[Live-devel] StatsIterator sometimes doesn't return any stats

[Ross Finlayson]

> On Feb 15, 2024, at 10:58 PM, Andy Hawkins <Andy.Hawkins at uniguest.com> wrote:
> 
> I doubt that's happening in this instance. This is a live feed from an Axis RTSP camera. It seems unlikely that one of the sources (audio or video) would stop while the other continued?

Looking at our code some more:
The RTCP code periodically cleans out records of SSRCs (RTP sources) that it hasn’t received RTCP “SR” (Sender Report) packets from in some time (specifically, for receivers, if we send out 5 RTCP “RR” (Reception Report)s without hearing from a particular source, then we assume that this source has stopped sending, and we remove our record of it).  See “liveMedia/RTCP.cpp”, lines 930-935 and 78-108.

So, while your sources (audio and video) might be continuing to send media, one of them is apparently not sending RTCP "SR" packets for an unusual length of time - or perhaps has stopped sending RTCP "SR” packets altogether.  In either case, this seems to be a bug in the Axis camera.

However, there’s no good reason not to keep around “RTPReceptionStats” even if this happens, so I’ve just installed a new version (2024.02.15) of the code that keeps the “RTPReceptionStats” record for a source, even if it stops sending RTCP “SR” packets.


Ross Finlayson
Live Networks, Inc.
http://www.live555.com/