(gdb) bt
#0  _g_log_abort (breakpoint=1) at ../../../../glib/gmessages.c:583
#1  0xb6ef39b9 in g_logv (log_domain=0xb700f7db "GLib-GObject", log_level=G_LOG_LEVEL_WARNING, 
    format=0xb7016c74 "can't peek value table for type '%s' which is not currently referenced", args=0xbfffc98c "ss\001\267")
    at ../../../../glib/gmessages.c:1391
#2  0xb6ef3ae5 in g_log (log_domain=0xb700f7db "GLib-GObject", log_level=G_LOG_LEVEL_WARNING, 
    format=0xb7016c74 "can't peek value table for type '%s' which is not currently referenced") at ../../../../glib/gmessages.c:1432
#3  0xb70088e7 in g_type_value_table_peek (type=<optimized out>) at ../../../../gobject/gtype.c:4267
#4  0xb3917a92 in gst_structure_set_valist_internal (structure=<optimized out>, fieldname=<optimized out>, varargs=0xbfffca98 "\324\312\377\277", 
    varargs@entry=0xbfffca78 "\030") at gststructure.c:607
#5  0xb3918cb1 in gst_structure_set (structure=0x8850c40, field=0xb3e966d9 "channels") at gststructure.c:638
#6  0xb3e9355b in gst_opus_enc_get_sink_template_caps () at gstopusenc.c:879
#7  gst_opus_enc_sink_getcaps (benc=0x8a43908, filter=0x0) at gstopusenc.c:908
#8  0xb35f5677 in gst_audio_encoder_sink_query_default (enc=0x8a43908, query=0x8a63890) at gstaudioencoder.c:1750
#9  0xb38f504a in gst_pad_query (pad=0x8a552e0, query=0x8a63890) at gstpad.c:4024
#10 0xb39306d3 in gst_pad_query_caps (pad=0x8a552e0, filter=0x0) at gstutils.c:3043
#11 0xb38eb6be in gst_pad_link_check_compatible_unlocked (flags=GST_PAD_LINK_CHECK_DEFAULT, sink=0x8a552e0, src=0x8a556d0) at gstpad.c:2260
#12 gst_pad_link_prepare (srcpad=srcpad@entry=0x8a556d0, sinkpad=sinkpad@entry=0x8a552e0, flags=flags@entry=GST_PAD_LINK_CHECK_DEFAULT) at gstpad.c:2397
#13 0xb38f860a in gst_pad_link_full (srcpad=0x8a556d0, sinkpad=0x8a552e0, flags=GST_PAD_LINK_CHECK_DEFAULT) at gstpad.c:2524
#14 0xb38f8e2e in gst_pad_link (srcpad=0x8a556d0, sinkpad=0x8a552e0) at gstpad.c:2645
#15 0xb3854877 in create_codec_bin_from_blueprint (codec=0x8a5d560, blueprint=0x8a30a40, name=0xb386b071 "gather_send_codecbin", 
    direction=FS_DIRECTION_SEND, error=0xbfffcdd8) at fs-rtp-discover-codecs.c:1735
#16 0xb3855884 in codec_blueprints_add_caps (media_type=FS_MEDIA_TYPE_AUDIO) at fs-rtp-discover-codecs.c:1841
#17 create_codec_lists (send_list=0x886f410, recv_list=0x8855a10, media_type=FS_MEDIA_TYPE_AUDIO) at fs-rtp-discover-codecs.c:351
#18 fs_rtp_blueprints_get (media_type=FS_MEDIA_TYPE_AUDIO, error=0x8a20280) at fs-rtp-discover-codecs.c:300
#19 0xb38470dc in fs_rtp_session_constructed (object=0x8a202c0) at fs-rtp-session.c:1218
#20 0xb6fe72c1 in g_object_new_internal (class=class@entry=0x8a70000, params=params@entry=0xbfffcffc, n_params=n_params@entry=3)
    at ../../../../gobject/gobject.c:1839
