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MtrhTv: Uk Mendip Transmitter issues

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terry1 at beam

Jul 4, 2010, 10:29 AM

Post #1 of 15 (1198 views)
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MtrhTv: Uk Mendip Transmitter issues

Hi,

I have been having quite a problem to get MythTv to work well after
the Multiplex changes on the Mendip transmitter in April.
Apart from issues where neighbouring transmitter multiplexes
that are are found (from info from the Mendip transmitters
info lists) and added to the list, which I have got around,
the main issue is that I don't seem to be able to tune to
channels from the "A" Multiplex.

I have been playing around with dvbscan to check things out and
to make sure by signal levels etc are about right. However
I see a strange issue. If I give dvbscan the main "PSB1"
multiplex to start with if finds the other multiplexes but
gets some of the parameters wrong.

The correct settings I believe are:
T 794000000 8MHz 2/3 NONE QAM64 8k 1/32 NONE # PSB1
T 738000000 8MHz 2/3 NONE QAM64 8k 1/32 NONE # PSB2
T 802167000 8MHz 2/3 NONE QAM64 2k 1/32 NONE # A
T 754167000 8MHz 3/4 NONE QAM16 2k 1/32 NONE # C
T 778167000 8MHz 3/4 NONE QAM16 2k 1/32 NONE # D

These work when you manualy set them for dvbscan.

However if dvbscan scans from the main multiplex it returns:
initial transponder 794000000 0 2 9 3 1 0 0
>>> tune to:
794000000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_2_3:FEC_AUTO:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_32:HIERARCHY_NONE
>>> tune to:
738000000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_2_3:FEC_1_2:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_32:HIERARCHY_NONE
>>> tune to:
802167000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_2_3:FEC_1_2:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_32:HIERARCHY_NONE
WARNING: >>> tuning failed!!!
>>> tune to:
754167000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_2_3:FEC_1_2:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_32:HIERARCHY_NONE
WARNING: >>> tuning failed!!!
>>> tune to:
778167000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_2_3:FEC_1_2:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_32:HIERARCHY_NONE
WARNING: >>> tuning failed!!!

It has got the settings wrong in the last three multiplexes.

Is this a bug in dvbscan or is the transmitter sending out the wrong info ??

If I create channels.conf by manually adding the channels from each multiplex
in turn (setting the parameters correctly) I can tune into the channels
with tzap ok. If I use tzap to tune in "Virgin1" which is in multiplex A
I get a lock, a reasonable signal level, a reasonable SignalToNoise ratio, and a
low bit error rate between 0 and 8.

If I use these Multiplex values and enter them into Mythtv as its transponders
and re-scan for channels, all works fine and I get all of the channels listed.
However if I try and tune to "Virgin1" I get no-lock.

My feeling is that MythTv is also getting the DVB parameters wrong.
Is there a way I can get MythTv (frontend or backend) to list the DVB
parameters it is using ?

Cheers

Terry

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J.Pilk at tesco

Jul 4, 2010, 11:40 AM

Post #2 of 15 (1163 views)
Permalink

Re: MtrhTv: Uk Mendip Transmitter issues [In reply to]

