:  0
>> -----------------------------------+-----------------------------
>> Comment (by David Matthews <dm@…>):
>>   In [changeset:"02f2d5e7abd522eb5195548513b58a5f7bb6c209/mythtv"]:
>>   {{{
>>   #!CommitTicketReference repository="mythtv"
>>   revision="02f2d5e7abd522eb5195548513b58a5f7bb6c209"
>>   Support for DVB-T2 in the channel scanner.  When used with a card that
>>   supports DVB-T2
>>   it adds the ability to select DVB-T/T2 when editing a transport and
>>   extends the full
>>   scan to check whether a frequency will lock with DVB-T2.  It only tests
>>   for DVB-T2 if it
>>   has failed to lock with DVB-T to avoid having duplicate entries with
>> cards
>>   that auto-switch
>>   between DVB-T and DVB-T2.  It also fixes a bug where previously if a
>> lock
>>   was obtained
>>   with an offset frequency but not with the centre frequency the entry in
>>   the database
>>   contained only the centre frequency.
>>   (cherry picked from commit 2bfbbf39cc5819bd8767baa1586d98e53abd15a2)
>>   Signed-off-by: Stuart Auchterlonie <stuarta at squashedfrog.net>
>>   Conflicts:
>>           mythtv/libs/libmythtv/cardutil.h
>>           mythtv/libs/libmythtv/channelscan/channelscan_sm.cpp
>>   Refs #12342
>>   }}}
>> --
>> Ticket URL: <https://code.mythtv.org/trac/ticket/12342#comment:9>
> I have a PCTV-290e, which has used an auto-switching driver but TTBOMK
> is no longer marketed.  I wanted to see if this commit would affect it.
> After installing the *buntu ppa build I deleted and re-enabled the 290e
> 'capture card' and rescanned for channels using my usual 'all known
> transports+' option.  The scan went fine, but T2 channels did not record
> until I had manually inserted the T2 option via the transport editor.
> I then deleted all transports and did a full scan.  Recordings worked,
> but all the qam-type entries were left as AUTO and the frequency offsets
> reported were not all as expected.  In the hope of getting greater
> robustness I have edited-in the 'correct' values.
> I get usable signals from only one transmitter, and the laptop used has
> no other capture device.

Before I submitted the patch I checked it with my PCTV-490e in case 
there were problems.  I've now gone back and checked that the current 
master works with the PCTV-490e and it was fine.  All the multiplexes 
were found and I was able to tune at least one channel on each multiplex.

All the frequencies were centre frequencies even though one multiplex 
has an offset.  The other entries in the dtv_multiplex table were AUTO, 
which I would expect.  Most of the entries were "DVB-T" even if they 
were actually T2 multiplexes.  Again that's what I'd expect.  One, 
though, actually a DVB-T multiplex, appeared as "DVB-T2".  That didn't 
affect the tuning, the driver seems to ignore the T/T2 mode, and might 
have happened because the device didn't manage to lock the first time 
when it tried with DVB-T and only gained a lock at the second attempt 
with DVB-T2.


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