ffmpeg -i test.3gp
ffmpeg version 0.8.9-4:0.8.9-0ubuntu0.12.04.1, Copyright (c) 2000-2013 the Libav developers
  built on Nov  9 2013 19:12:07 with gcc 4.6.3
*** THIS PROGRAM IS DEPRECATED ***
This program is only provided for compatibility and will be removed in a future release. Please use avconv instead.
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'test.3gp':
  Metadata:
    major_brand     : 3gp6
    minor_version   : 256
    compatible_brands: isomiso2avc13gp6
  Duration: 00:04:19.20, start: 0.000000, bitrate: 426 kb/s
    Stream #0.0(und): Video: h264 (Main), yuv420p, 352x288 [PAR 1:1 DAR 11:9], 425 kb/s, 15 fps, 15 tbr, 15 tbn, 30 tbc
At least one output file must be specified
sky@sky-desktop ~ $