On 04/07/10 18:29, Terry Barnaby wrote:
> Hi,
>
> I have been having quite a problem to get MythTv to work well after
> the Multiplex changes on the Mendip transmitter in April.
> Apart from issues where neighbouring transmitter multiplexes
> that are are found (from info from the Mendip transmitters
> info lists) and added to the list, which I have got around,
> the main issue is that I don't seem to be able to tune to
> channels from the "A" Multiplex.
>
> I have been playing around with dvbscan to check things out and
> to make sure by signal levels etc are about right. However
> I see a strange issue. If I give dvbscan the main "PSB1"
> multiplex to start with if finds the other multiplexes but
> gets some of the parameters wrong.
>
> The correct settings I believe are:
> T 794000000 8MHz 2/3 NONE QAM64 8k 1/32 NONE # PSB1
> T 738000000 8MHz 2/3 NONE QAM64 8k 1/32 NONE # PSB2
> T 802167000 8MHz 2/3 NONE QAM64 2k 1/32 NONE # A
> T 754167000 8MHz 3/4 NONE QAM16 2k 1/32 NONE # C
> T 778167000 8MHz 3/4 NONE QAM16 2k 1/32 NONE # D
>
> These work when you manualy set them for dvbscan.
>
> However if dvbscan scans from the main multiplex it returns:
> initial transponder 794000000 0 2 9 3 1 0 0
>>>> tune to:
> 794000000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_2_3:FEC_AUTO:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_32:HIERARCHY_NONE
>
>>>> tune to:
> 738000000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_2_3:FEC_1_2:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_32:HIERARCHY_NONE
>
>>>> tune to:
> 802167000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_2_3:FEC_1_2:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_32:HIERARCHY_NONE
>
> WARNING: >>> tuning failed!!!
>>>> tune to:
> 754167000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_2_3:FEC_1_2:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_32:HIERARCHY_NONE
>
> WARNING: >>> tuning failed!!!
>>>> tune to:
> 778167000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_2_3:FEC_1_2:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_32:HIERARCHY_NONE
>
> WARNING: >>> tuning failed!!!
>
> It has got the settings wrong in the last three multiplexes.
>
> Is this a bug in dvbscan or is the transmitter sending out the wrong
> info ??
>
> If I create channels.conf by manually adding the channels from each
> multiplex
> in turn (setting the parameters correctly) I can tune into the channels
> with tzap ok. If I use tzap to tune in "Virgin1" which is in multiplex A
> I get a lock, a reasonable signal level, a reasonable SignalToNoise
> ratio, and a low bit error rate between 0 and 8.
>
> If I use these Multiplex values and enter them into Mythtv as its
> transponders and re-scan for channels, all works fine and I get all of
> the channels listed.
> However if I try and tune to "Virgin1" I get no-lock.
>
> My feeling is that MythTv is also getting the DVB parameters wrong.
> Is there a way I can get MythTv (frontend or backend) to list the DVB
> parameters it is using ?
>
> Cheers
>
>
> Terry
>
Hi again (from the4 dev list): Have you looked at the 'Edit Transports'
page in the Channel Editor section of mythtvsetup? Mine shows 'QAM
Auto', coderates Auto, but if you're dissatisfied you can select
specific values; don't know if it works but maybe worth a shot.

There might also be a hardware link. I have Freecom dvb-t stick from
about 2006 that used to work but then failed to tune the BBC Four mux, I
think because it can't pass the full transport stream to the demuxers.
The hardware wiki - and maybe dmesg - might show if that was likely to
be a problem for you.

John P

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mikep at randomtraveller

Jul 4, 2010, 12:21 PM

Post #3 of 15 (1158 views)
Permalink

Re: MtrhTv: Uk Mendip Transmitter issues [In reply to]

Terry Barnaby wrote:
>
> I have been playing around with dvbscan to check things out and
> to make sure by signal levels etc are about right. However
> I see a strange issue. If I give dvbscan the main "PSB1"
> multiplex to start with if finds the other multiplexes but
> gets some of the parameters wrong.
>
> The correct settings I believe are:
> T 794000000 8MHz 2/3 NONE QAM64 8k 1/32 NONE # PSB1
> T 738000000 8MHz 2/3 NONE QAM64 8k 1/32 NONE # PSB2
> T 802167000 8MHz 2/3 NONE QAM64 2k 1/32 NONE # A
> T 754167000 8MHz 3/4 NONE QAM16 2k 1/32 NONE # C
> T 778167000 8MHz 3/4 NONE QAM16 2k 1/32 NONE # D
>
What happened to the /sixth/ multiplex? Is this the one 'they' have withdrawn in
order to set up for HD?

