[mythtv] ATSC scan, default channel number

John P Poet jppoet at gmail.com
Thu Jul 15 22:22:50 UTC 2021


On Thu, Jul 15, 2021 at 3:45 PM Klaas de Waal <klaas.de.waal at gmail.com>
wrote:

>
>
> On Wed, 14 Jul 2021 at 22:24, Klaas de Waal <klaas.de.waal at gmail.com>
> wrote:
>
>>
>>
>> On Tue, 13 Jul 2021 at 19:49, John P Poet <jppoet at gmail.com> wrote:
>>
>>> On Tue, Jul 13, 2021 at 11:36 AM Klaas de Waal <klaas.de.waal at gmail.com>
>>> wrote:
>>>
>>>>
>>>>
>>>> On Sat, 10 Jul 2021 at 17:44, John P Poet <jppoet at gmail.com> wrote:
>>>>
>>>>> On Sat, Jul 10, 2021 at 7:30 AM Klaas de Waal <klaas.de.waal at gmail.com>
>>>>> wrote:
>>>>>
>>>>>>
>>>>>>
>>>>>> On Sat, 10 Jul 2021 at 10:32, Klaas de Waal <klaas.de.waal at gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> On Fri, 9 Jul 2021 at 22:57, John P Poet <jppoet at gmail.com> wrote:
>>>>>>>
>>>>>>>> Hi Klaas,
>>>>>>>>
>>>>>>>> I am setting up a new development machine to do some work. In the
>>>>>>>> process I noticed that when scanning ATSC channels, no default channel
>>>>>>>> number is given and the user must manually choose one for every single
>>>>>>>> channel. This is when the user chooses to manually pick which channels get
>>>>>>>> inserted into the DB.
>>>>>>>>
>>>>>>>> For example, the message I am getting is:
>>>>>>>>
>>>>>>>>> You chose to manually insert channel 7_1 (KOAT-DT). Please enter a
>>>>>>>>> unique channel channel number. Default value is
>>>>>>>>>
>>>>>>>>
>>>>>>>> If I just click on OK, it just redraws the same dialog box. Instead
>>>>>>>> I have to select Edit and type in 7_1. I could have sworn this was more
>>>>>>>> automatic the last time I did this. Any chance you can have it pick a good
>>>>>>>> default?
>>>>>>>>
>>>>>>>> Hi John,
>>>>>>>
>>>>>>> This definitely should be automatic so there is something really
>>>>>>> wrong.
>>>>>>> The correct behavior is to use the received channel number without
>>>>>>> asking and when there is a conflict the suggestion channel number is with a
>>>>>>> letter added.
>>>>>>> There should also be the option in the dialog for "OK for all"  so
>>>>>>> that it is never asked again.
>>>>>>> It could be a coincidence but there are also threads in the forum
>>>>>>> about ATSC cable scanning not working at all or crashing once the scan is
>>>>>>> complete. And that is with v31. I assume you are using master.
>>>>>>> At least you still get the correct channel numbers and names, which
>>>>>>> the ATSC cable scans do not even do anymore.
>>>>>>> What makes this a puzzle is that I have not changed anything
>>>>>>> significant in the scanning code for a long time now.
>>>>>>> On the other hand, maybe people do not do channel scans that
>>>>>>> often....
>>>>>>> The scanning does work correctly with DVB-T2/C/S2 as you might have
>>>>>>> guessed.
>>>>>>> I will have a look at the code this weekend and possibly try to do a
>>>>>>> simple ATSC scan with a captured ATSC transport stream. Have done that in
>>>>>>> the past so I should be able to do that again....
>>>>>>> In the meantime, if you have an idea what is wrong be welcome to
>>>>>>> explore and fix it!
>>>>>>>
>>>>>>> Hi John,
>>>>>>
>>>>>> Can you please send me a complete backup of your database after you
>>>>>> have done one or more scans?
>>>>>> Rationale:
>>>>>> In master the "Scan type"  "Import Existing Scan" allows playing back
>>>>>> again a scan previously done. I expect the bug to be in the channel
>>>>>> importer where the options such as "Complete scan data required" etc are
>>>>>> processed and this can be replayed from an existing scan. Which then
>>>>>> hopefully enables me to debug the channel numbering code with your ATSC
>>>>>> scan.
>>>>>>
>>>>>> Thanks,
>>>>>> Klaas.
>>>>>>
>>>>>
>>>>> Yes, I can do that. I will replicate what I did when I saw the
>>>>> problem, which was to do a scan on an initial setup, i.e. brand new
>>>>> database.
>>>>>
>>>>>
>>>>> Hi John,
>>>>
>>>> I've resurrected the capability to scan from a single transport stream,
>>>> according to your description in
>>>>
>>>> https://github.com/MythTV/mythtv/commit/8828cc5e4698f72e25fcfc31782c42fda5079717#diff-09ba904030e3795f57e6332cba578167
