With a script:

#!/bin/bash



# this script is to convert automatically a folder of video files to mp4

# You need to change SRC -- Sourse folder and DEST -- Destination folder

# The mp4 format is 480x270 



SRC=/home/$USER/Videos/

DEST=/home/$USER/Videos/mp4/

DEST_EXT=mp4

HANDBRAKE_CLI=HandBrakeCLI



for FILE in `ls $SRC`

do

        filename=$(basename $FILE)

        extension=${filename##*.}

        filename=${filename%.*}



        $HANDBRAKE_CLI -i $SRC/$FILE -o $DEST/$filename.$DEST_EXT -e x264 -q 22 -r 12 -B 64 -X 480 -O

done

Save, make it exectuable and this will convert files to .mp4 in directory /home/$USER/Videos to /home/$USER/Videos/mp4/. Change and create the dirs to what you need. And alter the line with $HANDBRAKE_CLI in to use your own parameters and setting.