--

Mike Perkins

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malcolm.torrent at gmail

Jul 4, 2010, 2:04 PM

Post #4 of 15 (1159 views)
Permalink

Re: MtrhTv: Uk Mendip Transmitter issues [In reply to]

terry1 at beam

Jul 4, 2010, 2:42 PM

Post #5 of 15 (1154 views)
Permalink

Re: MtrhTv: Uk Mendip Transmitter issues [In reply to]

On 04/07/10 22:04, malcolm wrote:
> On 04/07/10 18:29, Terry Barnaby wrote:
>> Hi,
>>
>> I have been having quite a problem to get MythTv to work well after
>> the Multiplex changes on the Mendip transmitter in April.
>> Apart from issues where neighbouring transmitter multiplexes
>> that are are found (from info from the Mendip transmitters
>> info lists) and added to the list, which I have got around,
>> the main issue is that I don't seem to be able to tune to
>> channels from the "A" Multiplex.
>>
>>
> I live in the Mendip region and also find that I receive additional
> channels from Wenvoe (in Wales). Using the internal mythtv scan /
> channel search I do get multiple results from additional Wenvoe muxs.
> However, I filter these out after allocation of the channel number using
> Mythweb.
>
> Post the commands you used and I'll see what results I get.
> _______________________________________________
> mythtv-users mailing list
> mythtv-users [at] mythtv
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
John, Yes I have used the Edit Transports to set up the transports.
They were all set to Auto on most of the settings, But I have
been setting them to try and get Multiplex A (Virgin1 etc).

I have two DVB-T tuners, a PCI Twinhan one and a Haupuage NovaT
USB one. Both appear to have the same issue. These worked before
April fine.

Mike, Yes the 6th Multiplex is HD, can't obviously use that yet :(
I have a DVB-S2 card for HD.

I got rid off the extra Wenvoe channels by editing the Transponders
and doing a scan with the existing Transponders only. This appears
to have worked fine, all the expected channels are listed. I just
don't seem to be able to tune into any of the channels on
the A Multiplex. I have set parameters to Auto and then to those
listed at: http://www.ukfree.tv/txdetail.php?a=ST564488. Both
schemes have not worked (plus many other tries).

So I tried with scandvb. For my testing with scandvb I had a
uk-Mendip file with the following:
T 794000000 8MHz 2/3 NONE QAM64 8k 1/32 NONE # PSB1
#T 738000000 8MHz 2/3 NONE QAM64 8k 1/32 NONE # PSB2
#T 802167000 8MHz 2/3 NONE QAM64 2k 1/32 NONE # A
#T 754167000 8MHz 3/4 NONE QAM16 2k 1/32 NONE # C
#T 778167000 8MHz 3/4 NONE QAM16 2k 1/32 NONE # D

When I ran "scandvb -a 0 uk-Mendip" it found the other Multiplex
frequencies (plus some of the Wenvoe ones) but reported incorrect
settings for the QCAM and transmission mode parameters for A,C and
D and could not tune into these to get channels.

If I have the following in my uk-Mendip file

T 802167000 8MHz 2/3 NONE QAM64 2k 1/32 NONE # A

The scandvb tunes and finds all the channels in Multiplex A.
So either there is a bug in scandvb in getting wrong Multiplex
parameters from the info broadcast from Mendip on PSB1 or the info
being broadcast is wrong. (dvb-apps-1.1.1-22.fc12.i686)

Are there any debug settings I can set on mythfrontend/mythbackend
which will print out the exact DVB settings that are being used when
it attempts to tune into a channel ? I am just wondering if
MythTv is setting the wrong parameters just as scandvb, maybe overriding
my settings with what it thinks are correct.

