[Linphone-users] Ortp: Crash on RECVONLY session during RTCP package construction

[Hans-Joerg Schurr]

Hello everyone,

I'm a user of the excellent trx tool[1], a wrapper arround ortp and
opus to stream audio. When compiling with recent versions of ortp
(release 1.0.2 in this case) the receiving part (rx) crashes after a
few seconds. 

rx sets up a session with the option 'RTP_SESSION_RECVONLY' and, as the
stacktrace bellow indicates, the crash happens during the construction
of the rtcp package. From what I could gather from stepping throught
the code, the problem seems to be that 'session->minimal_sdes' is not
set. In 'rtp_session_init' this structure is set up by calling
'rtp_session_set_source_description' with some default values
(src/rtpsession.c:248). This, however, is only done for 'SENDONLY' and
'SENDRECV' sessions. Indeed, when switching to 'SENDRECV' the error
disappears.

It looks like I'm not the first person with this problem [2],[3].

Best,
 Hans-Jörg

[1] http://www.pogo.org.uk/~mark/trx/
[2] 
https://stackoverflow.com/questions/50076996/errors-using-ortp-library-within-liblinphone-ios-sdk
[3] 
https://stackoverflow.com/questions/43591690/receiving-rtcp-issues-within-ortp-library

#0  0x000000000040e523 in concatb (address@hidden, newm=0x0) at
[..]/ortp-1.0.2/src/str_utils.c:337
#1  0x00000000004127a8 in append_sdes (full=1 '\001', m=0x68b9f0,
session=0x63cbe0) at [..]/ortp-1.0.2/src/rtcp.c:397
#2  rtp_session_create_and_send_rtcp_packet (address@hidden
cbe0, address@hidden '\001') at [..]/ortp-1.0.2/src/rtcp.c:460
#3  0x0000000000412a46 in
rtp_session_send_regular_rtcp_packet_and_reschedule (session=0x63cbe0,
tc=2082455) at [..]/ortp-1.0.2/src/rtcp.c:569
#4  0x000000000040909f in rtp_session_recvm_with_ts (
address@hidden, address@hidden) at
[..]/ortp-1.0.2/src/rtpsession.c:1304
#5  0x0000000000409295 in rtp_session_recv_with_ts (session=0x63cbe0,
buffer=<optimized out>, len=32768, ts=29760, have_more=0x7fffffffb408)
at [..]/ortp-1.0.2/src/rtpsession.c:1381
#6  0x0000000000403a5c in run_rx (session=0x63cbe0, decoder=0x635e70,
snd=0x6890f0, channels=2, rate=48000) at rx.c:117
#7  0x0000000000403fa0 in main (argc=5, argv=0x7fffffffb578) at
rx.c:258