Video Format Conversion

Find video information

$ mplayer -vo null -ao null -identify -frames 0 filename.avi

$ ffmpeg -i filename.avi

$ tcprobe -i filename.avi

Convert file types

This is real simple and only needs one line. 

$ ffmpeg -i filename.ext -ab <audio bitrate> -b <video bitrate> -s <change to what you want ex.320x240> filename.ext

The two .ext extensions should obviously be different. Also, the new size -s could be whatever you want.

To keep the size the same but just convert. 

$ ffmpeg -i InputFile.avi -ab <audio bitrate> -b <video bitrate> -vcodec mpeg4 OutputFile.mp4