Cheers

Terry

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terry1 at beam

Jul 11, 2010, 3:52 AM

Post #6 of 15 (1074 views)
Permalink

Re: MtrhTv: Uk Mendip Transmitter issues [In reply to]

On 04/07/10 22:42, Terry Barnaby wrote:
> On 04/07/10 22:04, malcolm wrote:
>> On 04/07/10 18:29, Terry Barnaby wrote:
>>> Hi,
>>>
>>> I have been having quite a problem to get MythTv to work well after
>>> the Multiplex changes on the Mendip transmitter in April.
>>> Apart from issues where neighbouring transmitter multiplexes
>>> that are are found (from info from the Mendip transmitters
>>> info lists) and added to the list, which I have got around,
>>> the main issue is that I don't seem to be able to tune to
>>> channels from the "A" Multiplex.
>>>
>>>
>> I live in the Mendip region and also find that I receive additional
>> channels from Wenvoe (in Wales). Using the internal mythtv scan /
>> channel search I do get multiple results from additional Wenvoe muxs.
>> However, I filter these out after allocation of the channel number using
>> Mythweb.
>>
>> Post the commands you used and I'll see what results I get.
>> _______________________________________________
>> mythtv-users mailing list
>> mythtv-users [at] mythtv
>> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
> John, Yes I have used the Edit Transports to set up the transports.
> They were all set to Auto on most of the settings, But I have
> been setting them to try and get Multiplex A (Virgin1 etc).
>
> I have two DVB-T tuners, a PCI Twinhan one and a Haupuage NovaT
> USB one. Both appear to have the same issue. These worked before
> April fine.
>
> Mike, Yes the 6th Multiplex is HD, can't obviously use that yet :(
> I have a DVB-S2 card for HD.
>
> I got rid off the extra Wenvoe channels by editing the Transponders
> and doing a scan with the existing Transponders only. This appears
> to have worked fine, all the expected channels are listed. I just
> don't seem to be able to tune into any of the channels on
> the A Multiplex. I have set parameters to Auto and then to those
> listed at: http://www.ukfree.tv/txdetail.php?a=ST564488. Both
> schemes have not worked (plus many other tries).
>
> So I tried with scandvb. For my testing with scandvb I had a
> uk-Mendip file with the following:
> T 794000000 8MHz 2/3 NONE QAM64 8k 1/32 NONE # PSB1
> #T 738000000 8MHz 2/3 NONE QAM64 8k 1/32 NONE # PSB2
> #T 802167000 8MHz 2/3 NONE QAM64 2k 1/32 NONE # A
> #T 754167000 8MHz 3/4 NONE QAM16 2k 1/32 NONE # C
> #T 778167000 8MHz 3/4 NONE QAM16 2k 1/32 NONE # D
>
> When I ran "scandvb -a 0 uk-Mendip" it found the other Multiplex
> frequencies (plus some of the Wenvoe ones) but reported incorrect
> settings for the QCAM and transmission mode parameters for A,C and
> D and could not tune into these to get channels.
>
> If I have the following in my uk-Mendip file
>
> T 802167000 8MHz 2/3 NONE QAM64 2k 1/32 NONE # A
>
> The scandvb tunes and finds all the channels in Multiplex A.
> So either there is a bug in scandvb in getting wrong Multiplex
> parameters from the info broadcast from Mendip on PSB1 or the info
> being broadcast is wrong. (dvb-apps-1.1.1-22.fc12.i686)
>
>
> Are there any debug settings I can set on mythfrontend/mythbackend
> which will print out the exact DVB settings that are being used when
> it attempts to tune into a channel ? I am just wondering if
> MythTv is setting the wrong parameters just as scandvb, maybe overriding
> my settings with what it thinks are correct.
>
> Cheers
>
>
> Terry
>
> _______________________________________________
> mythtv-users mailing list
> mythtv-users [at] mythtv
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
Hi, I am still getting nowhere with this. I am fairly sure it is
a MythTv configuration issue or a MythTv bug. The system is working
generally fine with most channels, however the Virgin1 multiplex from
Mendip just refuses to work. It is unusual in that its mode is QCAM_64
with a 2K transmission mode.

