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Upnp, dlna, interval Upnp updates on multicast 239.255.255.250 port 1900

 

 

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ole_rydahl at qp12

Aug 29, 2010, 9:15 AM

Post #1 of 10 (2429 views)
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Upnp, dlna, interval Upnp updates on multicast 239.255.255.250 port 1900

I tried to decrease the interval between the Upnp updates (multicast) made
by the mythTV backend. The default seems to be 30 minutes.

The problem: After turning on a dlna capable TV-set (Samsung LE32C650) it
takes up to 30 minutes before the TV-set is aware of the backend and I have
access to the recordings.

I modified "Upnp Media Update Time" using mythTV Setup to 5 minutes. From
the backend log it is clear that something is then done every 5 minutes, but
the updates on the multicast address is unchanged - 30 minutes (Captured by
Wireshark).

Am I barking up the wrong tree?

Thanks!

/Ole


raymond at wagnerrp

Aug 29, 2010, 9:19 AM

Post #2 of 10 (2368 views)
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Re: Upnp, dlna, interval Upnp updates on multicast 239.255.255.250 port 1900 [In reply to]

On 8/29/2010 12:15, Ole Rydahl wrote:
>
> I modified "Upnp Media Update Time" using mythTV Setup to 5 minutes.
> From the backend log it is clear that something is then done every 5
> minutes, but the updates on the multicast address is unchanged - 30
> minutes (Captured by Wireshark).
>

The UPnP server in MythTV performs its own scan of video content stored
in MythVideo, rather than using that in the database. The 'media update
time' is how often it will run that scan. It has nothing to do with how
frequent your TV will refresh its listing.


oliver.greg at gmail

Aug 29, 2010, 9:52 AM

Post #3 of 10 (2362 views)
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Re: Upnp, dlna, interval Upnp updates on multicast 239.255.255.250 port 1900 [In reply to]

On Sun, Aug 29, 2010 at 11:19 AM, Raymond Wagner <raymond [at] wagnerrp> wrote:
> On 8/29/2010 12:15, Ole Rydahl wrote:
>
> I modified “Upnp Media Update Time” using mythTV Setup to 5 minutes. From
> the backend log it is clear that something is then done every 5 minutes, but
> the updates on the multicast address is unchanged - 30 minutes (Captured by
> Wireshark).
>
> The UPnP server in MythTV performs its own scan of video content stored in
> MythVideo, rather than using that in the database.  The 'media update time'
> is how often it will run that scan.  It has nothing to do with how frequent
> your TV will refresh its listing.

I have several renderers as well as several servers in the house to
play with and I can say they all behave differently. Usually bouncing
the multicast address is the safest way to get the renderer to
*notice* a new or modified server. Most of my renderers appear to
poll the device for capabilities and listings every time I ask for
info though. I do not have any that run off of any type of cache
(verified previously with tcpdumps) which actually upset me because I
was using wireless at that time and was trying to decrease traffic..
No such luck.
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ole_rydahl at qp12

Aug 29, 2010, 10:06 AM

Post #4 of 10 (2374 views)
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Re: Upnp, dlna, interval Upnp updates on multicast 239.255.255.250 port 1900 [In reply to]

>>On 8/29/2010 12:15, Ole Rydahl wrote:
>>I modified Upnp Media Update Time using mythTV Setup to 5 minutes. From
the backend log it is >>clear that something is then done every 5 minutes,
but the updates on the multicast address is >>unchanged - 30 minutes
(Captured by Wireshark).

>The UPnP server in MythTV performs its own scan of video content stored in
MythVideo, rather than >using that in the database. The 'media update time'
is how often it will run that scan. It has >nothing to do with how frequent
your TV will refresh its listing.

Thanks! I was close to that conclusion too. Any way of decreasing the time
between MythTv-backend sends out Upnp announcements of its presence?

