FLV Extract console is a lightweight application for extracting audio and video content from the Flash Video type files. Accessible from the terminal, it just requires you to type in the executable file name followed by your FLV files. The utility works for multiple files and will output the mp3 and avi corresponding to your input file.

Parameters are in place to provide more versatility as shown bellow:

flvextc [-a] -v [-t] [-y] -i file1.flv [-i file2.flv] [file3.flv]

-a means to extract audio,
-v means to extract video,
-t extracts timeline codes (resulting in a text file with data),
-y will rewrite existsing output files,
-i should preceed each input ...Read more about FLV Extract console