I can tune the channel using tzap fine (dvb channel entry below).
Virgin1:802166670:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_2_3:FEC_1_2:QAM_64:TRANSMISSION_MODE_2K:GUARD_INTERVAL_1_32:HIERARCHY_NONE:6785:6786:14304

This reports very low bit errors, from 0 to a few.

When I use "mplayer - < /dev/dvb/adapter0/dvr0" the station plays fine.

However when I use MythTv I get the info "(LMs) Partial Lock" and no video and
any recordings have no file associated with them.

I have tried configuring the Multiplex manually to all possible values
to no effect. The output of "mythbackend -v channel" is attached.
I am running Fedora12 with MythTv from RpmFusion (MythTv 0.23).

Any ideas ?

Cheers

Terry

Attachments:

BugVirgin1.txt (32.6 KB)

linux at thehobsons

Jul 11, 2010, 4:27 AM

Post #7 of 15 (1075 views)
Permalink

Re: MtrhTv: Uk Mendip Transmitter issues [In reply to]

It might be worth digging back in the archives and see what
problems/solutions those of us up in Winter Hill land had last
December. From memory, I had trouble tuning stuff in (I'm still on
0.21). IIRC, I had to manually enter one mux frequency, scan that
which brought in the other transports, and then scan each of those
separately. I vaguely recall that a full scan or full rescan of
existing transports didn't work for me.

--
Simon Hobson

Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed
author Gladys Hobson. Novels - poetry - short stories - ideal as
Christmas stocking fillers. Some available as e-books.
_______________________________________________
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terry1 at beam

Jul 11, 2010, 4:42 AM

Post #8 of 15 (1070 views)
Permalink

Re: MtrhTv: Uk Mendip Transmitter issues [In reply to]

On 11/07/10 12:27, Simon Hobson wrote:
> It might be worth digging back in the archives and see what
> problems/solutions those of us up in Winter Hill land had last December.
> From memory, I had trouble tuning stuff in (I'm still on 0.21). IIRC, I
> had to manually enter one mux frequency, scan that which brought in the
> other transports, and then scan each of those separately. I vaguely
> recall that a full scan or full rescan of existing transports didn't
> work for me.
>
Thanks for the info.
Yes, I have more or less done that. I ended up:
1. Doing a full scan.
2. Editing the transports as it brought in transports from neighbouring
transmitters.
3. Deleted all channels.
4. Did a scan of the existing transports.
5. Been playing around with editing the transport values.

Generally this has worked fine. Its just the channels on this one multiplex
I am having problems with.
I will try scanning each of the transports separately, although I can't see a
reason why this should be different from scanning all of the existing ones ?

_______________________________________________
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J.Pilk at tesco

Jul 11, 2010, 4:49 AM

Post #9 of 15 (1074 views)
Permalink

Re: MtrhTv: Uk Mendip Transmitter issues [In reply to]

On 11/07/10 12:27, Simon Hobson wrote:
> It might be worth digging back in the archives and see what
> problems/solutions those of us up in Winter Hill land had last December.
> From memory, I had trouble tuning stuff in (I'm still on 0.21). IIRC, I
> had to manually enter one mux frequency, scan that which brought in the
> other transports, and then scan each of those separately. I vaguely
> recall that a full scan or full rescan of existing transports didn't
> work for me.
>
I remember that there were problems with a Virgin channel switch before:
that seems to have been in June 2009. I haven't been able to identify a
particular post, but I think there was a statement from one of the devs
- IIRC one of the Stuarts - that some of the transmitted info had been
incorrect. Looks like a long shot for your problems, though.

John P

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linux at thehobsons

Jul 11, 2010, 2:43 PM

Post #10 of 15 (1055 views)
Permalink

Re: MtrhTv: Uk Mendip Transmitter issues [In reply to]

Terry Barnaby wrote:

>I will try scanning each of the transports separately, although I
>can't see a reason why this should be different from scanning all of
>the existing ones ?

