Mailing List Archive: MythTV: Users

BBC THREE/FOUR

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dweller at the-threshold

Feb 4, 2004, 1:18 AM

Post #1 of 18 (3076 views)
Permalink

BBC THREE/FOUR

Lo Chaps,

Am having another play at setting up the Mythtv system for girlfriend
approval and I'm having problems with some of the part-time channels
like BBC THREE and BBC FOUR on my nova-t DVB system. I've the latest cvs
version build and running as of this morning at 7am (Keen or what?).

Basicly if I watchtv or change to bbc four I get the following
mythbackend message:-

2004-02-04 08:09:32 DVB#1 WARNING - No data from card in 1 second.

From the frontend I get a blackscreen and the following collection of
messages

2004-02-04 08:08:50 Connecting to backend server: 127.0.0.1:6543 (try 1
of 3)
2004-02-04 08:08:50 Using protocol version 2
2004-02-04 08:08:50 Using protocol version 2
2004-02-04 08:08:50 Using protocol version 2
taking too long to be allowed to read..
taking too long to be allowed to read..
taking too long to be allowed to read..
Waited 2 seconds for data to become available, waiting again...
Waited 2 seconds for data to become available, waiting again...
Waited 2 seconds for data to become available, waiting again...
Waited 2 seconds for data to become available, waiting again...

Now is this because of the part time nature of BBC three and four and an
intolorance in the mythtv dvb code or is it because I've a flawed config.

Regards
Simon

--
The idle mind knows not what it is it wants.
-- Quintus Ennius
--
This email and any attachments hereto are strictly confidential and
intended solely for the addressee. It may contain information which is
covered by legal, professional or other privilege. If you are not the
indended addressee, you must not disclose, forward, copy or take any
action in reliance of this email or attachments. If you have received
this email in error, please notify us as soon as possible.

dweller at the-threshold

Feb 4, 2004, 1:42 AM

Post #2 of 18 (3059 views)
Permalink

Re: BBC THREE/FOUR [In reply to]

Addtional

For some reason it looks like a lot of my dvb settings got rubbished..I
suspect it had something todo with the last mythtv revision. But then
again I probably should have taken a database snapshot as I'm running
with the bleeding edge.

However seem to see mythtv fall over a lot now just by changing channels.

mythtv: xvmcvideo.c:121: XVMC_field_start: Assertion `last->state & 2'
failed.
2004-02-04 08:38:20 GetNextFreeFrame() served a busy frame. Dropping.
#Frames=4/7.
zsh: 21234 killed mythtv

Regards
Simon

--
The hardest thing in the world to understand is the income tax.
-- Albert Einstein

ke-aa at frisurf

Feb 4, 2004, 1:43 AM

Post #3 of 18 (3061 views)
Permalink

RE: BBC THREE/FOUR [In reply to]

Hi,

Simon wrote:
> Lo Chaps,
>
> Am having another play at setting up the Mythtv system for
> girlfriend approval and I'm having problems with some of
> the part-time channels like BBC THREE and BBC FOUR on my
> nova-t DVB system. I've the latest cvs version build and
> running as of this morning at 7am (Keen or what?).
>
> Basicly if I watchtv or change to bbc four I get the following
> mythbackend message:-
>
> 2004-02-04 08:09:32 DVB#1 WARNING - No data from card
> in 1 second.
>
[snip]
>
> Now is this because of the part time nature of BBC three and
> four and an intolorance in the mythtv dvb code or is it because
> I've a flawed config.

I've actually not been annoyed enough to do anything about the
fact that sometimes my card/mythbackend locks in this loop
(I do not have part time channels available here, but once
in a great while my cam refuses to start decrypting..).

Your correct as that is partly a ignorance in the dvb code, and
partly and ignorance in the mythtv recording code as a whole
that the wait loops are mostly hardlocked. It should be fairly
trivial to do a clean fix of the problem though, feel free..

