Hi again, i'm trying resolve my problem and i found something in wsola algorithm. ...when i change implemnetation to PJMEDIA_WSOLA_IMP_NULL or PJMEDIA_WSOLA_IMP_WSOLA_LITE it works but when implementation is PJMEDIA_WSOLA_IMP_WSOLA problem ocurs when CPU is overloaded and i tap on microphone....channels in frame are reveresed... ...no hint? thanks