#21 0xb6fe9010 in g_object_new_valist (object_type=<optimized out>, first_property_name=<optimized out>, var_args=<optimized out>)
    at ../../../../gobject/gobject.c:2122
#22 0xb6fe90c9 in g_object_new (object_type=145144192, first_property_name=0xb3866ab4 "media-type") at ../../../../gobject/gobject.c:1642
#23 0xb384d22d in fs_rtp_session_new (media_type=FS_MEDIA_TYPE_AUDIO, conference=0x8a200a8, id=1, error=0xbfffd2ac) at fs-rtp-session.c:2412
#24 0xb3843d84 in fs_rtp_conference_new_session (conf=0x8a200a8, media_type=FS_MEDIA_TYPE_AUDIO, error=0xbfffd2ac) at fs-rtp-conference.c:523
#25 0xb382cb88 in fs_conference_new_session (conf=0x8a200a8, media_type=FS_MEDIA_TYPE_AUDIO, error=0xbfffd2ac) at fs-conference.c:141
#26 0xb7710e6a in ffi_call_SYSV () from /usr/lib/i386-linux-gnu/libffi.so.6
#27 0xb7710afc in ffi_call () from /usr/lib/i386-linux-gnu/libffi.so.6
#28 0xb709a5a0 in ?? () from /usr/lib/python3/dist-packages/gi/_gi.cpython-36m-i386-linux-gnu.so
#29 0xb709b144 in ?? () from /usr/lib/python3/dist-packages/gi/_gi.cpython-36m-i386-linux-gnu.so
#30 0xb709c34e in ?? () from /usr/lib/python3/dist-packages/gi/_gi.cpython-36m-i386-linux-gnu.so
#31 0xb709ae40 in ?? () from /usr/lib/python3/dist-packages/gi/_gi.cpython-36m-i386-linux-gnu.so
---Type <return> to continue, or q <return> to quit---
#32 0xb709ae82 in ?? () from /usr/lib/python3/dist-packages/gi/_gi.cpython-36m-i386-linux-gnu.so
#33 0xb708f5de in ?? () from /usr/lib/python3/dist-packages/gi/_gi.cpython-36m-i386-linux-gnu.so
#34 0x0809b83d in _PyObject_FastCallDict ()
#35 0x08178eb2 in ?? ()
#36 0x0817d471 in _PyEval_EvalFrameDefault ()
#37 0x08178d61 in ?? ()
#38 0x08179e2c in PyEval_EvalCode ()
#39 0x08176d25 in ?? ()
#40 0x080f9437 in PyCFunction_Call ()
#41 0x0818047c in _PyEval_EvalFrameDefault ()
#42 0x08178d61 in ?? ()
#43 0x08179002 in ?? ()
#44 0x0817d471 in _PyEval_EvalFrameDefault ()
#45 0x08178342 in ?? ()
#46 0x08179300 in ?? ()
#47 0x0817d471 in _PyEval_EvalFrameDefault ()
#48 0x08178342 in ?? ()
#49 0x08179300 in ?? ()
#50 0x0817d471 in _PyEval_EvalFrameDefault ()
#51 0x08178342 in ?? ()
#52 0x08179300 in ?? ()
#53 0x0817d471 in _PyEval_EvalFrameDefault ()
#54 0x08178342 in ?? ()
#55 0x08181bb7 in _PyFunction_FastCallDict ()
#56 0x0809b92c in _PyObject_FastCallDict ()
#57 0x0809cc84 in _PyObject_CallMethodIdObjArgs ()
#58 0x0819d282 in PyImport_ImportModuleLevelObject ()
#59 0x081755b2 in ?? ()
#60 0x080f9387 in PyCFunction_Call ()
#61 0x0818047c in _PyEval_EvalFrameDefault ()
#62 0x08178d61 in ?? ()
#63 0x08179002 in ?? ()
#64 0x0817d471 in _PyEval_EvalFrameDefault ()
#65 0x08178d61 in ?? ()
#66 0x08181ae8 in _PyFunction_FastCallDict ()
#67 0x0809b92c in _PyObject_FastCallDict ()
#68 0x0809cc84 in _PyObject_CallMethodIdObjArgs ()