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oliver.greg at gmail

Aug 29, 2010, 11:32 AM

Post #5 of 10 (2351 views)
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Re: Upnp, dlna, interval Upnp updates on multicast 239.255.255.250 port 1900 [In reply to]

On Sun, Aug 29, 2010 at 12:06 PM, Ole Rydahl <ole_rydahl [at] qp12> wrote:
>>>On 8/29/2010 12:15, Ole Rydahl wrote:
>>>I modified “Upnp Media Update Time” using mythTV Setup to 5 minutes. From
> the backend log it is >>clear that something is then done every 5 minutes,
> but the updates on the multicast address is >>unchanged - 30 minutes
> (Captured by Wireshark).
>
>>The UPnP server in MythTV performs its own scan of video content stored in
> MythVideo, rather than >using that in the database.  The 'media update time'
> is how often it will run that scan.  It has >nothing to do with how frequent
> your TV will refresh its listing.
>
> Thanks! I was close to that conclusion too. Any way of decreasing the time
> between MythTv-backend sends out Upnp announcements of its presence?

AFAIK, UPnP does not do that.. It broadcasts to the multicast address
that it is there and clients request the info. If the clients cache
what they get I assume they are breaking some rules - the protocol is
not supposed to work that way. Have you restarted mythtv-backend
after you changed the settings? That setting does not broadcast
anything (or it should not) - I assume it just updates it's internal
listing so that when requested, new info is then sent out. I assume
it requires a backend restart, but not positive.

I guess I should have mentioned that I do not have any of them running
any longer on my mythtv network. I only keep it running on the
directv dvr network so they can watch stuff.. That's soon to be gone
as soon as I get this last machine going..
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ole_rydahl at qp12

Aug 29, 2010, 12:24 PM

Post #6 of 10 (2356 views)
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Re: Upnp, dlna, interval Upnp updates on multicast 239.255.255.250 port 1900 [In reply to]

> -----Oprindelig meddelelse-----
> Fra: mythtv-users-bounces [at] mythtv [mailto:mythtv-users-

> > Thanks! I was close to that conclusion too. Any way of decreasing
> the time
> > between MythTv-backend sends out Upnp announcements of its
> presence?
>
> AFAIK, UPnP does not do that.. It broadcasts to the multicast
> address
> that it is there and clients request the info. If the clients cache
> what they get I assume they are breaking some rules - the protocol is
> not supposed to work that way. Have you restarted mythtv-backend
> after you changed the settings? That setting does not broadcast
> anything (or it should not) - I assume it just updates it's internal
> listing so that when requested, new info is then sent out. I assume
> it requires a backend restart, but not positive.
>
[Ole Rydahl:]
Thanks! Yes I have restarted and on restart a Upnp announcement is sent out as expected - but refreshed only every 30 minutes. A soon as the client (the TV set) knows about the mythtv backend from the Upnp announcement (multicast) everything (almost!) works like a charm. I think Raymond Wagner is spot on when he points out that the “Upnp Media Update Time” setting is for other purposes then the one I am looking for.

Now, in worst case - after power up of the TV-set - I have to wait for 30 minutes before the TV-set is finally informed of the MythTV backends presence by the Upnp multicast. Routers and Windows running Upnp/dlna seems to do an announcement (multicast) every 10 minutes. I would like to have my MythTV backend do it - say every 5 minutes.

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oliver.greg at gmail

Aug 29, 2010, 12:32 PM

Post #7 of 10 (2360 views)
Permalink
Re: Upnp, dlna, interval Upnp updates on multicast 239.255.255.250 port 1900 [In reply to]

On Sun, Aug 29, 2010 at 2:24 PM, Ole Rydahl <ole_rydahl [at] qp12> wrote:
>
>
>> -----Oprindelig meddelelse-----
>> Fra: mythtv-users-bounces [at] mythtv [mailto:mythtv-users-
>
>> > Thanks! I was close to that conclusion too. Any way of decreasing
>> the time
>> > between MythTv-backend sends out Upnp announcements of its
>> presence?
>>
>> AFAIK, UPnP does not do that..  It broadcasts to the multicast
>> address
>> that it is there and clients request the info.  If the clients cache
>> what they get I assume they are breaking some rules - the protocol is
>> not supposed to work that way.  Have you restarted mythtv-backend
>> after you changed the settings?  That setting does not broadcast
>> anything (or it should not) - I assume it just updates it's internal
>> listing so that when requested, new info is then sent out.  I assume
>> it requires a backend restart, but not positive.
>>
> [Ole Rydahl:]
> Thanks! Yes I have restarted and on restart a Upnp announcement is sent out as expected - but refreshed only every 30 minutes. A soon as the client (the TV set) knows about the mythtv backend from the Upnp announcement (multicast) everything (almost!) works like a charm. I think Raymond Wagner is spot on when he points out that the “Upnp Media Update Time” setting is for other purposes then the one I am looking for.
>
> Now, in worst case - after power up of the TV-set - I have to wait for 30 minutes before the TV-set is finally informed of the MythTV backends presence by the Upnp multicast. Routers and Windows running Upnp/dlna seems to do an announcement (multicast) every 10 minutes. I would like to have my MythTV backend do it - say every 5 minutes.
>

