E:\ffmpeg\bin>ffmpeg -i full.mp4 -ss 3 -t 2 -vcodec copy -acodec copy cut.mp4
ffmpeg version N-43060-ga85b4a5 Copyright (c) 2000-2012 the FFmpeg developers
  built on Jul 30 2012 13:18:07 with gcc 4.7.1 (GCC)
  configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-ru
ntime-cpudetect --enable-avisynth --enable-bzlib --enable-frei0r --enable-libass
 --enable-libcelt --enable-libopencore-amrnb --enable-libopencore-amrwb --enable
-libfreetype --enable-libgsm --enable-libmp3lame --enable-libnut --enable-libope
njpeg --enable-librtmp --enable-libschroedinger --enable-libspeex --enable-libth
eora --enable-libutvideo --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-
libvorbis --enable-libvpx --enable-libx264 --enable-libxavs --enable-libxvid --e
nable-zlib
  libavutil      51. 66.100 / 51. 66.100
  libavcodec     54. 45.100 / 54. 45.100
  libavformat    54. 22.100 / 54. 22.100
  libavdevice    54.  2.100 / 54.  2.100
  libavfilter     3.  5.101 /  3.  5.101
  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 'full.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf54.22.100
  Duration: 00:00:07.12, start: 0.000000, bitrate: 7995 kb/s
    Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1898x2140
, 7991 kb/s, 25 fps, 25 tbr, 25 tbn, 50 tbc
    Metadata:
      handler_name    : VideoHandler
File 'test.mp4' already exists. Overwrite ? [y/N] y
Output #0, mp4, to 'test.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf54.22.100
    Stream #0:0(und): Video: h264 ([33][0][0][0] / 0x0021), yuv420p, 1898x2140,
q=2-31, 7991 kb/s, 25 fps, 25 tbn, 25 tbc
    Metadata:
      handler_name    : VideoHandler
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
Press [q] to stop, [?] for help
frame=    0 fps=0.0 q=-1.0 Lsize=       0kB time=00:00:00.00 bitrate=   0.0kbits
/s
video:0kB audio:0kB subtitle:0 global headers:0kB muxing overhead inf%
Output file is empty, nothing was encoded (check -ss / -t / -frames parameters i
f used)