Kenneth

_______________________________________________
mythtv-users mailing list
mythtv-users [at] mythtv
http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

dweller at the-threshold

Feb 4, 2004, 2:00 AM

Post #4 of 18 (3055 views)
Permalink

Re: BBC THREE/FOUR [In reply to]

Kenneth Aafløy wrote:
>>Now is this because of the part time nature of BBC three and
>>four and an intolorance in the mythtv dvb code or is it because
>>I've a flawed config.
>
>
> I've actually not been annoyed enough to do anything about the
> fact that sometimes my card/mythbackend locks in this loop
> (I do not have part time channels available here, but once
> in a great while my cam refuses to start decrypting..).
>
> Your correct as that is partly a ignorance in the dvb code, and
> partly and ignorance in the mythtv recording code as a whole
> that the wait loops are mostly hardlocked. It should be fairly
> trivial to do a clean fix of the problem though, feel free..
>
> Kenneth

I'll have a play when the other half isn't looking, been looking for an
excuse to help out.. <Chuckle>.

Simon

--
The hardest thing in the world to understand is the income tax.
-- Albert Einstein

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malc at porsche

Feb 4, 2004, 2:34 AM

Post #5 of 18 (3016 views)
Permalink

Re: BBC THREE/FOUR [In reply to]

Simon,

Although I agree with point about the loops and the general behaviour of
the DVB code (and feel free to fix!), I think your problem is slightly
different.

The "channel" always transmitts it's either CBBC / C Beebies or
BBC3/BBC4. The crafty b*****rs at the beeb do the following

scan results when THREE is off the air
BBC
THREE:754166670:INVERSION_OFF:BANDWIDTH_8_MHZ:FEC_3_4:FEC_3_4:QAM_16:TRANSMISSION_MODE_2K:GUARD_INTERVAL_1_32:HIERARCHY_NONE:0:0:4351

scan results when THREE is transmitting

BBC
THREE:754166670:INVERSION_OFF:BANDWIDTH_8_MHZ:FEC_3_4:FEC_3_4:QAM_16:TRANSMISSION_MODE_2K:GUARD_INTERVAL_1_32:HIERARCHY_NONE:620:621:4351

If you look carefully the video and audio pids are 0 when it is off the
air. When did you run scan?

I would check your pids. I've been working with Daniel on a script that
takes the output of scan and loads up the various tables. I could let
you have a copy. (It's not complete yet).

Back to the original problem:

Ideally the backend should respond indicating no program data is available.
It should also cope with different apids and the vpid/apid not being
present (e.g. no vpid = radio station)

-malc-

Simon at the Threshold wrote:

> Lo Chaps,
>
> Am having another play at setting up the Mythtv system for girlfriend
> approval and I'm having problems with some of the part-time channels
> like BBC THREE and BBC FOUR on my nova-t DVB system. I've the latest
> cvs version build and running as of this morning at 7am (Keen or what?).
>
> Basicly if I watchtv or change to bbc four I get the following
> mythbackend message:-
>
> 2004-02-04 08:09:32 DVB#1 WARNING - No data from card in 1 second.
>
> From the frontend I get a blackscreen and the following collection of
> messages
>
> 2004-02-04 08:08:50 Connecting to backend server: 127.0.0.1:6543 (try
> 1 of 3)
> 2004-02-04 08:08:50 Using protocol version 2
> 2004-02-04 08:08:50 Using protocol version 2
> 2004-02-04 08:08:50 Using protocol version 2
> taking too long to be allowed to read..
> taking too long to be allowed to read..
> taking too long to be allowed to read..
> Waited 2 seconds for data to become available, waiting again...
> Waited 2 seconds for data to become available, waiting again...
> Waited 2 seconds for data to become available, waiting again...
> Waited 2 seconds for data to become available, waiting again...
>
> Now is this because of the part time nature of BBC three and four and
> an intolorance in the mythtv dvb code or is it because I've a flawed
> config.
>
> Regards
> Simon
>
>
>------------------------------------------------------------------------
>
>_______________________________________________
>mythtv-users mailing list
>mythtv-users [at] mythtv
>http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>

dweller at the-threshold

Feb 4, 2004, 2:52 AM

Post #6 of 18 (3055 views)
Permalink

Re: BBC THREE/FOUR [In reply to]

Malcolm Smith wrote:
> Simon,
>
> Although I agree with point about the loops and the general behaviour of
> the DVB code (and feel free to fix!), I think your problem is slightly
> different.
>
[snip]

> If you look carefully the video and audio pids are 0 when it is off the
> air. When did you run scan?

