here is pjsua crash back trace with debug symbols: Program terminated with signal 11, Segmentation fault. #0 Copy_16_To_16 (destinationBuffer=<optimized out>, destinationStride=<optimized out>, sourceBuffer=<optimized out>, sourceStride=<optimized out>, count=455, ditherGenerator=0x1e251d8) at src/../../../portaudio/src/common/pa_converters.c:1679 1679 *dest = *src; (gdb) where #0 Copy_16_To_16 (destinationBuffer=<optimized out>, destinationStride=<optimized out>, sourceBuffer=<optimized out>, sourceStride=<optimized out>, count=455, ditherGenerator=0x1e251d8) at src/../../../portaudio/src/common/pa_converters.c:1679 #1 0x00000000004f2867 in AdaptingProcess (bp=bp at entry=0x1e250e8, streamCallbackResult=streamCallbackResult at entry=0x7fcf585d3de8, processPartialUserBuffers=<optimized out>) at src/../../../portaudio/src/common/pa_process.c:1326 #2 0x00000000004f390f in PaUtil_EndBufferProcessing (bp=bp at entry=0x1e250e8, streamCallbackResult=streamCallbackResult at entry=0x7fcf585d3de8) at src/../../../portaudio/src/common/pa_process.c:1557 #3 0x00000000004eac5e in CallbackThreadFunc (userData=0x1e25080) at src/../../../portaudio/src/hostapi/alsa/pa_linux_alsa.c:3390 #4 0x00007fcf5dd8cb50 in start_thread () from /lib/x86_64-linux-gnu/libpthread.so.0 #5 0x00007fcf5d19fa7d in clone () from /lib/x86_64-linux-gnu/libc.so.6 #6 0x0000000000000000 in ?? () i have these portaudio related packages installed: ii libportaudio2:amd64 19+svn20111121-1 amd64 Portable audio I/O - shared library ii libportaudiocpp0:amd64 19+svn20111121-1 amd64 Portable audio I/O C++ bindings - shared library ii portaudio19-dev 19+svn20111121-1 amd64 Portable audio I/O - development files -- juha