ffmpeg -i _cat.mp4 -acodec copy -vcodec copy _final.mp4
FFmpeg version SVN-r9116, Copyright (c) 2000-2007 Fabrice Bellard, et al.
  configuration: --enable-gpl --enable-pp --enable-libmp3lame --enable-xvid --enable-liba52 --enable-libogg --enable-libvorbis --enable-x264 --enable-libfaad --enable-libfaac --enable-libgsm --extra-cflags=-DHAVE_LRINTF
  libavutil version: 49.4.0
  libavcodec version: 51.40.4
  libavformat version: 51.12.1
  built on May 24 2007 15:33:12, gcc: 4.1.2 20061115 (prerelease) (SUSE Linux)
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '_cat.mp4':
  Duration: 00:03:02.9, start: 0.000000, bitrate: 807 kb/s
  Stream #0.0(und): Video: h264, yuv420p, 320x240, 25.00 fps(r)
  Stream #0.1(und): Audio: aac, 44100 Hz, stereo
File '_final.mp4' already exists. Overwrite ? [y/N] y
Output #0, mp4, to '_final.mp4':
  Stream #0.0: Video: h264, yuv420p, 320x240, q=2-31, 25.00 fps(c)
  Stream #0.1: Audio: aac, 44100 Hz, stereo
Stream mapping:
  Stream #0.0 -> #0.0
  Stream #0.1 -> #0.1
Press [q] to stop encoding
frame= 4574 fps=  0 q=0.0 Lsize=   16134kB time=182.8 bitrate= 722.9kbits/s    
video:13350kB audio:2685kB global headers:0kB muxing overhead 0.613571%