ffmpeg -f v4l2 -s 640x360 -r 30 -i /dev/video0 -f flv rtmp://ip/live/livestream
ffmpeg version N-42939-g236ecc3 Copyright (c) 2000-2012 the FFmpeg developers
  built on Jul 27 2012 00:02:56 with gcc 4.6 (Ubuntu/Linaro 4.6.3-1ubuntu5)
  configuration: --enable-librtmp
  libavutil      51. 65.100 / 51. 65.100
  libavcodec     54. 45.100 / 54. 45.100
  libavformat    54. 21.100 / 54. 21.100
  libavdevice    54.  2.100 / 54.  2.100
  libavfilter     3.  3.100 /  3.  3.100
  libswscale      2.  1.100 /  2.  1.100
  libswresample   0. 15.100 /  0. 15.100
[video4linux2,v4l2 @ 0xa933680] The V4L2 driver changed the video from 640x360 to 320x240
[video4linux2,v4l2 @ 0xa933680] Estimating duration from bitrate, this may be inaccurate
Input #0, video4linux2,v4l2, from '/dev/video0':
  Duration: N/A, start: 12709.752862, bitrate: N/A
    Stream #0:0: Video: mjpeg, yuvj422p, 320x240, -5 kb/s, 30 tbr, 1000k tbn, 30 tbc
Output #0, flv, to 'rtmp://128.104.153.123:1935/live/livestream':
  Metadata:
    encoder         : Lavf54.21.100
Stream #0:0: Video: flv1 ([2][0][0][0] / 0x0002), yuv420p, 320x240, q=2-31, 200 kb/s, 1k tbn, 30 tbc
Stream mapping:
  Stream #0:0 -> #0:0 (mjpeg -> flv)
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frame= 3863 fps=12 q=12.5 size= 3470kB