Hmmmm, my directTV dvrs display either the removal or addition of the
backend as soon as I stop or start it. I just enabled upnp and tried
it... Current listings are available immediately. Can you try
another upnp server on the same network to see if it may be your tv..
I cannot imagine a server that does not tell the network it is
available as soon as it starts - which is what you are saying is
happening.. And I can definitely say it is not working that way here
- it sounds like the TV is needing the refresh - not the server...
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raymond at wagnerrp

Aug 29, 2010, 12:42 PM

Post #8 of 10 (2349 views)
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Re: Upnp, dlna, interval Upnp updates on multicast 239.255.255.250 port 1900 [In reply to]

On 8/29/2010 15:24, Ole Rydahl wrote:
> Now, in worst case - after power up of the TV-set - I have to wait for 30 minutes before the TV-set is finally informed of the MythTV backends presence by the Upnp multicast. Routers and Windows running Upnp/dlna seems to do an announcement (multicast) every 10 minutes. I would like to have my MythTV backend do it - say every 5 minutes.

An announcement should be unnecessary. UPnP renderers are supposed to
query that address and port, and all matching devices respond to the
render point with their relevant information.
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ole_rydahl at qp12

Aug 29, 2010, 3:13 PM

Post #9 of 10 (2349 views)
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Re: Upnp, dlna, interval Upnp updates on multicast 239.255.255.250 port 1900 [In reply to]

>
> On 8/29/2010 15:24, Ole Rydahl wrote:
> > Now, in worst case - after power up of the TV-set - I have to wait
> for 30 minutes before the TV-set is finally informed of the MythTV
> backends presence by the Upnp multicast. Routers and Windows running
> Upnp/dlna seems to do an announcement (multicast) every 10 minutes. I
> would like to have my MythTV backend do it - say every 5 minutes.
>
> An announcement should be unnecessary. UPnP renderers are supposed
> to
> query that address and port, and all matching devices respond to the
> render point with their relevant information.
[Ole Rydahl:]
Thanks! You have got a point! I did the following test - setting up a
Windows media player on a xp-system and some dlna on top. Its services are
recognized immediately after power cycling the TV-set!

Guess I'll have to power up Wireshark and record in detail why the behaviors
differ!

Oh dear - barking up two wrong trees during just one evening! ...

Thanks again!!

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MythTv at TheBlains

Aug 29, 2010, 6:42 PM

Post #10 of 10 (2328 views)
Permalink
Re: Upnp, dlna, interval Upnp updates on multicast 239.255.255.250 port 1900 [In reply to]

> [Ole Rydahl:]
> Thanks! You have got a point! I did the following test - setting up a
Windows
> media player on a xp-system and some dlna on top. Its services are
> recognized immediately after power cycling the TV-set!
>
> Guess I'll have to power up Wireshark and record in detail why the
behaviors
> differ!
>
> Oh dear - barking up two wrong trees during just one evening! ...
>
> Thanks again!!

Like others have said, the upnp control point should perform an M-SEARCH and
Mythbackend should answer. Mythbackend also, per the upnp spec, advertises
it's availability using multicast. The advertisement is marked to expire
the default amount of time of 60 minute. And according to the spec, it
re-advertises 1/2 that time (which explains why you see it every 30
minutes).

It can be changed by modifying/adding an entry to the settings table. The
key is "UPnP/SSDP/MaxAge" and is in seconds.

FYI: the line that uses it is:

m_nMaxAge = UPnp::g_pConfig->GetValue( "UPnP/SSDP/MaxAge" ,
3600 );

in upnptasknotify.cpp.

David.

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