[Live-devel] 2 SSRC on the same RTP stream

[Jean-Luc Bonnet]

Hi Ross,

                Thanks for your help.  I'm running under Windows. I have spied RTCP packets on the faulty stream and I have seen that Sender Report / Source Definition packets with a different CNAME  and SSRC  are sent periodically.  So I have check my code and found that audio and video are sent on the same multicast address that explains the issue.  I fix it and all works fine.

Best regards

Jean-Luc Bonnet

De : live-devel [mailto:live-devel-bounces at ns.live555.com] De la part de Ross Finlayson
Envoyé : 31août15 16:31
À : LIVE555 Streaming Media - development & use
Objet : Re: [Live-devel] 2 SSRC on the same RTP stream

                 Thanks for the quick reply. In fact I stream each video on a separate multicast addresses:
*         The first on 239.20.31.1:5004 which works fine. the SSRC is always the same on all RTP packets
*         The second on 239.20.31.2:5004

Are you running Linux?  Linux has a bug (though some people don't want to call it a 'bug') whereby if more than one process joins the same multicast group - but with a different port number - then all of these processes will receive copies of all multicast packets for all of these port numbers.  (Note that other Unix variants (including BSD) - as well as Windows - don't have this behavior; it's a problem just with Linux.)

Modern versions of Linux, however (starting, apparently, with Linux kernel version 2.6.31), have a "setsockopt()" option - called IP_MULTICAST_ALL - that allows you to disable this behavior.  The "LIVE555 Streaming Media" code (since version 2013.10.03) automatically calls "setsockopt()" to disable this behavior - if "IP_MULTICAST_ALL" is defined.

So, make sure that you're using a sufficiently modern version of Linux - one in which the IP_MULTICAST_ALL setsockopt() option is defined.  That should solve your problem.

Ross Finlayson
Live Networks, Inc.
http://www.live555.com/<https://urldefense.proofpoint.com/v2/url?u=http-3A__www.live555.com_&d=BQMF-g&c=0hKVUfnuoBozYN8UvxPA-w&r=3XFFEif9Py38PEs0FFH8jAYw83O__O1W1utDvwu8QzA&m=ZwxVZSelNnAK8pjIVHHjXKB2rEbpfJ3KhAYYLtdKLq0&s=2F_5Po2ju22TQ56MXSJT2HLVJVu3RJLIzf9qulLpZWA&e=>

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