Unbounded per-SSRC RTCP statistics history causes linear memory growth

[szcom]

rtpengine version the issue has been seen with

12.5.1.41-1~bpo13+1

Used distribution and its version

trixie/sid

Linux kernel version used

6.6.48-flatcar

CPU architecture issue was seen on (see uname -m)

x86_64

Expected behaviour you didn't see

Memory used for RTCP/MOS statistics should remain bounded independently of call duration

Unexpected behaviour you saw

For every accepted RTCP Receiver Report, ssrc_receiver_report() allocates an ssrc_stats_block and appends it to other_e->stats_blocks.
The implementation:

• allocates and populates the statistics record
• only rejects samples received less than one second apart, then appends without a count or age limit
• clears the queue only when the SSRC entry is destroyed
  The same unbounded append is still present on master

--final-timeout=SECS provides an indirect bound by deleting the call after a fixed time regardless of continuing RTP/RTCP, which also releases the SSRC history.

Steps to reproduce the problem

No response

Additional program output to the terminal or logs illustrating the issue

Anything else?

No response