Yes that's a good one, I fell for that one the first time I installed,
was only when I reran scan in the evening it finaly dawned on me how the
two channels where being broadcast (or not as the case maybe).
>
> I would check your pids. I've been working with Daniel on a script that
> takes the output of scan and loads up the various tables. I could let
> you have a copy. (It's not complete yet).

That would be the most obvious solution.. Might I suggest for a future
direction that the mythtv setup program be enhanced to allow a external
tuner application to be run to do this. That way it should be possible
to automate the process for other DVB types and even analog if somebody
knocks together the scan/detection app.

> Back to the original problem:
>
> Ideally the backend should respond indicating no program data is available.
> It should also cope with different apids and the vpid/apid not being
> present (e.g. no vpid = radio station)

Yes I'd noticed that mythtv wasn't hot with the radio channels.. I'm not
promising anything as my forte is real-time C code/distributed systems.
So I suspect my milage may vary when I try to hack Video based/C++. So
we will see..(Said the blind man)..

Simon

--
The hardest thing in the world to understand is the income tax.
-- Albert Einstein

mailing-lists at scantech

Feb 4, 2004, 3:07 AM

Post #7 of 18 (3064 views)
Permalink

Re: BBC THREE/FOUR [In reply to]

-----Original Message-----
Sent: Wednesday 04/02/2004 08:18:38
Subject: [mythtv-users] BBC THREE/FOUR

>Lo Chaps,
>
>Am having another play at setting up the Mythtv system for girlfriend
>approval and I'm having problems with some of the part-time channels
>like BBC THREE and BBC FOUR on my nova-t DVB system. I've the latest cvs
>version build and running as of this morning at 7am (Keen or what?).
>
>Basicly if I watchtv or change to bbc four I get the following
>mythbackend message:-
>
>2004-02-04 08:09:32 DVB#1 WARNING - No data from card in 1 second.
>
> From the frontend I get a blackscreen and the following collection of
>messages
>
>2004-02-04 08:08:50 Connecting to backend server: 127.0.0.1:6543 (try 1
>of 3)
>2004-02-04 08:08:50 Using protocol version 2
>2004-02-04 08:08:50 Using protocol version 2
>2004-02-04 08:08:50 Using protocol version 2
>taking too long to be allowed to read..
>taking too long to be allowed to read..
>taking too long to be allowed to read..
>Waited 2 seconds for data to become available, waiting again...
>Waited 2 seconds for data to become available, waiting again...
>Waited 2 seconds for data to become available, waiting again...
>Waited 2 seconds for data to become available, waiting again...
>
>Now is this because of the part time nature of BBC three and four and an
>intolorance in the mythtv dvb code or is it because I've a flawed config.
>
>Regards
>Simon
>
>--
>The idle mind knows not what it is it wants.
> -- Quintus Ennius
>--
>This email and any attachments hereto are strictly confidential and
>intended solely for the addressee. It may contain information which is
>covered by legal, professional or other privilege. If you are not the
>indended addressee, you must not disclose, forward, copy or take any
>action in reliance of this email or attachments. If you have received
>this email in error, please notify us as soon as possible.
>
>
Does the card provide all the DVB Tables to Myth ? I'm not a programmer, don't have a DVB Card, but I do understand DVB Tables.

There should be a "running status" flag in either the SDT or EIT tables. This should be de-active when BBC3 is off the air indicating to the decoder that it should not try to tune the service. Myth could use this to display a message such as "not available at this time" ??

Hope this helps.

Pete
_______________________________________________
mythtv-users mailing list
mythtv-users [at] mythtv
http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

paul_woodward at fastnet

Feb 4, 2004, 3:19 AM

Post #8 of 18 (3050 views)
Permalink

Re: Re: BBC THREE/FOUR [In reply to]

At one stage I had the radio working by setting the video pid to that of another channel on the same multiplex - it kept myth happy!

