ffmpeg -f video4linux2 -list_formats all -i /dev/video0 支持格式如下:

ffmpeg version N-72043-g17b2630 Copyright (c) 2000-2015 the FFmpeg developers
  built with gcc 4.8 (Raspbian 4.8.4-1)
  configuration: --enable-gpl --enable-libx264 --enable-nonfree --arch=armel --target-os=linux
  libavutil      54. 23.101 / 54. 23.101
  libavcodec     56. 38.100 / 56. 38.100
  libavformat    56. 32.100 / 56. 32.100
  libavdevice    56.  4.100 / 56.  4.100
  libavfilter     5. 16.101 /  5. 16.101
  libswscale      3.  1.101 /  3.  1.101
  libswresample   1.  1.100 /  1.  1.100
  libpostproc    53.  3.100 / 53.  3.100
[video4linux2,v4l2 @ 0x1738ff0] Raw       :   yuyv422 :     YUV 4:2:2 (YUYV) : 640x480 160x120 176x144 320x176 320x240 352x288 432x240 544x288 640x360 752x416 800x448 800x600 864x480 960x544 960x720 1024x576 1184x656 1280x720 1280x960
[video4linux2,v4l2 @ 0x1738ff0] Compressed:     mjpeg :                MJPEG : 640x480 160x120 176x144 320x176 320x240 352x288 432x240 544x288 640x360 752x416 800x448 800x600 864x480 960x544 960x720 1024x576 1184x656 1280x720 1280x960