I want to let webrtc communicate using freeswitch. But I cannot let you communicate well in firefox The version of freeswitch is 1.6 The version of firefox is 47 Probably I think that it is caused by codec. So I put setting of codec of vars <X-PRE-PROCESS cmd="set" data="global_codec_prefs=OPUS,G722,PCMU,PCMA,VP8,speex@8000h@20i,speex@16000h@20i,H264,H263-1998"/> <X-PRE-PROCESS cmd="set" data="outbound_codec_prefs=OPUS,G722,PCMU,PCMA,VP8,speex@8000h@20i,speex@16000h@20i,H264,H263-1998"/> please help me