#69 0x0819d356 in PyImport_ImportModuleLevelObject ()
#70 0x0818080e in _PyEval_EvalFrameDefault ()
---Type <return> to continue, or q <return> to quit---
#71 0x08178d61 in ?? ()
#72 0x08181ae8 in _PyFunction_FastCallDict ()
#73 0x0809bbbc in _PyObject_Call_Prepend ()
#74 0x080b32cf in ?? ()
#75 0x0809b670 in PyObject_Call ()
#76 0x0809b542 in PyObject_CallObject ()
#77 0xb709989e in ?? () from /usr/lib/python3/dist-packages/gi/_gi.cpython-36m-i386-linux-gnu.so
#78 0xb6fe1cc8 in g_closure_invoke (closure=0x873fcc0, return_value=0x0, n_param_values=1, param_values=0xbfffe840, invocation_hint=0xbfffe7e4)
    at ../../../../gobject/gclosure.c:804
#79 0xb6ff4f62 in signal_emit_unlocked_R (node=node@entry=0x8764060, detail=detail@entry=0, instance=instance@entry=0x8766878, emission_return=0x0, 
    instance_and_params=0xbfffe840) at ../../../../gobject/gsignal.c:3635
#80 0xb6ffd9a3 in g_signal_emit_valist (instance=<optimized out>, signal_id=<optimized out>, detail=<optimized out>, 
    var_args=0xbfffe9ac "W\214ն\034\020궠qn\b\377\377\377\377ߕնxhv\b") at ../../../../gobject/gsignal.c:3391
#81 0xb6ffe155 in g_signal_emit (instance=0x8766878, signal_id=162, detail=0) at ../../../../gobject/gsignal.c:3447
#82 0xb6d58d41 in g_application_register (application=0x8766878, cancellable=0x0, error=0xbfffe9fc) at ../../../../gio/gapplication.c:2137
#83 0xb6d595df in g_application_real_local_command_line (application=0x8766878, arguments=0xbfffeaa0, exit_status=0xbfffeaa4)
    at ../../../../gio/gapplication.c:1086
#84 0xb6d599af in g_application_run (application=0x8766878, argc=1, argv=0x8740730) at ../../../../gio/gapplication.c:2439
#85 0xb7710e6a in ffi_call_SYSV () from /usr/lib/i386-linux-gnu/libffi.so.6
#86 0xb7710afc in ffi_call () from /usr/lib/i386-linux-gnu/libffi.so.6
#87 0xb709a5a0 in ?? () from /usr/lib/python3/dist-packages/gi/_gi.cpython-36m-i386-linux-gnu.so
#88 0xb709b144 in ?? () from /usr/lib/python3/dist-packages/gi/_gi.cpython-36m-i386-linux-gnu.so
#89 0xb709c34e in ?? () from /usr/lib/python3/dist-packages/gi/_gi.cpython-36m-i386-linux-gnu.so
#90 0xb709ae40 in ?? () from /usr/lib/python3/dist-packages/gi/_gi.cpython-36m-i386-linux-gnu.so
#91 0xb709ae82 in ?? () from /usr/lib/python3/dist-packages/gi/_gi.cpython-36m-i386-linux-gnu.so
#92 0xb708f5de in ?? () from /usr/lib/python3/dist-packages/gi/_gi.cpython-36m-i386-linux-gnu.so
#93 0x0809b83d in _PyObject_FastCallDict ()
#94 0x08178eb2 in ?? ()
#95 0x0817d471 in _PyEval_EvalFrameDefault ()
#96 0x08178342 in ?? ()
#97 0x08179300 in ?? ()
#98 0x0817d471 in _PyEval_EvalFrameDefault ()
#99 0x08178d61 in ?? ()
#100 0x08179e2c in PyEval_EvalCode ()
#101 0x0806d65f in PyRun_FileExFlags ()
#102 0x0806d85a in PyRun_SimpleFileExFlags ()
#103 0x08083c3d in Py_Main ()
#104 0x08063adb in main ()