$ ffmpeg -f mp3 -i music/ElectronicAir_2018-10-13.mp3 -f rtp rtp://10.0.0.255
ffmpeg version 3.3.6 Copyright (c) 2000-2017 the FFmpeg developers
  built with gcc 7.3.0 (Gentoo Hardened 7.3.0-r3 p1.4)
  configuration: --prefix=/usr --libdir=/usr/lib64 --shlibdir=/usr/lib64 --docdir=/usr/share/doc/ffmpeg-3.3.6/html --mandir=/usr/share/man --enable-shared --cc=x86_64-pc-linux-gnu-gcc --cxx=x86_64-pc-linux-gnu-g++ --ar=x86_64-pc-linux-gnu-ar --optflags='-O2 -pipe -march=amdfam10' --disable-static --enable-avfilter --enable-avresample --disable-stripping --enable-nonfree --enable-version3 --disable-indev=oss --disable-outdev=oss --disable-outdev=sdl --enable-bzlib --disable-runtime-cpudetect --disable-debug --disable-gcrypt --disable-gnutls --disable-gmp --enable-gpl --enable-hardcoded-tables --enable-iconv --enable-lzma --enable-network --enable-openssl --enable-postproc --enable-libsmbclient --disable-ffplay --disable-sdl2 --disable-vaapi --disable-vdpau --enable-xlib --enable-libxcb --enable-libxcb-shm --enable-libxcb-xfixes --enable-zlib --disable-libcdio --disable-libiec61883 --disable-libdc1394 --disable-libcaca --disable-openal --enable-opengl --disable-libv4l2 --enable-libpulse --disable-libopencore-amrwb --disable-libopencore-amrnb --disable-libfdk-aac --disable-libopenjpeg --disable-libbluray --disable-libcelt --disable-libgme --disable-libgsm --disable-mmal --disable-libmodplug --disable-libopus --disable-libilbc --disable-librtmp --disable-libssh --disable-libschroedinger --disable-libspeex --enable-libvorbis --disable-libvpx --disable-libzvbi --disable-libbs2b --disable-chromaprint --disable-libflite --disable-frei0r --disable-libfribidi --disable-fontconfig --disable-ladspa --disable-libass --enable-libfreetype --disable-librubberband --disable-netcdf --disable-libzmq --disable-libzimg --disable-libsoxr --enable-pthreads --disable-libvo-amrwbenc --enable-libmp3lame --disable-libkvazaar --disable-nvenc --disable-libopenh264 --disable-libsnappy --enable-libtheora --disable-libtwolame --disable-libwavpack --disable-libwebp --enable-libx264 --disable-libx265 --enable-libxvid --disable-aesni --disable-avx --disable-avx2 --disable-fma3 --disable-fma4 --disable-ssse3 --disable-sse4 --disable-sse42 --disable-xop --enable-pic --cpu=amdfam10 --disable-doc --disable-htmlpages --enable-manpages
  libavutil      55. 58.100 / 55. 58.100
  libavcodec     57. 89.100 / 57. 89.100
  libavformat    57. 71.100 / 57. 71.100
  libavdevice    57.  6.100 / 57.  6.100
  libavfilter     6. 82.100 /  6. 82.100
  libavresample   3.  5.  0 /  3.  5.  0
  libswscale      4.  6.100 /  4.  6.100
  libswresample   2.  7.100 /  2.  7.100
  libpostproc    54.  5.100 / 54.  5.100
[mp3 @ 0x55ffa7945990] Skipping 191 bytes of junk at 0.
[mp3 @ 0x55ffa7945990] Estimating duration from bitrate, this may be inaccurate
Input #0, mp3, from 'music/ElectronicAir_2018-10-13.mp3':
  Duration: 02:05:01.59, start: 0.000000, bitrate: 160 kb/s
    Stream #0:0: Audio: mp3, 44100 Hz, stereo, s16p, 160 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (mp3 (native) -> pcm_mulaw (native))
Press [q] to stop, [?] for help
Output #0, rtp, to 'rtp://10.0.0.255':
  Metadata:
    encoder         : Lavf57.71.100
    Stream #0:0: Audio: pcm_mulaw, 44100 Hz, stereo, s16, 705 kb/s
    Metadata:
      encoder         : Lavc57.89.100 pcm_mulaw
SDP:
v=0
o=- 0 0 IN IP4 127.0.0.1
s=No Name
c=IN IP4 10.0.0.255
t=0 0
a=tool:libavformat 57.71.100
m=audio 0 RTP/AVP 97
b=AS:705
a=rtpmap:97 PCMU/44100/2
a=control:streamid=0

av_interleaved_write_frame(): Invalid argument
Error writing trailer of rtp://10.0.0.255: Invalid argument
size=       2kB time=00:00:00.02 bitrate= 721.5kbits/s speed=19.4x    
video:0kB audio:2kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 2.256944%
Conversion failed!