--enable-sdl2 --enable-libdc1394 --enable-libiec61883 --arch=armhf --enable-chromaprint --enable-frei0r --enable-libopencv --enable-libx264 --enable-shared
  libavutil      55. 34.101 / 55. 34.101
  libavcodec     57. 64.101 / 57. 64.101
  libavformat    57. 56.101 / 57. 56.101
  libavdevice    57.  1.100 / 57.  1.100
  libavfilter     6. 65.100 /  6. 65.100
  libavresample   3.  1.  0 /  3.  1.  0
  libswscale      4.  2.100 /  4.  2.100
  libswresample   2.  3.100 /  2.  3.100
  libpostproc    54.  1.100 / 54.  1.100
Guessed Channel Layout for Input Stream #0.0 : stereo
Input #0, wav, from 'pipe:':
  Duration: N/A, bitrate: 1411 kb/s
    Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 44100 Hz, stereo, s16, 1411 kb/s
Output #0, rtp, to 'rtp://192.168.254.31:1234':
  Metadata:
    encoder         : Lavf57.56.101
    Stream #0:0: Audio: pcm_mulaw, 8000 Hz, mono, s16, 64 kb/s
    Metadata:
      encoder         : Lavc57.64.101 pcm_mulaw
SDP:
v=0
o=- 0 0 IN IP4 127.0.0.1
s=No Name
c=IN IP4 192.168.254.31
t=0 0
a=tool:libavformat 57.56.101
m=audio 1234 RTP/AVP 0
b=AS:64

Stream mapping:
  Stream #0:0 -> #0:0 (pcm_s16le (native) -> pcm_mulaw (native))
^CAborted by signal Interrupt... bitrate=  68.2kbits/s speed=1.38x
size=      39kB time=00:00:04.64 bitrate=  68.2kbits/s speed=1.34x
video:0kB audio:36kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 6.538130%
Exiting normally, received signal 2.