pi@raspberrypi:~/ffmpeg-3.1.4-armel-32bit-static $ ffmpeg -devices
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
Devices:
 D. = Demuxing supported
 .E = Muxing supported
 --
 D  dv1394          DV1394 A/V grab
 DE fbdev           Linux framebuffer
 D  lavfi           Libavfilter virtual input device
 DE oss             OSS (Open Sound System) playback
  E v4l2            Video4Linux2 output device
 D  video4linux2,v4l2 Video4Linux2 device grab
 D  x11grab         X11 screen capture, using XCB