It has has something to do with audio CODEC that is being used, m=audio 4000 RTP/AVP 8 98 97 104 3 0 99 9 96 Seems like pjsip is expecting a audio payload type '9' while it is receiving '8' during the RTP audio session. Try to set the 'rx' codec to be of payload type '8'. AV profile from the PJMedia codec framework PJMEDIA_RTP_PT_PCMA = 8, PJMEDIA_RTP_PT_G722 = 9 This mean the RTP audio transmitter is sending PCMA encoded audio while PJSip stack expects G722. So work around is the RTP audio transmitter can't be modified, set pjsip to expect codec 8. Workaround 1) Load PCMA codec via pjmedia_codec_mgr_find_codecs_by_id(codec_mgr, "pcma", &codec_info..) 2) Once step 1 is complete, codec_info will be will filled, and use this codec_info to set "pmedia_stream_info stream_info" ie stream_info.rx_pt = codec_info->pt // which our pcma codec, now pjsip is expecting pcma '8' than 9.
