sammel@sammel-ub:~/Videos/youtube/felsen$ ffmpeg -i test_n1.mp4
ffmpeg version git-2012-06-01-7980a26 Copyright (c) 2000-2012 the FFmpeg developers
  built on Jun  1 2012 21:02:15 with gcc 4.4.3
  configuration: --enable-gpl --enable-libfaac --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-nonfree --enable-version3 --enable-x11grab
  libavutil      51. 56.100 / 51. 56.100
  libavcodec     54. 23.100 / 54. 23.100
  libavformat    54.  6.101 / 54.  6.101
  libavdevice    54.  0.100 / 54.  0.100
  libavfilter     2. 77.100 /  2. 77.100
  libswscale      2.  1.100 /  2.  1.100
  libswresample   0. 15.100 /  0. 15.100
  libpostproc    52.  0.100 / 52.  0.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'test_n1.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    creation_time   : 2012-04-27 04:45:32
    encoder         : Lavf54.6.101
    comment         : KODAK Zi8 Pocket Video Camera
  Duration: 00:00:20.72, start: 0.000000, bitrate: 894 kb/s
    Stream #0:0(eng): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 640x480 [SAR 4:3 DAR 16:9], 821 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 59.94 tbc
    Metadata:
      creation_time   : 2012-04-27 04:45:32
      handler_name    : VideoHandler
    Stream #0:1(eng): Audio: aac (mp4a / 0x6134706D), 48000 Hz, stereo, s16, 64 kb/s
    Metadata:
      creation_time   : 2012-04-27 04:45:32
      handler_name    : SoundHandler
At least one output file must be specified
sammel@sammel-ub:~/Videos/youtube/felsen$