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

[John Pilkington]

On 12/10/15 13:23, Stuart Auchterlonie wrote:
> On 03/10/15 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.
>>
>
> Just so I understand this properly. The multiplexes which are actually
> DVB-T2 muxes, were put into the database as DVB-T multiplexes?
>
> How far off were the frequencies from what is correct?
> Was it listing an offset frequency rather than the centre frequency?
>
>
> Regards
> Stuart

Sorry, Stuart, I'm afraid I didn't take detailed notes and that box 
isn't fired up at present - although it now works well.  My note was 
intended to suggest things to look out for in case of problems.  It's 
been my experience that these happen after a retune, and often seem 
unrepeatable, but can usually be worked around.  I didn't need to poke 
the DB.

AFAIR, after the first 'all known and linked transports' scan the DVB-T2 
slot was blank in the transport editor while the others showed as DVB-T. 
  A new, low-power, third DVB-T2 mux wasn't seen, but was picked up by 
the full scan.

According to ukfree.tv my transmitter, Waltham, has only one offset mux. 
After the full-scan-ab-initio I think that that one may have been 
detected, and another spurious one was too.  I know that when I first 
tried DVB-T2, almost 4 years ago, a spurious offset was reported (by 
vlc) - gossamer-threads.../users/499148#499148

Apologies, again, for the vagueness.

John