[Linphone-users] issue with oRTP library using liblinphone iOS SDK

[Ryan Martin]

Hello,

I’m having some issues with an iOS application I am currently building using the LibLinphone iOS SDK. I am using the oRTP library within the SDK to receive an RTP stream from a Raspberry Pi and play this back on the iOS device. I am running on an iPad mini iOS 9.3.5. My code using the oRTP library is very similar to the rtprecv.c example included within the oRTP library. I’ll include this below:

    RtpSession *session;

    unsigned char buffer[160];

    int err;

    uint32_t ts=0;

    int stream_received=0;

    int have_more;

    bool_t adapt=TRUE;

    /* init the lib */

    ortp_init();

    ortp_scheduler_init();

    signal(SIGINT,stop_handler);

    session=rtp_session_new(RTP_SESSION_SENDRECV);

    rtp_session_set_scheduling_mode(session,FALSE);

    rtp_session_set_blocking_mode(session,FALSE);

    rtp_session_set_local_addr(session,"0.0.0.0",3550, 3551);

    rtp_session_enable_adaptive_jitter_compensation(session,adapt);

    rtp_session_set_jitter_compensation(session,40);

    rtp_session_set_payload_type(session,0);

    rtp_session_signal_connect(session,"ssrc_changed",(RtpCallback)ssrc_cb,0);

    rtp_session_signal_connect(session,"ssrc_changed",(RtpCallback)rtp_session_reset,0);

    while(cond)

    {

        have_more=1;

        while (have_more){

            err= rtp_session_recv_with_ts(session, buffer, 160, ts, &have_more);

            if (err>0) stream_received=1;

            /* this is to avoid to write to disk some silence before the first RTP packet is returned*/

            if ((stream_received) && (err>0)) {

                

//this is where I will write the buffer to audio output

            }

            

        }

        

        /* Follow the RFC, payload 0 has 8kHz reference rate */

        ts+= frame_size * 8000 / sample_rate;

    }

The first issue was found when running this code with 

session=rtp_session_new(RTP_SESSION_RECVONLY);

Xcode gives an lldb error with "Thread 1: EXC_BAD_ACCESS (code=1, address=0x8)” given on the line err= rtp_session_recv_with_ts(session, buffer, 160, ts, &have_more);

if I change the session to RTP_SESSION_SENDRECV I no longer get this error. Instead I now get Thread 1: signal SIGABRT and:

malloc: *** error for object 0x16b22e04: incorrect checksum for freed object - object was probably modified after being freed.

*** set a breakpoint in malloc_error_break to debug

Again, this happens when calling rtp_session_recv_with_ts(session, buffer, 160, ts, &have_more);

If anyone can point me in the right direction with this I’d greatly appreciate it.

Many thanks,

Ryan