[mythtv] ATSC scan, default channel number

Wed Jul 14 20:24:19 UTC 2021

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.
To be continued!

Groetjes,
Klaas.
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