VideoCapture, drop frames

Im using videocapture whit ffmpeg backend. but in this way videocapture buffer frames and It causes the connection to be disconnected, i want to disable buffering frames, i want to frames that are not received, are droped.
I got help from videocapture.set to set CAP_PROP_BUFFERSIZE to zero, but it return false:
auto result =mOpencvCapture.set(CAP_PROP_BUFFERSIZE , 0);
and result is false.
can you help me please