Hi all, In my application i need use only one channel in sound device (left or right) therefore i'm used media channel spitter/combiner and add it to conference bridge : Port #00[ 8KHz/60ms/2] CAPTURE transmitting to: Port #01[ 8KHz/60ms/2] splitter transmitting to: Port #02[ 8KHz/60ms/1] left channel transmitting to: - first port is sound device open with stereo mode. - second port is spiter/combiner created with pjmedia_splitcomb_create() and add to bridge with method pjmedia_conf_add_port() - third port is reverse channel for my left channel created with method pjmedia_splitcomb_create_rev_channel() and add to bridge with method pjmedia_conf_add_port() sound device (zero port) is connected to spliter(first port) and spliter is connected to sound device then all calls are connected through left channel to sound device and vice versa like that: Port #00[ 8KHz/60ms/2] CAPTURE transmitting to: #1 Port #01[ 8KHz/60ms/2] splitter transmitting to: #0 Port #02[ 8KHz/60ms/1] left channel transmitting to: #3 Port #03[ 8KHz/20ms/1] sip:1111 at 192.168.32.123 transmitting to: #2 All works fine. But sometime when CPU is overloaded sound from microphone stop working. Nothing is heard. When i tap on the microphone this problem occurs earlier..and when i tap again, microphone works again. When i connect port 0 to port 3 microphone still works.. Backwards from call to sound device all forks fine (path from port 3 to 2 and then 1 to 0) I'm discover very interesting thing: When is call callback put_frame() in spliter/combiner where frames from device are extract to individual mono channels frame which have 2 channels is first channel microphone and second channel is "null" channel with almost zero data... but when my problem occurs these channels are reversed...first channel have zero data and second channel have microphone data...I think the something in conference bridge reverse channels in frame. Have somebody advice what it can be? thanks