pi@raspberrypi:~/ffmpeg $ raspivid -o - -t 0 -vf -hf -fps 30 -b 6000000 | ./ffmpeg -re -ar 44100 -ac 2 -acodec pcm_s16le -f s16le -ac 2 -i /dev/zero -f h264 -i - -vcodec copy -acodec aac -ab 128k -g 50 -strict experimental -f flv rtmp://a.rtmp.youtube.com/live2/xbjs-a3gp-0yvk-ftdg
ffmpeg version 3.1.4-static http://johnvansickle.com/ffmpeg/  Copyright (c) 2000-2016 the FFmpeg developers
  built with gcc 5.4.1 (Debian 5.4.1-2) 20160904
  configuration: --enable-gpl --enable-version3 --enable-static --disable-debug --enable-libmp3lame --enable-libx264 --enable-libwebp --enable-libspeex --enable-libvorbis --enable-libvpx --enable-libfreetype --enable-fontconfig --enable-libxvid --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libtheora --enable-libvo-amrwbenc --enable-gray --enable-libopus --enable-libass --enable-gnutls --enable-libvidstab --enable-libsoxr --enable-frei0r --enable-libfribidi --disable-indev=sndio --disable-outdev=sndio --enable-librtmp --cc=gcc-5 --disable-ffplay
  libavutil      55. 28.100 / 55. 28.100
  libavcodec     57. 48.101 / 57. 48.101
  libavformat    57. 41.100 / 57. 41.100
  libavdevice    57.  0.101 / 57.  0.101
  libavfilter     6. 47.100 /  6. 47.100
  libswscale      4.  1.100 /  4.  1.100
  libswresample   2.  1.100 /  2.  1.100
  libpostproc    54.  0.100 / 54.  0.100
Guessed Channel Layout for Input Stream #0.0 : stereo
Input #0, s16le, from '/dev/zero':
  Duration: N/A, bitrate: 1411 kb/s
    Stream #0:0: Audio: pcm_s16le, 44100 Hz, 2 channels, s16, 1411 kb/s
Input #1, h264, from 'pipe:':
  Duration: N/A, bitrate: N/A
    Stream #1:0: Video: h264 (High), yuv420p, 1920x1080, 25 fps, 25 tbr, 1200k tbn, 50 tbc
Problem accessing the DNS. (addr: a.rtmp.youtube.com)
rtmp://a.rtmp.youtube.com/live2/xbjs-a3gp-0yvk-ftdg: Unknown error occurred