Paul

> --===============1780832790==
> Content-Type: text/plain; charset=us-ascii; format=flowed
> Content-Transfer-Encoding: 7bit
>
> Malcolm Smith wrote:
> > Simon,
> >
> > Although I agree with point about the loops and the general behaviour of
> > the DVB code (and feel free to fix!), I think your problem is slightly
> > different.
> >
> [snip]
>
> > If you look carefully the video and audio pids are 0 when it is off the
> > air. When did you run scan?
>
> Yes that's a good one, I fell for that one the first time I installed,
> was only when I reran scan in the evening it finaly dawned on me how the
> two channels where being broadcast (or not as the case maybe).
> >
> > I would check your pids. I've been working with Daniel on a script that
> > takes the output of scan and loads up the various tables. I could let
> > you have a copy. (It's not complete yet).
>
> That would be the most obvious solution.. Might I suggest for a future
> direction that the mythtv setup program be enhanced to allow a external
> tuner application to be run to do this. That way it should be possible
> to automate the process for other DVB types and even analog if somebody
> knocks together the scan/detection app.
>
> > Back to the original problem:
> >
> > Ideally the backend should respond indicating no program data is available.
> > It should also cope with different apids and the vpid/apid not being
> > present (e.g. no vpid = radio station)
>
> Yes I'd noticed that mythtv wasn't hot with the radio channels.. I'm not
> promising anything as my forte is real-time C code/distributed systems.
> So I suspect my milage may vary when I try to hack Video based/C++. So
> we will see..(Said the blind man)..
>
> Simon
>
> --
> The hardest thing in the world to understand is the income tax.
> -- Albert Einstein
>
>
>
> --===============1780832790==
> Content-Type: text/plain; charset="iso-8859-1"
> MIME-Version: 1.0
> Content-Transfer-Encoding: quoted-printable
> Content-Disposition: inline
>
> _______________________________________________
> mythtv-users mailing list
> mythtv-users [at] mythtv
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>
> --===============1780832790==--
>

_______________________________________________
mythtv-users mailing list
mythtv-users [at] mythtv
http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

ke-aa at frisurf

Feb 4, 2004, 3:38 AM

Post #9 of 18 (3034 views)
Permalink

RE: BBC THREE/FOUR [In reply to]

Simon wrote:
> Malcolm Smith wrote:
> > I would check your pids. I've been working with Daniel on a
> > script that takes the output of scan and loads up the various
> > tables. I could let you have a copy. (It's not complete yet).
>
> That would be the most obvious solution.. Might I suggest for
> a future direction that the mythtv setup program be enhanced
> to allow a external tuner application to be run to do this.
> That way it should be possible to automate the process for
> other DVB types and even analog if somebody knocks together
> the scan/detection app.

I have always had `in house` code in mind. If someone would
write simple code to parse/import the vdr .conf files it's
acceptable, and even a extra feature. It should be really
simple to write also, since it's just a bounch of :::::::::'s
and newlines + the parameter wording. I might consider helping
with a rewrite of the parsers in DVBChannel and DB if someone
writes the logic for setup.

If this get's done, all someone have to do is scan before
running mythsetup (verifying that the card works at the
same time), and import the channel.conf. If someone already
has a 1000+ line channel.conf from vdr, they could just
import and be set :)

Ciao,
Kenneth

_______________________________________________
mythtv-users mailing list
mythtv-users [at] mythtv
http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

ke-aa at frisurf

Feb 4, 2004, 3:57 AM

Post #10 of 18 (3055 views)
Permalink

RE: BBC THREE/FOUR [In reply to]

Hi,

Pete wrote:
> Does the card provide all the DVB Tables to Myth ? I'm not
> a programmer, don't have a DVB Card, but I do understand DVB Tables.

Yes indeed it does.

> There should be a "running status" flag in either the SDT or
> EIT tables. This should be de-active when BBC3 is off the
> air indicating to the decoder that it should not try to tune
> the service. Myth could use this to display a message such
> as "not available at this time" ??
>
> Hope this helps.

Quote from 'Specification for SI' - ETSI EN 300 468:
"
The RST (see table 10) allows accurate and rapid updating of
the timing status of one or more events. This may be necessary
when an event starts early or late due to scheduling changes.
The use of a separate table enables fast updating mechanism
to be achieved.
"

I assume that you are reffering to the running_status field
of this table? Most providers (as far as I know) are not
activly updating this table, so the information in it is
close to useless =(

Anyways, this would not have solved tuning problems (lack
of signal, because then we never would have received it).

