Some Video Conversions

ffmpeg is an excellent application on video conversion. It supports most of the file formats.

ffmpeg [[infile options][-i infile]]… {[outfile options] outfile}…

Convert from MPG to 3GP
ffmpeg -i video_clip.mpg -s qcif -vcodec h263 -acodec mp3 -ac 1 -ar 8000 -ab 32 -y clip.3gp

ffmpeg -i inputfile.mpg -s qcif -vcodec h263 -acodec aac -ac 1 -ar 8000 -r 25 -ab 32 -y outputfile.3gp

Convert from AVI to 3GP
ffmpeg -i video_clip.avi-s qcif -vcodec h263 -acodec mp3 -ac 1 -ar 8000 -r 25 -ab 32 -y clip.3gp

ffmpeg -i inputfile.avi -s qcif -vcodec h263 -acodec aac -ac 1 -ar 8000 -r 25 -ab 32 -y outputfile.3gp

Convert from 3GP to AVI
ffmpeg -i clip.3gp -f avi -vcodec xvid -acodec mp3 -ar 22050 file.avi

you need to install the codecs previously. All the xvid,mp3,avi,3gp codecs can be updated very easily in the debian based distros. All other disros also having the codecs in their own repositories.

There are other media conversion utilities also there as mencoder,transcode and there are a lot of GUI tools for this like drip, k9copy etc.

flv to mp3

ffmpeg -i jaiho.flv jaiho.mp3