Hi! We use pjsip 2.6 in c# wpf softphone. Our softphone calls pjmedia_aud_dev_refresh(); each 1 second for refresh list of record and player devices. Sometimes when incoming call apears this method conflicts with init_player_stream and we got next errors: Error retrieving default audio device parameters: Invalid audio device or Error opening sound device: Invalid value or argument We have tried to log pjisp and found next: ... 13:32:12.980 pjsua_call.c Answering call 1: code=200 ... 13:32:12.981 pjsua_aud.c .....Opening sound device (speaker + mic) PCM@16000/1/20ms 13:32:12.992 wmme_dev.c ...... WaveAPI Sound player "Динамики (Plantronics .Audio 628 USB)" initialized (format=PCM, clock_rate=16000, channel_count=1, samples_per_frame=320 (20ms)) 13:32:12.996 wmme_dev.c ...... WaveAPI Sound recorder "Микрофон (Plantronics .Audio 628 USB)" initialized (format=PCM, clock_rate=16000, channel_count=1, samples_per_frame=320 (20ms)) ... 13:42:04.756 pjsua_call.c Answering call 2: code=200 ... 13:42:04.757 pjsua_aud.c .....Opening sound device (speaker + mic) PCM@16000/1/20ms <---------------> 13:42:04.765 Calls pjmedia_aud_dev_refresh(); <---------------> 13:42:04.769 wmme_dev.c !...... WaveAPI Sound player "" initialized (format=PCM, clock_rate=16000, channel_count=1, samples_per_frame=320 (20ms)) 13:42:04.769 wmme_dev.c ......Stopped WMME playback stream ... As we understand method pjmedia_aud_dev_refresh makes aud_subsys.dev_cnt = 0; and after this another thread can't initialize sound.... Is it bug of pjsip? Perhaps wmme_dev methods should be thread safe? Or we need change logic for stop calling pjmedia_aud_dev_refresh() when incomming call appears? -- Best regards, Alex