我已经从这个链接编译了代码，我也能够在 sip 服务器上成功注册一个帐户。但是当我拨打 sip 电话时，它会在pjsua_call_media_init. 我需要帮助来理解下面提到的错误原因。
--end msg--
14:51:34.422 pjsua_acc.c ....SIP outbound status for acc 0 is not active
14:51:34.422 pjsua_acc.c ....sip:ssssingh@sip.antisip.com: registration success, status=200 (OK), will re-register in 300 seconds
14:51:34.422 pjsua_acc.c ....Keep-alive timer started for acc 0, destination:91.121.81.212:5060, interval:15s
2013-07-04 14:51:34.423 GossipExample[1049:4603] Gossip: dispatchRegistrationState(0)
2013-07-04 14:51:46.651 GossipExample[1049:907] Gossip: ringbackWithSoundNamed: /var/mobile/Applications/1B440F28-7F74-46D5-A120-9C0B3C35AD65/GossipExample.app/ringtone.wav
14:51:46.653 pjsua_aud.c !Creating playlist with 1 file(s)..
14:51:46.655 wav_playlist.c .WAV playlist 'WAV playlist' created: samp.rate=44100, ch=2, bufsize=4KB
14:51:46.657 pjsua_aud.c .Playlist created, id=0, slot=1
14:51:47.708 pjsua_call.c Making call with acc #0 to sip:chakrit2@getonsip.com
14:51:47.710 pjsua_aud.c .Set sound device: capture=-1, playback=-2
14:51:47.711 pjsua_aud.c ..Opening sound device PCM@16000/1/20ms
14:51:47.712 coreaudio_dev. ...Using RemoteIO audio unit
14:51:48.013 coreaudio_dev. ...core audio stream started
14:51:48.021 pjsua_media.c .Call 0: initializing media..
在上述事件序列之后出现陷阱错误，图像如下