Kenneth

_______________________________________________
mythtv-users mailing list
mythtv-users [at] mythtv
http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

paul_woodward at fastnet

Feb 4, 2004, 4:10 AM

Post #11 of 18 (3040 views)
Permalink

Re: RE: BBC THREE/FOUR [In reply to]

> Simon wrote:
> > Malcolm Smith wrote:
> > > I would check your pids. I've been working with Daniel on a
> > > script that takes the output of scan and loads up the various
> > > tables. I could let you have a copy. (It's not complete yet).
> >
> > That would be the most obvious solution.. Might I suggest for
> > a future direction that the mythtv setup program be enhanced
> > to allow a external tuner application to be run to do this.
> > That way it should be possible to automate the process for
> > other DVB types and even analog if somebody knocks together
> > the scan/detection app.
>
> I have always had `in house` code in mind. If someone would
> write simple code to parse/import the vdr .conf files it's
> acceptable, and even a extra feature. It should be really
> simple to write also, since it's just a bounch of :::::::::'s
> and newlines + the parameter wording. I might consider helping
> with a rewrite of the parsers in DVBChannel and DB if someone
> writes the logic for setup.
>
> If this get's done, all someone have to do is scan before
> running mythsetup (verifying that the card works at the
> same time), and import the channel.conf. If someone already
> has a 1000+ line channel.conf from vdr, they could just
> import and be set :)
>
> Ciao,
> Kenneth
>

I'm slightly confused - I thought that the pids changed in real time to indicate the state of transmission. Isn't it therefore necessary to effectively scan on changing to that channel rather than at configuration time?

Pls correct me if I'm wrong.

_______________________________________________
mythtv-users mailing list
mythtv-users [at] mythtv
http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

malc at porsche

Feb 4, 2004, 4:19 AM

Post #12 of 18 (3044 views)
Permalink

Re: BBC THREE/FOUR [In reply to]

Yep that's exactly how I do it at present.

I also have a modified version of nuv_export to extract the mp3 data and
throw away the redundant video

Would be nice to have a "proper" solution

-malc-

Paul Woodward wrote:

>At one stage I had the radio working by setting the video pid to that of another channel on the same multiplex - it kept myth happy!
>
>Paul
>
>>--===============1780832790==
>>Content-Type: text/plain; charset=us-ascii; format=flowed
>>Content-Transfer-Encoding: 7bit
>>
>>Malcolm Smith wrote:
>>
>>>Simon,
>>>
>>>Although I agree with point about the loops and the general behaviour of
>>>the DVB code (and feel free to fix!), I think your problem is slightly
>>>different.
>>>
>>[snip]
>>
>>>If you look carefully the video and audio pids are 0 when it is off the
>>>air. When did you run scan?
>>>
>>Yes that's a good one, I fell for that one the first time I installed,
>>was only when I reran scan in the evening it finaly dawned on me how the
>>two channels where being broadcast (or not as the case maybe).
>>
>>>I would check your pids. I've been working with Daniel on a script that
>>>takes the output of scan and loads up the various tables. I could let
>>>you have a copy. (It's not complete yet).
>>>
>>That would be the most obvious solution.. Might I suggest for a future
>>direction that the mythtv setup program be enhanced to allow a external
>>tuner application to be run to do this. That way it should be possible
>>to automate the process for other DVB types and even analog if somebody
>>knocks together the scan/detection app.
>>
>>>Back to the original problem:
>>>
>>>Ideally the backend should respond indicating no program data is available.
>>>It should also cope with different apids and the vpid/apid not being
>>>present (e.g. no vpid = radio station)
>>>
>>Yes I'd noticed that mythtv wasn't hot with the radio channels.. I'm not
>>promising anything as my forte is real-time C code/distributed systems.
>>So I suspect my milage may vary when I try to hack Video based/C++. So
>>we will see..(Said the blind man)..
>>
>>Simon
>>
>>--
>>The hardest thing in the world to understand is the income tax.
>> -- Albert Einstein
>>
>>
>>
>>--===============1780832790==
>>Content-Type: text/plain; charset="iso-8859-1"
>>MIME-Version: 1.0
>>Content-Transfer-Encoding: quoted-printable
>>Content-Disposition: inline
>>
>>_______________________________________________
>>mythtv-users mailing list
>>mythtv-users [at] mythtv
>>http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>>
>>--===============1780832790==--
>>
>
>_______________________________________________
>mythtv-users mailing list
>mythtv-users [at] mythtv
>http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>