>>>> "Add the ability to scan for the programs in a MPTS stream from an IPTV
>>>> source."
>>>> I needed a small fix in channelscan_sm.cpp to make this work but that
>>>> is another story.
>>>> The good news is that I should now be able to reproduce and debug the
>>>> channel importer issue.
>>>>
>>>> Question: can you send me a full MPTS that does not scan correctly?
>>>>
>>>> Thanks,
>>>> Klaas.
>>>>
>>>
>>> Hi Klaas,
>>>
>>> Yes, I can do that. It may take me a couple of days, but I will get it
>>> to you by the end of this week.
>>>
>>>
>>> Hi John,
>>
>> It looks like I can reproduce the problem. I found a transport stream
>> from the beginning of 2020 which I think I actually got from you.
>> When I scan this with the IPTV UDP method I do get wrong results.
>> It has e.g.  KWBQ-TV which then gets channel number 5001-3, the 5001
>> being the UDP port number.
>> However, in the scan log it looks like KWBQ-TV should be 19-1 and the
>> other channels 19-2, 19-3 and 19-4.
>> This is the VCT:
>> (HandleVCT) - ChannelScanSM[7]: Got a Virtual Channel Table for 0
>> (LogLines) - Terrestrial Virtual Channel Section
>> (LogLines) - PSIP tableID(0xc8) length(215) extension(0x817)
>> (LogLines) - version(0) current(1) section(0) last_section(0)
>> (LogLines) - atsc_protocol_version(0)
>> (LogLines) - channel_count(4) tsid(0x0817)
>> (LogLines) - Channel #0 name(KWBQ-TV) 19-1 mod(ATSC 8-VSB) cTSID(0x0817)
>> (LogLines) - pnum(3) ETM_loc(1) access_ctrl(0) hidden(0) hide_guide(0)
>> service_type(ATSC TV)
>> (LogLines) - source_id(1)
>> (LogLines) - descriptors length(23) count:1
>> (LogLines) - Service Location Descriptor tag(0xa1) length(21) Dumping
>> (LogLines) - 000 e0 31 03 02 e0 31 00 00 00 81 e0 34 65 6e 67 81 |.1...1
>> .....4eng.|
>> (LogLines) - 010 e0 35 73 70 61 |.5spa|
>> (LogLines) - Channel #1 name(Grit) 19-2 mod(ATSC 8-VSB) cTSID(0x0817)
>> (LogLines) - pnum(4) ETM_loc(1) access_ctrl(0) hidden(0) hide_guide(0)
>> service_type(ATSC TV)
>> (LogLines) - source_id(2)
>> (LogLines) - descriptors length(17) count:1
>> (LogLines) - Service Location Descriptor tag(0xa1) length(15) Dumping
>> (LogLines) - 000 e0 41 02 02 e0 41 00 00 00 81 e0 44 65 6e 67
>> |.A...A.....Deng|
>> (LogLines) - Channel #2 name(Laff) 19-3 mod(ATSC 8-VSB) cTSID(0x0817)
>> (LogLines) - pnum(5) ETM_loc(1) access_ctrl(0) hidden(0) hide_guide(0)
>> service_type(ATSC TV)
>> (LogLines) - source_id(3)
>> (LogLines) - descriptors length(17) count:1
>> (LogLines) - Service Location Descriptor tag(0xa1) length(15) Dumping
>> (LogLines) - 000 e0 51 02 02 e0 51 00 00 00 81 e0 54 65 6e 67
>> |.Q...Q.....Teng|
>> (LogLines) - Channel #3 name(Ion) 19-4 mod(ATSC 8-VSB) cTSID(0x0817)
>> (LogLines) - pnum(6) ETM_loc(0) access_ctrl(0) hidden(0) hide_guide(0)
>> service_type(ATSC TV)
>> (LogLines) - source_id(4)
>> (LogLines) - descriptors length(17) count:1
>> (LogLines) - Service Location Descriptor tag(0xa1) length(15) Dumping
>> (LogLines) - 000 e0 61 02 02 e0 61 00 00 00 81 e0 64 65 6e 67
>> |.a...a.....deng|
>>
>> I think that this is the problem so I will start looking into this.
>>
>> The channel numbers like 5001-3 are generated because they are scanned as
> IPTV channels.
> This is done in channelscan_sm.cpp lines 1712-1714.
> When I select a manual install then the channel numbers lik 5001-3 are
> suggested as default. Pressing OK accepts this. Which is correct.
> It would be possible to use ATSC major-minor as default channel number
> also for IPTV channels but that is then new functionality, not a bug fix.
> I have not yet been able to find the path in the code that generates an
> empty default channel number when using the manual install.
> It would be nice to have an "OK all" option when manual install is
> selected, to accept the default for all following channels.
> Question: do you use IPTV or HDHomeRun or /dev/dvb tuners?
>
> To be continued!
> Klaas.
>

Hi Klass,

My scan was done using a DVB tuner.
Sorry, I have not gotten you the DB/logs you asked for. I still hope to get
that done this week.

Thanks,

John
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