Note that ffmpeg is depricated in Ubuntu and other distros:
avconv
is the one you want to use which is in in the libav-tools
package and can be installed with the following line:
sudo apt-get install libav-tools
So here are some ways you can do it:
FFMPEG (Deprecated in 12.04+)
ffmpeg -i input.avi -vcodec copy -acodec copy output1.avi
ffmpeg -i input.avi -vcodec copy -acodec copy output1.mp4
ffmpeg -i input.avi -vcodec copy -acodec copy output1.mkv
ffmpeg -i input.avi -vcodec copy -acodec copy output1.mpg
AVCONV
avconv -i input.avi -vcodec copy -acodec copy output1.avi
avconv -i input.avi -vcodec copy -acodec copy output1.mp4
avconv -i input.avi -vcodec copy -acodec copy output1.mkv
avconv -i input.avi -vcodec copy -acodec copy output1.mpg
Am assuming that when you say "convert to anything else" and then you add that the output should not be compressed (And then I just so happen to see the bitrate) am thinking the original file, the input is RAW inside an avi container. If this is the case, the above options will work. They will just copy the content to another container, maintaining the 25fps, bitrate and overall quality.
If you do not want to copy the content, simply remove the part that says "-vcodec copy -acodec copy" and avconv/ffmpeg will take care of it.
NOTE - As mentioned by LordNeckBeard, the MP4 example will not work on Raw.