Hi,
I have faced an issue related to RTP stream:
If the seq number and time of the received RTP packet is somehow reset (
while *ssrc* remains the *same*), playback is stopped
That seq/time's change in the same SSRC may mislead the media processing
For instance:
got SIP 183....
incoming RTPs :
SSRC=0xE2B0C9A5, Seq=231, Time=36960
SSRC=0xE2B0C9A5, Seq=232, Time=37120
SIP/SDP Status: 200 OK, with session description
 SSRC=0xE2B0C9A5, Seq=0, Time=0, Mark==== => *audio processing fails*
 SSRC=0xE2B0C9A5, Seq=1, Time=160
 SSRC=0xE2B0C9A5, Seq=2, Time=320
Remote endpoint keeps SSRC but reset Seq / Time
We would need to detect that change in the stream and to perform as the very
SSRC had changed
Paulo

On Thu, Jul 9, 2009 at 4:24 PM, Alexander Chemeris <
alexander.cheme...@sipez.com> wrote:

> Hi Andrew,
>
> We use sipXtapi a lot with our own Bridge (also sipXtapi-based),
> and it works perfectly with re-INVITE. So, no, this issue is not known.
> It would be helpful if you post here WireShark capture of the session
> with the note when audio is lost. Then we'll be able to see what's going.
>
> Also I'd recommend to add a simple audio logging to a file to
> MprDecode::doProcessFrame(). Just create a file, named after
> resource name (getName()) and write all audio data from 'outBufs[0]'
> right before "return TRUE". Then look into the file - what does it
> contains.
>
> On Thu, Jul 9, 2009 at 7:43 PM, Andrew Lavigne<alavi...@nortel.com> wrote:
> > Hi, All
> >
> > I'm getting the sense that this list is not all that active.  Still, I
> have
> > a troublesome issue upon which I really really hope someone can give me
> some
> > insight.
> >
> > Using a simple little client with Sipxtapi, I'm setting up a SIP call
> with
> > an audio RTP stream to an audio conference bridge on a media gateway.
> > Mostly, everything gets set up ok:  The initial SIP Invite goes as
> expected,
> > the initial RTP stream for setting up the conference works perfectly
> fine.
> > Then, the media gateway sends my client a sip re-INVITE, along with a new
> > SDP for the new audio stream that will be used for the actual conference.
> > I'm looking at the SIP and RTP data in wireshark and everything gets set
> up
> > perfectly…
> >
> > EXCEPT that most of the time, the RTP stream that comes back from the
> media
> > gateway into sipxtapi seems to be improperly connected up.  I see the
> proper
> > RTP packets coming into sipxtapi, but I hear nothing in my speakers.
> Once
> > in a blue moon, the issue does not manifest and I hear everything fine.
> > Then I'll run it again and - poof - no audio can be heard (even though in
> > wireshark I can clearly see it being sent from the media gateway into my
> > app).
> >
> > It seems like something is not quite right down in the medialib somewhere
> -
> > some sort of race condition or timing issue.  Sometimes it works,
> sometimes
> > it doesn't.    I'm poking around, placing debug lines and breakpoints,
> > trying to isolate the problem, but so far no luck.  My questions to any
> > experts out there are:
> >
> > 1) is there any sort of known issue like this in sipxmedialib?  If so, is
> > there some easy workaround?
> > 2) any sort of hint as to where I'd look in order to verify if the RTP
> > packets are getting mixed in properly into the Flow Graph?  That would be
> > helpful, too.
> >
> > 3) any other ideas that I have not yet thought of.
> >
> > Please, please… if anyone knowledgeable is out there reading this, could
> > they please give me a few minutes of their time.  I would be most
> > appreciative.  This bug (I'm going to call it a bug until proven
> otherwise)
> > is really wasting a lot of my time.
> >
> > Many thanks x 100,
> > …Andrew Lavigne
> >
> > _______________________________________________
> > sipxtapi-dev mailing list
> > sipxtapi-dev@list.sipfoundry.org
> > List Archive: http://list.sipfoundry.org/archive/sipxtapi-dev/
> >
>
>
>
> --
> Regards,
> Alexander Chemeris.
>
> SIPez LLC.
> SIP VoIP, IM and Presence Consulting
> http://www.SIPez.com
> tel: +1 (617) 273-4000
> _______________________________________________
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> sipxtapi-dev@list.sipfoundry.org
> List Archive: http://list.sipfoundry.org/archive/sipxtapi-dev/
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