You'd think so, but digging back into those dark recesses, I'm fairly
sure I had to scan each one separately.

--
Simon Hobson

Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed
author Gladys Hobson. Novels - poetry - short stories - ideal as
Christmas stocking fillers. Some available as e-books.
_______________________________________________
mythtv-users mailing list
mythtv-users [at] mythtv
http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

terry1 at beam

Jul 11, 2010, 10:23 PM

Post #11 of 15 (1049 views)
Permalink

Re: MtrhTv: Uk Mendip Transmitter issues [In reply to]

On 11/07/10 22:43, Simon Hobson wrote:
> Terry Barnaby wrote:
>
>> I will try scanning each of the transports separately, although I
>> can't see a reason why this should be different from scanning all of
>> the existing ones ?
>
> You'd think so, but digging back into those dark recesses, I'm fairly
> sure I had to scan each one separately.
>
Ok, I tried scanning the transports 1 by 1. All channels where found
including all those on my problematic Multiplex. But still I cannot view
any channels on the problematic multiplex with MythTv. tzap/mplayer
is fine.
Maybe I will try rolling my own RPM's from SVN again ...
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terry1 at beam

Jul 11, 2010, 11:17 PM

Post #12 of 15 (1051 views)
Permalink

Re: MtrhTv: Uk Mendip Transmitter issues [In reply to]

On 12/07/10 06:23, Terry Barnaby wrote:
> On 11/07/10 22:43, Simon Hobson wrote:
>> Terry Barnaby wrote:
>>
>>> I will try scanning each of the transports separately, although I
>>> can't see a reason why this should be different from scanning all of
>>> the existing ones ?
>>
>> You'd think so, but digging back into those dark recesses, I'm fairly
>> sure I had to scan each one separately.
>>
> Ok, I tried scanning the transports 1 by 1. All channels where found
> including all those on my problematic Multiplex. But still I cannot view
> any channels on the problematic multiplex with MythTv. tzap/mplayer
> is fine.
> Maybe I will try rolling my own RPM's from SVN again ...
> _______________________________________________
> mythtv-users mailing list
> mythtv-users [at] mythtv
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
After a bit more googling, I came up with someone having this
problem due to incorrect PMT info being transmitted. I did a
dvbsnoop -s pidscan on the Mendip A Multiplex when tuned to ITV3
and got the attached file.

To my untrained eye this looks wrong.
Anyone with knowledge on this ?

Cheers

Terry

Attachments:

DvbSnoop.txt (5.93 KB)

terry1 at beam

Jul 12, 2010, 2:46 PM

Post #13 of 15 (1022 views)
Permalink

Re: MtrhTv: Uk Mendip Transmitter issues [In reply to]

On 12/07/10 07:17, Terry Barnaby wrote:
> On 12/07/10 06:23, Terry Barnaby wrote:
>> On 11/07/10 22:43, Simon Hobson wrote:
>>> Terry Barnaby wrote:
>>>
>>>> I will try scanning each of the transports separately, although I
>>>> can't see a reason why this should be different from scanning all of
>>>> the existing ones ?
>>>
>>> You'd think so, but digging back into those dark recesses, I'm fairly
>>> sure I had to scan each one separately.
>>>
>> Ok, I tried scanning the transports 1 by 1. All channels where found
>> including all those on my problematic Multiplex. But still I cannot view
>> any channels on the problematic multiplex with MythTv. tzap/mplayer
>> is fine.
>> Maybe I will try rolling my own RPM's from SVN again ...
>> _______________________________________________
>> mythtv-users mailing list
>> mythtv-users [at] mythtv
>> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
> After a bit more googling, I came up with someone having this
> problem due to incorrect PMT info being transmitted. I did a
> dvbsnoop -s pidscan on the Mendip A Multiplex when tuned to ITV3
> and got the attached file.
>
> To my untrained eye this looks wrong.
> Anyone with knowledge on this ?
>
> Cheers
>
>
> Terry