malc at porsche

Feb 4, 2004, 4:22 AM

Post #13 of 18 (3043 views)
Permalink

Re: BBC THREE/FOUR [In reply to]

Kenneth,

Here's the PERL that does this.....(I have to credit Daniel with the
major chunk of the code)

Can anyone turn this into a Qt / C++ thingy?

-malc-

Kenneth Aafløy wrote:

>Simon wrote:
>
>>Malcolm Smith wrote:
>>
>>>I would check your pids. I've been working with Daniel on a
>>>script that takes the output of scan and loads up the various
>>>tables. I could let you have a copy. (It's not complete yet).
>>>
>>That would be the most obvious solution.. Might I suggest for
>>a future direction that the mythtv setup program be enhanced
>>to allow a external tuner application to be run to do this.
>>That way it should be possible to automate the process for
>>other DVB types and even analog if somebody knocks together
>>the scan/detection app.
>>
>
>I have always had `in house` code in mind. If someone would
>write simple code to parse/import the vdr .conf files it's
>acceptable, and even a extra feature. It should be really
>simple to write also, since it's just a bounch of :::::::::'s
>and newlines + the parameter wording. I might consider helping
>with a rewrite of the parsers in DVBChannel and DB if someone
>writes the logic for setup.
>
>If this get's done, all someone have to do is scan before
>running mythsetup (verifying that the card works at the
>same time), and import the channel.conf. If someone already
>has a 1000+ line channel.conf from vdr, they could just
>import and be set :)
>
>Ciao,
>Kenneth
>
>
>_______________________________________________
>mythtv-users mailing list
>mythtv-users [at] mythtv
>http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>

Attachments:

dvb_insert_channs.pl (14.5 KB)

ke-aa at frisurf

Feb 4, 2004, 5:03 AM

Post #14 of 18 (3049 views)
Permalink

RE: RE: BBC THREE/FOUR [In reply to]

Paul Woodward wrote:
> I'm slightly confused - I thought that the pids changed in
> real time to indicate the state of transmission. Isn't it
> therefore necessary to effectively scan on changing to that
> channel rather than at configuration time?

That's obviously one way to do it (but I would make that an
example of how it should not be done). I've also got one of
those shared channels in my channel three, but this does not
change pids in the middle of the transmission.

One way to solve this is to add a autopid flag to the
dvb_channel table, and write a service description table
parser which does the job of updating the pids at the
beginning of a show and/or at a specified interval. Although
I would recomend having such a feature disabled as default,
because 99.9% of the channels have static pids. And it takes
some time before the table reach us, so that's yet another
delay on channel changes. There was such code (incomplete
though), in the earlier dvb-alpha releases of the mythtv-dvb
code (might still be archived).

Kenneth

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ke-aa at frisurf

Feb 4, 2004, 5:26 AM

Post #15 of 18 (3057 views)
Permalink

RE: DVB Channel.conf Import (WAS: BBC THREE/FOUR) [In reply to]

Malcolm,

> Here's the PERL that does this.....(I have to credit Daniel
> with the major chunk of the code)
>
> Can anyone turn this into a Qt / C++ thingy?

