title: FFMPEG record output audio for Mac
body: <p>I am trying to use ffmpeg recording screen as well as incoming audio on mac, but in the input device lists, there is no "speaker". Is there a way to get output audio?</p>
  
  <pre><code>$ ffmpeg -f avfoundation -list_devices true -i ""
  
  configuration: --prefix=/usr/local --enable-gpl --enable-nonfree --enable-libass --enable-libfdk-aac --enable-libfreetype --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxvid
  libavutil      55. 18.100 / 55. 18.100
  libavcodec     57. 24.105 / 57. 24.105
  libavformat    57. 26.100 / 57. 26.100
  libavdevice    57.  0.101 / 57.  0.101
  libavfilter     6. 34.100 /  6. 34.100
  libswscale      4.  0.100 /  4.  0.100
  libswresample   2.  0.101 /  2.  0.101
  libpostproc    54.  0.100 / 54.  0.100
  [AVFoundation input device @ 0x7fd5f9600360] AVFoundation video devices:
  [AVFoundation input device @ 0x7fd5f9600360] [0] FaceTime HD Camera
  [AVFoundation input device @ 0x7fd5f9600360] [1] Capture screen 0
  [AVFoundation input device @ 0x7fd5f9600360] [2] Capture screen 1
  [AVFoundation input device @ 0x7fd5f9600360] AVFoundation audio     devices:
  [AVFoundation input device @ 0x7fd5f9600360] [0] Soundflower (2ch)
  [AVFoundation input device @ 0x7fd5f9600360] [1] Built-in Microphone
  [AVFoundation input device @ 0x7fd5f9600360] [2] Soundflower (64ch)
  : Input/output error
  </code></pre>