PJSIP with call audio capturing and streaming features

PJSIP library is modified to capture PCM frames from the call and stream PCM frames to the calls.

Core classes

Added two classes to media.hpp and media.cpp files:

• AudioMediaCapture: contains list to accumulate incoming frames, frames can be extracted with getFrames/getFramesAsString methods.
• AudioMediaStream: contains list for outgoing frames, frames can be populated with putFrame/putFrameAsString methods.

PJSUA2/SWIG

Need some changes to SWIG to access those features from the Python:

• Uncomment USE_THREADS = -threads -DSWIG_NO_EXPORT_ITERATOR_METHODS in swig/python/Makefile
• Add typemaps to swig/pjsua2.i to send/receive bytes from Python:

#ifdef SWIGPYTHON
  %typemap(in) (char *data, size_t datasize) {
    Py_ssize_t len;
    PyBytes_AsStringAndSize($input, &$1, &len);
    $2 = (size_t)len;
  }

  %typemap(in, numinputs=0) (char **data, size_t *datasize)(char *temp, size_t tempsize) {
    $1 = &temp;
    $2 = &tempsize;
  }

  %typemap(argout) (char **data, size_t *datasize) {
    if(*$1) {
      $result = PyBytes_FromStringAndSize(*$1, *$2);
      free(*$1);
    }
  }
#endif

Run Demo

1. docker-compose up
2. docker-compose exec pjsip python demo.py Demo script dumps frames to from the call to pjsip/pjsuademo/output.lpcm and streams hw.raw to the call. The recording of the call with both parties will be in asterisk_files/recordings directory.