I guess, but the script was so nice, and perl is a dependency
because of xmltv, so with some finetuning and addition of czap,
I belive this should go into contrib. =)

Kenneth

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paul_woodward at fastnet

Feb 4, 2004, 5:51 AM

Post #16 of 18 (3043 views)
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Re: RE: RE: BBC THREE/FOUR [In reply to]

> Paul Woodward wrote:
> > I'm slightly confused - I thought that the pids changed in
> > real time to indicate the state of transmission. Isn't it
> > therefore necessary to effectively scan on changing to that
> > channel rather than at configuration time?
>
> That's obviously one way to do it (but I would make that an
> example of how it should not be done). I've also got one of
> those shared channels in my channel three, but this does not
> change pids in the middle of the transmission.
>
> One way to solve this is to add a autopid flag to the
> dvb_channel table, and write a service description table
> parser which does the job of updating the pids at the
> beginning of a show and/or at a specified interval. Although
> I would recomend having such a feature disabled as default,
> because 99.9% of the channels have static pids. And it takes
> some time before the table reach us, so that's yet another
> delay on channel changes. There was such code (incomplete
> though), in the earlier dvb-alpha releases of the mythtv-dvb
> code (might still be archived).
>
> Kenneth

My C/C++ is way off the mark for doing this myself, but the auto pid idea sounds pretty good. I agree that doing it for every channel would be a bad idea.

One of my friends is a DVB guru, and I'm sure I remember him saying that the DVB pids info for all channels is transmitted on every multiplex. If this is the case could the updates be done automatically (if the tuner is in use) and hence no delays in changing channel.

Paul

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mailing-lists at scantech

Feb 4, 2004, 7:19 AM

Post #17 of 18 (3055 views)
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Re:RE: RE: BBC THREE/FOUR [In reply to]

-----Original Message-----
Sent: Wednesday 04/02/2004 13:03:30
Subject: RE: RE: [mythtv-users] BBC THREE/FOUR

>Paul Woodward wrote:
>> I'm slightly confused - I thought that the pids changed in
>> real time to indicate the state of transmission. Isn't it
>> therefore necessary to effectively scan on changing to that
>> channel rather than at configuration time?
>
>That's obviously one way to do it (but I would make that an
>example of how it should not be done). I've also got one of
>those shared channels in my channel three, but this does not
>change pids in the middle of the transmission.
>
>One way to solve this is to add a autopid flag to the
>dvb_channel table, and write a service description table
>parser which does the job of updating the pids at the
>beginning of a show and/or at a specified interval. Although
>I would recomend having such a feature disabled as default,
>because 99.9% of the channels have static pids. And it takes
>some time before the table reach us, so that's yet another
>delay on channel changes. There was such code (incomplete
>though), in the earlier dvb-alpha releases of the mythtv-dvb
>code (might still be archived).
>
>Kenneth
>
>
>_______________________________________________
>mythtv-users mailing list
>mythtv-users [at] mythtv
>http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

What about triggering on the version number in the tables ? This is how I would normally expect a STB to trigger table re-reads. I know most multiplexors do updates this way; ie,if the PMT version changes, then we expect the service to be changing PIDs. Same reasoning for any tables being processed.

I have not looked at the PSI/SI from the BBC in a while, but I do have access to an Acterna transport stream analyser. We have just moved offices so they are packed away at the moment, but the lab should be running again soon. I will be able do do any TS analysis then that you guys need.

Rgds,
Pete
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malc at porsche

Feb 4, 2004, 9:37 AM

Post #18 of 18 (3059 views)
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Re: DVB Channel.conf Import (WAS: BBC THREE/FOUR) [In reply to]

Kenneth,

Many thanks.

General appeal to better PERL coders than I... Improvements required:
1. The scripts tries to find a match between the channel name in
channels.conf and the channels table. If it can't it asks for search
terms. (e.g. tv_grab_uk_rt grabs BBC 3 but the channels.conf name is
THREE. The question handling is poor ... would be a lot tidier if...
2. The location of channels.conf is hard coded
3. The options for satellite vs terrestrial are not handled on the
command line
4. It has a "simulate" variable this should be driven from the command
line
5. Satellite handling is basic as yet.

Any input gratefully received.

-malc-

Kenneth Aafløy wrote:

>Malcolm,
>
>>Here's the PERL that does this.....(I have to credit Daniel
>>with the major chunk of the code)
>>
>>Can anyone turn this into a Qt / C++ thingy?
>>
>
>I guess, but the script was so nice, and perl is a dependency
>because of xmltv, so with some finetuning and addition of czap,
>I belive this should go into contrib. =)
>
>Kenneth
>
>
>_______________________________________________
>mythtv-users mailing list
>mythtv-users [at] mythtv
>http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>

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