Open biv opened 9 months ago
The same for rtpengine-mr12.0.1.2
We don't currently interpret, change or manipulate a=ssrc
in any way. This would have to be added as a new feature.
Ok, thank you. Can you, please, suggest any way to find out new SSRC values at the SDP exchange stage?
rtpengine version the issue has been seen with
rtpengine-mr11.5.1.15
Used distribution and its version
Oracle 9
Linux kernel version used
5.15.62-13.el7.x86_64
CPU architecture issue was seen on (see
uname -m
)amd64
Expected behaviour you didn't see
My setup has such rtpengine.conf:
that is, transcoding is always enabled.
I've sent offer request to rtpengine:
In SDP we have id 3309166106 (0xc53dde1a).
Response from RTPEngine, that I've received:
Response has the same SSRC 3309166106 (0xc53dde1a).
The same is for answer. I've sent:
And response, I've received:
That is, SSRC in request and response are the same: 1754653800 (0x6895E468).
But, because of transcoding, SSRC of input RTP packet and output RTP packet are different, this can be seen in rtpengine logs, for instance, in my case:
That is, we have 4 SSRCs (and this is true, I've checked it with tcpdump and wireshark):
So, it seems, that in response to offer request, we expect to see
a=ssrc:8417302
, but we seea=ssrc:3309166106
. The same for response to answer request, we expect to seea=ssrc:3741246366
, but we seea=ssrc:1754653800
.That is RTPEngine doesn't change SSRC attribute in response and use the same, that it received in request, but input and output RTP packets have different SSRCs. Expected bevaviour in this case, that RTPEngine changes SSRC attribute in SDP in response according to changes in RTP packets.
Unexpected behaviour you saw
Response from RTPEngine has SDP with the same SSRC attribute as in request, but transcoding changes SSRC in RTP packets.
Steps to reproduce the problem
No response
Additional program output to the terminal or logs illustrating the issue
No response
Anything else?
No response