Ok, I have finally found the problem. The transportid for the Virgin1
Multiplex was incorrect in the dtv_multiplex database table. There is no
way of editing this using mythtvsetup, but it has to be correct.
I guess I did a full scan and then edited some of the incorrect
multiplexes (neighbouring transmitters) to to right values for
the local transmitter. Unfortunately the transportid was not changed.
I consider this a bug in either mythtvsetup by not allowing it
to be edited or in the mythtv SDT parser as it could find out the
correct transportid for the stream it is decoding.
I'm not sure how you would find the correct transportid value except
by using dvbsnoop...

Cheers

Terry
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J.Pilk at tesco

Jul 13, 2010, 1:43 AM

Post #14 of 15 (1019 views)
Permalink

Re: MtrhTv: Uk Mendip Transmitter issues [In reply to]

>
> Ok, I have finally found the problem. The transportid for the Virgin1
> Multiplex was incorrect in the dtv_multiplex database table. There is no
> way of editing this using mythtvsetup, but it has to be correct.
> I guess I did a full scan and then edited some of the incorrect
> multiplexes (neighbouring transmitters) to to right values for
> the local transmitter. Unfortunately the transportid was not changed.
> I consider this a bug in either mythtvsetup by not allowing it
> to be edited or in the mythtv SDT parser as it could find out the
> correct transportid for the stream it is decoding.
> I'm not sure how you would find the correct transportid value except
> by using dvbsnoop...
>
> Cheers
>
>
> Terry

Good to know you've identified the problem: have you got it working
now, and if so how? Did a scan of some sort within MythTV do the job or
have you _needed_ other tools?

John P

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terry1 at beam

Jul 14, 2010, 10:23 AM

Post #15 of 15 (994 views)
Permalink

Re: MtrhTv: Uk Mendip Transmitter issues [In reply to]

On 13/07/10 09:43, John Pilkington wrote:
>
>>
>> Ok, I have finally found the problem. The transportid for the Virgin1
>> Multiplex was incorrect in the dtv_multiplex database table. There is no
>> way of editing this using mythtvsetup, but it has to be correct.
>> I guess I did a full scan and then edited some of the incorrect
>> multiplexes (neighbouring transmitters) to to right values for
>> the local transmitter. Unfortunately the transportid was not changed.
>> I consider this a bug in either mythtvsetup by not allowing it
>> to be edited or in the mythtv SDT parser as it could find out the
>> correct transportid for the stream it is decoding.
>> I'm not sure how you would find the correct transportid value except
>> by using dvbsnoop...
>>
>> Cheers
>>
>>
>> Terry
>
> Good to know you've identified the problem: have you got it working now,
> and if so how? Did a scan of some sort within MythTV do the job or have
> you _needed_ other tools?
>
> John P
>
> _______________________________________________
> mythtv-users mailing list
> mythtv-users [at] mythtv
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

Yes, its all fully working now.

Basically I downloaded and built dvbsnoop to look at the packets
from the multiplex when tuned in with tzap.
So I ran "tzap -r -c channels.conf "Virgin1".
In a separate window I ran "dvbsnoop -s pidscan".
Then I ran "dvbsnoop -n 1 -nph 0x0103" where 0x0103 was the pid
of the SDT.
I had to run this a number of times as multiple SDT's are sent
for neighbouring multiplexes until the one for this multiplex
is sent (listed as such, can't quite remember the wording).
Within the SDT is the transportid.
I then edited the Mysql database using "mysql" to set the
correct transportid in the dvb_multiplex for the multiplex
in question.

There is probably a better way of finding the transportid, also
mythtv must determine and set this automatically from a full
channel scan, so maybe it can determine this automatically
some how (set transportid to 0/null ?? ) ??

Cheers

Terry
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